• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
56699897 wcdma-ran-planning-and-optimization-features-and-algorithms
 

56699897 wcdma-ran-planning-and-optimization-features-and-algorithms

on

  • 7,887 views

 

Statistics

Views

Total Views
7,887
Views on SlideShare
7,887
Embed Views
0

Actions

Likes
3
Downloads
1,084
Comments
1

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel

11 of 1 previous next

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
  • thanks for sharing. I am really appreciate it.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    56699897 wcdma-ran-planning-and-optimization-features-and-algorithms 56699897 wcdma-ran-planning-and-optimization-features-and-algorithms Document Transcript

    • www.huawei.comCopyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.WCDMA UE Behaviorsin Idle Mode1
    • Page1Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.ForewordUE behaviors in idle mode include :PLMN selectionSystem information receptionCell selection and reselectionLocation registrationPaging procedureAccess procedurePLMN selectionUsed to ensure that the PLMN selected by the UE properly provides services.Cell selection and reselectionUsed to ensure that the UE finds a suitable cell to camp on.Location registrationUsed for the network to trace the current status of the UE and to ensure that the UE is campedon the network when the UE does not perform any operation for a long period.System information receptionThe network broadcasts the network information to a UE which camps on the cell to control thebehaviors of the UE.PagingUsed for the network to send paging messages to a UE which is in idle mode, CELL_PCHstate, or URA_PCH state.AccessFrom the view of access stratum, access is the procedure UE shift from idle mode toconnected mode.2
    • Page2Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure3
    • Page3Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure4
    • Page4Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell SearchUE does not have UTRAN carrier informationIn order to find a suitable cell to stay, UE will scan all thefrequencies in UTRAN. In each carrier, UE just need to find acell with best signalUE has UTRAN carrier informationUE will try whether the original cell is suitable to stay. If not, UEstill need to scan all the frequencies about UTRAN in order tofind a suitable cell in PLMNTypical scenario of first occasion is the first time a new UE is put into use.The second occasion is very common.5
    • Page5Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell SearchSlot synchronizationFrame synchronization andcode-group identificationPrimary Scrambling codeidentificationStep 1: Slot synchronizationDuring the first step of the cell search procedure the UE uses the primary synchronisation code(PSC) to acquire slot synchronisation to a cell.Step 2: Frame synchronization and code-group identificationDuring the second step of the cell search procedure, the UE uses the secondarysynchronisation code (SSC) to find frame synchronisation and identify the code group of thecell found in the first step.Step 3: Primary Scrambling code identification:During the last step of the cell search procedure, the UE determines the exact primaryscrambling code used by the found cell. The primary scrambling code is typically identifiedthrough symbol-by-symbol correlation over the CPICH with all codes within the code groupidentified in the second step.If the UE has received information about which scrambling codes to search for, steps 2 and 3above can be simplified.6
    • Page6Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.PLMN SelectionUE shall maintain a list of allowed PLMN types. In thePLMN list, the UE arranges available PLMNs by priorities.When selecting a PLMN, it searches the PLMNs from thehigh priority to the low.The UE selects a PLMN from HPLMNs or VPLMNs.UE can get the system information from PCCPCH, and the PLMN information is transmitted inMIB of PCCPCHAfter getting the MIB, UE can judge weather the current PLMN is the right one. If so, UE willget the SIB scheduling information from the MIB; if not, UE will search another carrier, do thisprocedure again7
    • Page7Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.PLMN Selection (Cont.)PLMN Selection in HPLMNsAutomatic PLMN Selection ModeThe UE selects an available and suitable PLMN from the wholeband according to the priority orderManual PLMN Selection ModeThe order of manual selection is the same as that of automaticselection.The priority order for automatic PLMN selection modeThe PLMN selected by theUE before automatic PLMNselectionPreviously selected PLMN6The PLMNs are arranged indescending order of signalquality.Other PLMN/access technology combinationsexcluding the previously selected PLMN5The PLMNs are arranged inrandom orderOther PLMN/access technology combinations withthe high quality of received signals excluding thepreviously selected PLMN4The PLMNs are arranged inpriority orderPLMNs contained in the "Operator ControlledPLMN Selector with Access Technology" data fieldin the SIM excluding the previously selected PLMN3The PLMNs are arranged inpriority orderPLMNs contained in the "User Controlled PLMNSelector with Access Technology" data field in theSIM excluding the previously selected PLMN2Home PLMNsHPLMNs1RemarkPLMN typeOrder8
    • Page8Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.PLMN Selection (Cont.)PLMN Selection in VPLMNsIf a UE is in a VPLMN, it scans the “user controlled PLMNselector” field or the “operator controlled PLMN selector” fieldin the PLMN list to find the HPLMN or the PLMN with higherpriority according to the requirement of the automatic PLMNselection mode.A value of T minutes may be stored in the SIM. T is either in the range from 6 minutes to 8hours in 6-minute steps or it indicates that no periodic attempts shall be made. If no value isstored in the SIM, a default value of 60 minutes is used.After the UE is switched on, a period of at least 2 minutes and at most T minutes shall elapsebefore the first attempt is made.The UE shall make an attempt if the UE is on the VPLMN at time T after the last attempt.9
    • Page9Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure10
    • Page10Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Structure of System InformationSystem information is organized as a tree, including:MIB (Master Information Block )SB (Scheduling Block )SIB (System Information Block )System information is used for the network to broadcast network information to UEs campingon a cell so as to control the behavior of UEs.MIBWhen selecting a new cell, the UE reads the MIB. The UE may locate the MIB bypredefined scheduling information. The IEs in the MIB includes MIB value tag, PLMNtype, PLMN identity, reference and scheduling information for a number of SIBs in acell or one or two SBs in a cell.SBScheduling Block (SB) gives reference and scheduling information to other SIBs. Thescheduling information of a SIB may be included in only one of MIB and SB.SIBSystem Information Block (SIB) contains actual system information. It consists ofsystem information elements (IEs) with the same purpose.Scheduling information for a system information block may only be included in either themaster information block or one of the scheduling blocks.11
    • Page11Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.System InformationSIB1: Contains the system information for NAS and thetimer/counter for UESIB2: Contains the URA informationSIB3: Contains the parameters for cell selection and cell re-selectionSIB5: Contains parameters for the common physical channels ofthe cellSIB7: Contains the uplink interference level and the refreshingtimer for SIB7SIB11: Contains measurement controlling informationSIB4: Contains parameters for cell selection and cell re-selection while UE is in connectedmodeSIB6: Contains parameters for the common physical channels of the cell while UE is inconnected modeSIB8: Contains the CPCH static informationSIB9: Contains the CPCH dynamic informationSIB10: Contains information to be used by UEs having their DCH controlled by a DRACprocedure. Used in FDD mode only. To be used in CELL_DCH state only. Changes so often,its decoding is controlled by a timerSIB12: Contains measurement controlling information in connecting modeSIB13: Contains ANSI-41 system informationSIB14: Contains the information in TDD modeSIB15: Contains the position service informationSIB16: Contains the needed pre-configuration information for handover from other RAT toUTRANSIB17: Contains the configuration information for TDDSIB18: Contains the PLMN identities of the neighboring cellsTo be used in shared networks to help with the cell reselection process12
    • Page12Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Reception of System InformationThe UE shall read system information broadcast on a BCHtransport channel when the UE is in idle mode or inconnected mode, that is, in CELL_FACH, CELL_PCH, orURA_PCH state.The UE may use the scheduling information in MIB and SB to locate each SIB to be acquired.If the UE receives a SIB in a position according to the scheduling information and consider thecontent valid, it will read and store it.13
    • Page13Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure14
    • Page14Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell SelectionWhen the PLMN is selected and the UE is in idle mode, theUE starts to select a cell to camp on and to obtain services.There are four states involved in cell selection:Camped normallyAny cell selectionCamped on any cellConnected modeCamped normally: The cell that UE camps on is called the suitable cell. In this state, the UEobtains normal service.Any cell selection: In this state, the UE shall attempt to find an acceptable cell of an any PLMNto camp on, trying all RATs that are supported by the UE and searching first for a high qualitycellCamped on any cell: The cell that UE camps on is called the acceptable cell. In this state theUE obtains limited service. The UE shall regularly attempt to find a suitable cell of the selectedPLMN, trying all RATs that are supported by the UE.Connected mode: When returning to idle mode, the UE shall use the procedure Cell selectionwhen leaving connected mode in order to find a suitable cell to camp on and enter stateCamped normally. If no suitable cell is found in cell reselection evaluation process, the UEenters the state Any cell selection.15
    • Page15Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell Selection (Cont.)Two types of cell selection:Initial cell selectionIf no cell information is stored for the PLMN, the UE starts thisprocedure.Stored information cell selectionIf cell information is stored for the PLMN, the UE starts thisprocedure.Initial cell selection: If no cell information is stored for the PLMN, the UE starts the initial cellselection. For this procedure, the UE need not know in advance which Radio Frequency (RF)channels are UTRA bearers. The UE scans all RF channels in the UTRA band according to itscapabilities to find a suitable cell of the selected PLMN. On each carrier, the UE need onlysearch for the strongest cell. Once a suitable cell is found, this cell shall be selected.Stored information cell selection: For this procedure, the UE need know the central frequencyinformation and other optional cell parameters that are obtained from the measurement controlinformation received before, such as scrambling codes. After this procedure is started, the UEselects a suitable cell if it finds one. Otherwise, the "Initial cell selection" procedure is triggered.16
    • Page16Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell Selection Criteriaminqualqualmeasqual QQS −=oncompensatirxlevrxlevmeasrxlev PQQS −−= minCriterion S is used by the UE to judge whether the cell issuitable to camped on.Criterion S : Srxlev > 0 & Squal > 0, where:If the pilot strength and quality of one cell meet S criteria, UE will stay in this cell and get othersystem information. Then, UE will initiate a location update registration process.If the cell doesn’t satisfy S criteria, UE will get adjacent cells information from SIB11. Then, UEwill judge weather these cells satisfy S criteria. If the adjacent cell is suitable, UE will stay inthe adjacent cell.If no cell satisfies S criteria, UE will take the area as dead zone and continue the PLMNselection and reselection procedure.Max(UE_TXPWR_MAX_RACH-P_MAX,0), dBmPcompensationMaximum TX power level an UE may use when accessing the cell onRACH (read in system information) (dBm)UE_TXPWR_MAX_RACHMaximum RF output power of the UE (dBm)P_MAXMinimum required RX level in the cell (dBm)QrxlevminMinimum required quality level in the cell (dB)QqualminMeasured cell RX level value. This is received signal, CPICH RSCP forcurrent cells (dBm)QrxlevmeasMeasured cell quality value. The quality of the received signal expressed inCPICH Ec/N0 (dB) for current cellQqualmeasCell RX level value (dBm)SrxlevCell quality value (dB)SqualExplanationParameters17
    • Page17Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of S CriterionQUALMEASParameter name: Cell Se-reselection quality measureRecommended value: CPICH_ECNOQQUALMINParameter name: Min quality levelRecommended value: -18, namely -18dBQUALMEASParameter name: Cell Sel-reselection quality measureValue range: CPICH_ECNO(CPICH Ec/N0),CPICH_RSCP(CPICH RSCP)Physical unit: None.Content: Cell selection and reselection quality measure, may be set to CPICH Ec/N0or CPICH RSCP.Recommended value: CPICH_ECNO.QQUALMINParameter name: Min quality levelValue range: -24~0Physical value range: -24~0; step: 1Physical unit: dBContent: The minimum required quality level corresponding to CPICH Ec/No. The UEcan camp on the cell only when the measured CPICH Ec/No is greater than the valueof this parameter.Recommended value: -18Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.18
    • Page18Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of S CriterionQRXLEVMINParameter name: Min Rx levelRecommended value: -58, namely -115dBmMAXALLOWEDULTXPOWERParameter name: Max allowed UE UL TX powerRecommended value: 21, namely 21dBmQRXLEVMINParameter name: Min Rx levelValue range: -58~-13.Physical value range: -115~-25; step: 2 (-58:-115; -57:-113; ..., -13:-25 ).Physical unit: dBm.Content: The minimum required RX level corresponding to CPICH RSCP. The UE cancamp on the cell only when the measured CPICH RSCP is greater than the value ofthis parameter.Recommended value: -58.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.MAXALLOWEDULTXPOWERParameter name: Max allowed UE UL TX powerValue range: -50~33Physical value range: -50~33; step: 1Physical unit: dBmContent: The maximum allowed uplink transmit power of a UE in the cell, which isrelated to the network planning. Content: Allowed maximum power transmitted onRACH in the cell. It is related to network planning.Recommended value: -21Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.19
    • Page19Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell ReselectionAfter selecting a cell and camping on it, the UE periodicallysearches for a better cell according to the cell reselectioncriteria. If finding such a cell, the UE selects this cell tocamp on.UE should monitor the quality of current cell and neighbor cells in order to camp on the bettercell to initiate service. The better cell is the most suitable one for the UE to camp on and obtainservices. The QoS of this cell is not necessarily more satisfying.20
    • Page20Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Measurement Start Criteria (Cont.)Intra-frequency measurementSqual ≤ Sintrasearch↓Qqualmeas − Qqualmin ≤ Sintrasearch↓Qqualmeas ≤ Qqualmin + SintrasearchParameters of the measurement start criteriaMinimum required quality level in the cell (dB) .QqualminMeasurement threshold for UE to trigger inter-RAT cell reselection,compared with Squal.SsearchRATmMeasurement threshold for UE to trigger inter-frequency cell reselection,compared with Squal.SintersearchMeasurement threshold for UE to trigger intra-frequency cell reselection,compared with Squal.SintrasearchCell quality value (dB)SqualDescriptionName21
    • Page21Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Measurement Start Criteria (Cont.)Inter-frequency measurementSqual ≤ Sintersearch↓Qqualmeas − Qqualmin ≤ Sintersearch↓Qqualmeas ≤ Qqualmin + SintersearchParameters of the measurement start criteriaMinimum required quality level in the cell (dB) .QqualminMeasurement threshold for UE to trigger inter-RAT cell reselection,compared with Squal.SsearchRATmMeasurement threshold for UE to trigger inter-frequency cell reselection,compared with Squal.SintersearchMeasurement threshold for UE to trigger intra-frequency cell reselection,compared with Squal.SintrasearchCell quality value (dB)SqualDescriptionName22
    • Page22Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Measurement Start Criteria (Cont.)Inter-RAT measurementSqual ≤ SsearchRATm↓Qqualmeas − Qqualmin ≤ SsearchRATm↓Qqualmeas ≤ Qqualmin + SsearchRATmParameters of the measurement start criteriaMinimum required quality level in the cell (dB) .QqualminMeasurement threshold for UE to trigger inter-RAT cell reselection,compared with Squal.SsearchRATmMeasurement threshold for UE to trigger inter-frequency cell reselection,compared with Squal.SintersearchMeasurement threshold for UE to trigger intra-frequency cell reselection,compared with Squal.SintrasearchCell quality value (dB)SqualDescriptionName23
    • Page23Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Measurement Start CriteriaIDLESINTRASEARCHParameter name: Intra-freq cell reselection threshold for idlemodeRecommended value: NoneCONNSINTRASEARCHParameter name: Intra-freq cell reselection threshold forconnected modeRecommended value: NoneIDLESINTRASEARCHParameter name: Intra-freq cell reselection threshold for idle modeValue range: {{-16~10},{127}} .Physical value range: -32~20; step: 2.Physical unit: dB.Content: A threshold for intra-frequency cell reselection in idle mode. When the quality(CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plusthe [Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started.Recommended value: None.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.CONNSINTRASEARCHParameter name: Intra-freq cell reselection threshold for connected modeValue range: {{-16~10},{127}} .Physical value range: -32~20; step: 2.Physical unit: dBContent: A threshold for intra-frequency cell reselection in connect mode. When thequality (CPICH Ec/No measured by UE) of the serving cell is lower than this thresholdplus the [Qqualmin] of the cell, the intra-frequency cell reselection procedure will bestarted.Recommended value: None.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.24
    • Page24Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Measurement Start CriteriaIDLESINTERSEARCHParameter name: Inter-freq cell reselection threshold for idlemodeRecommended value: NoneCONNSINTERSEARCHParameter name: Inter-freq cell reselection threshold forconnected modeRecommended value: NoneIDLESINTERSEARCHParameter name: Inter-freq cell reselection threshold for idle modeValue range: {{-16~10},{127}} .Physical value range: -32~20; step: 2.Physical unit: dB.Content: A threshold for inter-frequency cell reselection in idle mode. When the quality(CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plusthe [Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started.Recommended value: None.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.CONNSINTERSEARCHParameter name: Inter-freq cell reselection threshold for connected modeValue range: {{-16~10},{127}} .Physical value range: -32~20; step: 2.Physical unit: dBContent: A threshold for inter-frequency cell reselection in connect mode. When thequality (CPICH Ec/No measured by UE) of the serving cell is lower than this thresholdplus the [Qqualmin] of the cell, the inter-frequency cell reselection procedure will bestarted.Recommended value: None.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.25
    • Page25Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Measurement Start CriteriaSSEARCHRATParameter name: Inter-RAT cell reselection thresholdRecommended value: NoneSSEARCHRATParameter name: Inter-RAT cell reselection thresholdValue range: {{-16~10},{127}} .Physical value range: -32~20; step: 2.Physical unit: dB.Content: A threshold for inter-RAT cell reselection. When the quality (CPICH Ec/Nomeasured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] ofthe cell, the inter-RAT cell reselection procedure will be started.Recommended value: None.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.26
    • Page26Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Measurement Start Criteria DescriptionThe intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in thefigure.Usually, Sintrasearch > Sintersearch > SsearchRATm27
    • Page27Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell Reselection CriteriaCriterion R is used for intra-frequency, inter-frequency cellsand inter-RAT cell reselection.The cell-ranking criterion R is defined by :nsoffsetnmeasn QQR ,, −=hystssmeass QQR += ,The cells are ranked according to R criteria specified above ,deriving QQmeas,nmeas,n and QQmeas,smeas,s andcalculating R value.In Rs, s means serving cell. In Rn, n means neighbor cell.The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn. The hysteresis Qhyst1s is usedfor Qhysts to calculate Rs.If a TDD or GSM cell is ranked as the best cell, the UE shall reselect that TDD or GSM cell.If an FDD cell is ranked as the best cell and the quality measure for cell selection andreselection is set to CPICH RSCP, the UE shall reselect that FDD cell.If an FDD cell is ranked as the best cell and the quality measure for cell selection andreselection is set to CPICH Ec/N0, the UE shall perform a second ranking of the FDD cellsaccording to the R criteria specified above.In this case, however, the UE uses the measurement quantity CPICH Ec/N0 for deriving theQmeas,n and Qmeas,s and then calculating the R values of the FDD cells. The offsetQoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for Qhysts tocalculate Rs.28
    • Page28Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Hysteresis and Time IntervalTimeTreselectionQualityRnRsQmeas,nQmeas,sQhyst,sQoffsets,nIn all the previous cases, the UE can reselect a new cell only when the following conditions aremet:The new cell is better ranked than the serving cell during a time interval Treselection.More than one second has elapsed since the UE camped on the current serving cell.29
    • Page29Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of R CriteriaIDLEQHYST1SParameter name: Hysteresis 1 for idle modeRecommended value: 2, namely 4dBCONNQHYST1SParameter name: Hysteresis 1 for connect modeRecommended value: 2, namely 4dBIDLEQHYST1SParameter name: Hysteresis 1 for idle modeValue range: 0~20.Physical value range: 0~40; step: 2.Physical unit: dB.Content: The hysteresis value in idle mode for serving FDD cells in case the qualitymeasurement for cell selection and reselection is set to CPICH RSCP. It is related tothe slow fading feature of the area where the cell is located. The greater the slowfading variance is, the greater this parameter.Recommended value: 2.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.CONNQHYST1SParameter name: Hysteresis 1 for connected modeValue range: 0~20.Physical value range: 0~40; step: 2.Physical unit: dB.Content: The hysteresis value in connect mode for serving FDD cells in case thequality measurement for cell selection and reselection is set to CPICH RSCP. It isrelated to the slow fading feature of the area where the cell is located. The greater theslow fading variance is, the greater this parameter.Recommended value: 2.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.30
    • Page30Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of R Criteria (Cont.)IDLEQHYST2SParameter name: Hysteresis 2 for idle modeRecommended value: Qhyst1s for idle modeCONNQHYST2SParameter name: Hysteresis 2 for connected modeRecommended value: Qhyst1s for connected mode.IDLEQHYST2SParameter name: Hysteresis 2 for idle modeValue range: {{0~20},{255}} .Physical value range: 0~40; step: 2.Physical unit: dB.Content: The hysteresis value in idle mode for serving FDD cells in case the qualitymeasurement for cell selection and reselection is set to CPICH Ec/No. It is related to the slowfading feature of the area where the cell is located. The greater the slow fading variance is, thegreater this parameter. It is optional. If it is not configured, [Hysteresis 1] will be adopted as thevalue.Recommended value: Qhyst1s for idle mode .Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, andmodify it through MOD CELLSELRESEL.CONNQHYST2SParameter name: Hysteresis 2 for connected modeValue range: {{0~20},{255}} .Physical value range: 0~40; step: 2.Physical unit: dB.Content: The hysteresis value in connect mode for serving FDD cells in case the qualitymeasurement for cell selection and reselection is set to CPICH RSCP. It is related to the slowfading feature of the area where the cell is located. The greater the slow fading variance is, thegreater this parameter.Recommended value: Qhyst1s for connected mode. .Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, andmodify it through MOD CELLSELRESEL.31
    • Page31Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of R Criteria (Cont.)TRESELECTIONSParameter name: Reselection delay timeRecommended value: 1, namely 1s.TRESELECTIONSParameter name: Reselection delay timeValue range: 0~31 .Physical value range: 0~31; step: 1.Physical unit: s.Content: If the signal quality of a neighboring cell is better than the serving cell duringthe specified time of this parameter, the UE will reselect the neighboring cell. It is usedto avoid ping-pong reselection between different cells. Note: The value 0 correspondsto the default value defined in the protocol.Recommended value: 1.Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL.32
    • Page32Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of R Criteria (Cont.)IDLEQOFFSET1SNParameter name: IdleQoffset1snRecommended value: 0, namely 0dB.CONNQOFFSET1SNParameter name: ConnQoffset1snRecommended value: 0, namely 0dB.IDLEQOFFSET1SNParameter name: IdleQoffset1snOffset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is inidle modeValue range: -50 to +50 .Physical value range: -50 to +50; step: 1.Physical unit: dB.Content: This parameter is used for moving the border of a cell. The larger the value of thisparameter, the lower the probability of neighboring cell selection.Recommended value: 0.Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query itthrough LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MODINTRAFREQNCELL / MOD INTERFREQNCELL.CONNQOFFSET1SNParameter name: ConnQoffset1snOffset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is inconnected modeValue range: -50 to +50 .Physical value range: -50 to +50 ; step: 1.Physical unit: dB.Content: This parameter is used for moving the border of a cell. The larger the value of thisparameter, the lower the probability of neighboring cell selection.Recommended value: 0.Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query itthrough LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MODINTRAFREQNCELL / MOD INTERFREQNCELL.33
    • Page33Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of R Criteria (Cont.)IDLEQOFFSET2SNParameter name: IdleQoffset2snRecommended value: 0, namely 0dB.CONNQOFFSET2SNParameter name: ConnQoffset2snRecommended value: 0, namely 0dB.IDLEQOFFSET2SNParameter name: IdleQoffset2snOffset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is inidle modeValue range: -50 to +50 .Physical value range: -50 to +50; step: 1.Physical unit: dB.Content: This parameter is used for moving the border of a cell. The larger the value of thisparameter, the lower the probability of neighboring cell selection.Recommended value: 0.Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query itthrough LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MODINTRAFREQNCELL / MOD INTERFREQNCELL.CONNQOFFSET2SNParameter name: ConnQoffset2snOffset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is inconnected modeValue range: -50 to +50 .Physical value range: -50 to +50 ; step: 1.Physical unit: dB.Content: This parameter is used for moving the border of a cell. The larger the value of thisparameter, the lower the probability of neighboring cell selection.Recommended value: 0.Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query itthrough LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MODINTRAFREQNCELL / MOD INTERFREQNCELL.34
    • Page34Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure35
    • Page35Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Location RegistrationThe location registration includes:Location update (for non-GPRS)Route update (for GPRS)The location registration is used for the PLMN to trace the current status of the UE and toensure that the UE is connected with the network when the UE does not perform any operationfor a long period.36
    • Page36Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Periodic Location RegistrationPeriodic location registration is controlled by a PeriodicLocation Update timer (T3212) or a Periodic Routing AreaUpdate timer (T3312)Periodic location registration may be used to periodically notify the network of the availability ofthe UE.T3212 is for non-GPRS operationT3312 is for GPRS operation37
    • Page37Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Location RegistrationT3212Parameter name: Periodical location update timer [6min]Recommended value: 10, namely 60minATTParameter name: Attach/detach indicationRecommended value: ALLOWEDT3212Parameter name: Periodical location update timer [6min]Value range: 0~255.Physical unit: 6 min.Content: This parameter indicates the time length of the periodical location update.Periodical location update is implemented by MS through the location updateprocedure. 0: The periodical update procedure is not used. This parameter is valid onlywhen [CN domain ID] is set as CS_DOMAIN.Recommended value: 10.Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN,modify it through MOD CNDOMAIN.ATTParameter name: Attach/detach indicationValue range: NOT_ALLOWED, ALLOWED .Content: NOT_ALLOWED indicates that MS cannot apply the IMSI attach/detachprocedure. ALLOWED indicates that MS can apply the IMSI attach/detach procedure.This parameter is valid only when [CN domain ID] is set as CS_DOMAIN.Recommended value: ALLOWED.Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN,modify it through MOD CNDOMAIN.38
    • Page38Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure39
    • Page39Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Paging InitiationCN initiated pagingEstablish a signaling connectionUTRAN initiated pagingTrigger the cell update procedureTrigger reading of updated system informationFor CN originated paging:In order to request UTRAN connect to UE, CN initiates the paging procedure,transmits paging message to the UTRAN through Iu interface, and UTRAN transmitsthe paging message from CN to UE through the paging procedure on Uu interface,which will make the UE initiate a signaling connection setup process with the CN.For UTRAN originated paging:When the cell system message is updated: When system messages change, theUTRAN will trigger paging process in order to inform UE in the idle, CELL_PCH orURA_PCH state to carry out the system message update, so that the UE can read theupdated system message.UE state transition: In order to trigger UE in the CELL_PCH or URA_PCH state tocarry out state transition (for example, transition to the CELL_FACH state), the UTRANwill perform a paging process. Meanwhile, the UE will initiate a cell update or URAupdate process, as a reply to the paging.40
    • Page40Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Paging Type 1If UE is in CELL_PCH,URA_PCH or IDLE state,the pagingmessage will be transmitted on PCCH with paging type 1CN RNC1 RNC2 NODEB1.1 NODEB2.1 UERANAPRANAPRANAP RANAPPCCH: PAGING TYPE 1PAGINGPAGINGPCCH: PAGING TYPE 1Paging type 1:The message is transmitted in one LA or RA according to LAI or RAI.After calculating the paging time, the paging message will be transmitted at that timeIf UE is in CELL_PCH or URA_PCH state, the UTRAN transmits the paginginformation in PAGING TYPE 1 message to UE. After received paging message, UEperforms a cell update procedure to transit state to CELL_FACH.As shown in the above figure, the CN initiates paging in a location area (LA), which is coveredby two RNCs. After receiving a paging message, the RNC searches all the cells correspondingto the LAI, and then calculates the paging time, at which it will send the PAGING TYPE 1message to these cells through the PCCH.41
    • Page41Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Paging Type 2If UE is in CELL_DCH or CELL_FACH state,the pagingmessage will be transmitted on DCCH with paging type 2CN SRNC UERANAPRANAPPAGINGRRCRRCDCCH: PAGING TYPE 2Paging type 2:If UE is in CELL_DCH or CELL_FACH state,the paging message will be transmittedon DCCH with paging type 2The message will be only transmitted in a cellAs shown in the above figure, if the UE is in the CELL_-DCH or CELL_FACH state, theUTRAN will immediately transmit PAGING TYPE 2 message to the paged UE on DCCHchannel.42
    • Page42Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Typical Call Flow of UEUE NAS UE AS NSS MSCpagingAUTHENTICATION REQUESTAUTHENTICATION RESPONSERR_SECURITY_CONTROL_REQ(IK CK)Security mode controlSETUPCALL CONFIRMALERTCONNECTCONNECT ACKNOWLEDGERAB setup processpagingRR_EST_REQ (PAGING RESPONSE)RR_PAING_INDINITIAL_DIRECT_TRANSFER(PAGING RESPONSE)RANAPRANAPRRC setup processMany problems will cause the target UE cannot receive the paging message properlyPower setting of paging channel is unreasonable.Unreasonable paging strategies will result in paging channel congestion, which cancause paging message loss.Paging parameter is unreasonableEquipment fault43
    • Page43Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.DRX ProcedureUE receives the paging indicator on PICH periodically, thatis the Discontinuous Reception (DRX)The value for the DRX paging cycle length is determined asfollows: :DRX Cycle Length = (2^K)×PBP framesIn idle mode, the UE can monitor the paging in two modes: one is to decode SCCPCH directlyevery 10ms, the other is to decode the PICH periodically. The second one is the DRX, which isDiscontinuous Reception Mechanism.The paging period formula:DRX Cycle Length = (2^K)*PBP framesK is the “CN domain specific DRX cycle length coefficient”, which is broadcasted inSIB1. The typical value is 6.PBP is paging block period, which is 1 for FDD modeThe paging period should be 640ms if K is 644
    • Page44Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.DRX Procedure (Cont.)Through DRX, UE only listens to PICH at certain predefinedtime. And UE will read the paging information on SCCPCH ifthe paging indicator is 1.The value of the Paging Occasion is determined as follows:Paging Occasion (CELL SFN) ={(IMSI mod M) mod (DRX cycle length div PBP)} * PBP+ n * DRX cycle length + Frame OffsetPaging SFN formula:Paging Occasion (CELL SFN) = {(IMSI mod M) mod (DRX cycle length div PBP)}*PBP + n *DRX cycle length + Frame Offsetn =0, 1, 2……and the requirement is the calculated CELL SFN must be below itsmaximum value 4096Frame Offset is 0 for FDD modeM is the number of SCCPCH which carries PCH, and the typical value is 1The formula cloud be simplified as: SFN = IMSI mod (2^K) + n * (2^K)45
    • Page45Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.DRX Procedure (Cont.)⎣ ⎦ ⎣ ⎦ ⎣ ⎦( )( )( ) NpNpSFNSFNSFNSFNPIq mod144144mod512/64/8/18 ⎟⎟⎠⎞⎜⎜⎝⎛⎥⎦⎥⎢⎣⎢×+++×+=UE must calculate q to know which PI to monitor in oneframe of PICHThe q value is achieved by the following formula :Where, PI = (IMSI div 8192) mod NPSFN is the paging occasion of the UEAs shown in the followed figure, the UE needs to monitor the frames (paging occasions)indicated by the red dots, and then decodes the qth PI of this frame.¡ £¡ £¡ £02^K-10 4095¡ £¡ £¡ £PI PI PI PI¡ £¡ £¡ £¡ £¡ £¡ £0 1 q NP-1One DRX cycle46
    • Page46Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.DRX Procedure (Cont.)τPICHAssociated S-CCPCH framePICH frame containing paging indicatorTime offset between PICH and S-CCPCHThe timing relationship between PICH and S-CCPCH is defined by the above figure, and theinterval is 3 slots duration (2ms, 7680 chips).47
    • Page47Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of DRXDRXCYCLELENCOEFParameter name: DRX cycle length coefficientRecommended value: 6PICHMODEParameter name: PICH modeRecommended value: V36.DRXCYCLELENCOEFParameter name: DRX cycle length coefficientValue range: 6~9 .Content: This parameter is broadcasted on SIB1. This parameter is used when a UE isin idle mode.Recommended value: 6.Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, andmodify it through MOD CNDOMAIN.PICHMODEParameter name: PICH modeValue range: V18, V36, V72, V144 .Physical value range: 18, 36, 72, 144 .Content: Indicating the number of PIs contained in each frame on the PICH.Recommended value: V36 .Set this parameter through ADD PICH, query it through LST PICH.48
    • Page48Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of DRXMACCPAGEREPEATParameter name: Number of page re-TXRecommended value: 1MACCPAGEREPEATParameter name: Number of page re-TXNumber of retransmissions of paging messageValue range: 0~2 .Content: If the number of retransmissions of paging message exceeds this parametervalue, retransmissions stop.Recommended value: 1.Set this parameter through SET WFMRCFGDATA, query it through LSTWFMRCFGDATA.49
    • Page49Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. PLMN Selection2. System Information Reception3. Cell Selection and Reselection4. Location Registration5. Paging Procedure6. Access Procedure50
    • Page50Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Two Working Mode of UEIdle modeAfter turning on, UE will stay in idle modeConnected modeUE will switch to connected mode which could be CELL_FACHstate or CELL_DCH state from the idle modeAfter releasing RRC connection, UE will switch to the idlemode from the connected modeThe most important difference between idle mode and connected mode is whether UE hasRRC connection with UTRAN or not.In idle mode, UE will be identified by IMSI, TMSI or PTMSI and so on.In connected mode, UE will be identified by URNTI (UTRAN Radio Network TemporaryIdentity), which is the ID of one RRC connection.51
    • Page51Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Random Access ProcedureDefinitionRandom access procedure is initiated by UE in order to getservice from the system. Meanwhile, the access channels areallocated to the UE by systemThis process may happen in the following scenarios:Attach and detachLA update and RA updateSignaling connection for services52
    • Page52Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Random Access ChannelAICH accessslots10 ms#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4τp-a#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4PRACHaccess slotsSFN mod 2 = 0 SFN mod 2 = 110 msAccess slot set 1 Access slot set 2DefinitionUE will transmit the preamble at the access time slotEach 20ms access frame is composed of two 10ms radio frames, which is divided into 15access time slot, and 5120 chips for each slotThe PRACH access slots, AICH access slots and their time offset are showed in the abovefigure53
    • Page53Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.RACH Sub-Channels141312111098721076543614131211109855432107648141312111093765432102111098141312176543210011109876543210Random access sub-channels numberSFNmod 8The access slots of different RACH sub-channels are illustrated bythe following tableA RACH sub-channel defines a sub-set of the total set of uplink access slots. There are a totalof 12 RACH sub-channels.54
    • Page54Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Access Service ClassThe PRACH resources can be classified into several ASCs,so as to provide RACH applications with different priorities.For Frequency Division Duplex (FDD) mode, the PRACH resources include access timeslotsand preamble signatures, which can be classified into several ASCs, so as to provide RACHapplications with different priorities.The ASCs range from 0 to 7, and the quantity of ASCs is 8. "0" indicates the highest priorityand "7" indicates the lowest priority.The system will assign random access sub-channels and signatures according to the ASC(Access Service Class ) of UE.Set ASC of PRACH through ADD PRACHASC, modify it through MOD PRACHASC, andremove it through RMV PRACHASC.55
    • Page55Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Access Control“Access Control” is used by network operators to preventoverload of radio access channels under critical conditions.Access class 0~Access Class 9Access class 11~Access Class 15Access class 10The access class number is stored in the SIM/USIM.Access class 0~9 are allocated to all the users. And the 10 classes show the same priority.Access class 11~15 are allocated to specific high priority users as follows. (The enumeration isnot meant as a priority sequence):Access class 15: PLMN staffAccess class 14: users subscribing to emergency servicesAccess class 13: public organizationsAccess class 12: users subscribing to security servicesAccess class 11: users responsible for PLMN managementAccess Class 10 indicates whether or not network access for Emergency Calls is allowed forUEs with access classes 0 to 9 or without an IMSI. For UEs with access classes 11 to 15,Emergency Calls are not allowed if both "Access class 10" and the relevant Access Class (11to 15) are barred. Otherwise, Emergency Calls are allowed.56
    • Page56Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Mapping between AC and ASCThe AC-ASC mapping information is optional and used forthe System Information Block 5 (SIB5) only.Set the mapping between AC and ASC through ADD PRACHACTOASCMAP, modify itthrough MOD PRACHACTOASCMAP, and remove it through RMV PRACHACTOASCMAP.57
    • STARTChoose a RACH sub channel fromavailable onesGet available signaturesSet Preamble Retrans MaxSet Preamble_Initial_PowerSend a preambleCheck the corresponding AIIncrease message part power byp-m based on preamble powerSet physical status to be RACHmessage transmitted Set physical status to be Nackon AICH receivedChoose a access slot againCounter> 0 & Preamblepower-maximum allowed power<6 dBChoose a signature andincrease preamble transmit powerSet physical status to be Nackon AICH receivedGet negative AINo AIReport the physical status to MACENDGet positive AIThe counter of preamble retransmitSubtract-1, Commanded preamblepower increased by Power Ramp StepNYSend the correspondingmessage partRandom Access Procedure58
    • Physical random access procedure1. Derive the available uplink access slots, in the next full access slot set, for the set ofavailable RACH sub-channels within the given ASC. Randomly select one access slotamong the ones previously determined. If there is no access slot available in theselected set, randomly select one uplink access slot corresponding to the set ofavailable RACH sub-channels within the given ASC from the next access slot set. Therandom function shall be such that each of the allowed selections is chosen with equalprobability2. Randomly select a signature from the set of available signatures within the givenASC3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power5. Transmit a preamble using the selected uplink access slot, signature, and preambletransmission power6. If no positive or negative acquisition indicator (AI ≠ +1 nor –1) corresponding to theselected signature is detected in the downlink access slot corresponding to theselected uplink access slot:A: Select the next available access slot in the set of available RACH sub-channels within the given ASCB: select a signatureC: Increase the Commanded Preamble PowerD: Decrease the Preamble Retransmission Counter by one. If the PreambleRetransmission Counter > 0 then repeat from step 6. Otherwise exit thephysical random access procedure7. If a negative acquisition indicator corresponding to the selected signature isdetected in the downlink access slot corresponding to the selected uplink access slot,exit the physical random access procedure Signature8. If a positive acquisition indicator corresponding to the selected signature is detected ,Transmit the random access message three or four uplink access slots after the uplinkaccess slot of the last transmitted preamble9. Exit the physical random access procedure59
    • Page59Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.RRC Connection MessageTypical RRC connection messagesRRC_CONNECTION_REQUESTRRC_CONNECTION_SETUPRRC_CONNECTION_SETUP_COMPLETERRC_CONNECTION_RELEASEWhen a UE needs network service, it first sets up RRC connection as follows:The UE sends a RRC CONNECTION REQUEST message from the cell where itcamps to the RNC.The RNC allocates related resources for the UE and sends an RRC CONNECTIONSETUP message to the UE.The UE sends a RRC CONNECTION SETUP COMPLETE message to the RNC. TheRRC connection setup ends.60
    • Page60Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UE Timers and Constants in Idle ModeT300Parameter name: Timer 300 [ms]Recommended value: D2000, namely 2000msN300Parameter name: Constant 300Recommended value: 3T300Parameter name: Timer 300[ms]Value range: D100, D200, D400, D600, D800, D1000, D1200, D1400, D1600, D1800,D2000, D3000, D4000, D6000, D8000 .Physical value range: 100, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000,3000, 4000, 6000, 8000Physical unit: msContent: T300 is started after the UE transmits the RRC CONNECTION REQUESTmessage and stopped after the UE receives the RRC CONNECTION SETUPmessage. RRC CONNECTION REQUEST resents upon the expiry of the timer if V300less than or equal to N300. Otherwise, the UE enters idle mode.Recommended value: D2000.Set this parameter through SET IDLEMODETIMER, query it through SETIDLEMODETIMER.N300Parameter name: Constant 300Value range: 0~7 .Content: Maximum number of retransmission of RRC CONNECTION REQUEST .Recommended value: 3.Set this parameter through SET IDLEMODETIMER, query it through SETIDLEMODETIMER.61
    • Page61Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UE Timers and Constants in Idle ModeT312Parameter name: Timer 312 [s]Recommended value: 6, namely 6sN312Parameter name: Constant 312Recommended value: D1, namely 1T312Parameter name: Timer 312[s]Value range: 1~15 .Physical value range: 1~15sPhysical unit: sContent: T312 is started after the UE starts to establish a DCH and stopped when theUE detects N312 consecutive "in sync" indications from L1. It indicates physicalchannel setup failure upon the expiry of the timer.Recommended value: 6.Set this parameter through SET IDLEMODETIMER, query it through SETIDLEMODETIMER.N312Parameter name: Constant 312Value range: D1, D2, D4, D10, D20, D50, D100, D200, D400, D600, D800, D1000 .Physical value range: 1, 2, 4, 10, 20, 50, 100, 200, 400, 600, 800, 1000Content: Maximum number of consecutive "in sync" indications received from L1. .Recommended value: D1.Set this parameter through SET IDLEMODETIMER, query it through SETIDLEMODETIMER.62
    • Page62Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.RRC Connection Establish ChannelType and Bit RateRRCCAUSEParameter name: Cause of RRC connection establishmentRecommended value: noneSIGCHTYPEParameter name: Channel type for RRC establishmentRecommended value: noneRRCCAUSEParameter name: Cause of RRC connection establishmentValue range: ORIGCONVCALLEST, ORIGSTREAMCALLEST, ORIGINTERCALLEST,ORIGBKGCALLEST, ORIGSUBSTRAFFCALLEST, TERMCONVCALLEST,TERMSTREAMCALLEST, TERMINTERCALLEST, TERMBKGCALLEST,EMERGCALLEST, INTERRATCELLRESELEST, INTERRATCELLCHGORDEREST,REGISTEST, DETACHEST, ORIGHIGHPRIORSIGEST, ORIGLOWPRIORSIGEST,CALLREEST, TERMHIGHPRIORSIGEST, TERMLOWPRIORSIGEST,TERMCAUSEUNKNOWN, DEFAULTEST.Content: The cause of Rrc connection establishment. .Recommended value: none.Set this parameter through SET RRCESTCAUSE, query it through LSTRRCESTCAUSE.SIGCHTYPEParameter name: Channel type for RRC establishmentValue range: FACH, DCH_3.4K_SIGNALLING, DCH_13.6K_SIGNALLING.Content: FACH indicates that the RRC is established on the common channel.DCH_3.4K_SIGNALLING indicates that the RRC is established on the dedicatedchannel of 3.4 kbit/s. DCH_13.6K_SIGNALLING indicates that the RRC is establishedon the dedicated channel of 13.6 kbit/s. .Recommended value: none.Set this parameter through SET RRCESTCAUSE, query it through LSTRRCESTCAUSE.63
    • Page63Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.RRC Connection Establish ChannelType and Bit RateINTRAMEASCTRLParameter name: IntraMeas Ctrl Ind for RRC establishmentRecommended value: SUPPORTINTRAMEASCTRLParameter name: IntraMeas Ctrl Ind for RRC establishmentValue range: NOT_SUPPORT, SUPPORT.Content: NOT_SUPPORT indicates that the Intrafreq measurement control messagewill be send in RRC Connection Establishment. SUPPORT indicates that the Intrafreqmeasurement control will not be send in RRC Connection Establishment.Recommended value: SUPPORT .Set this parameter through SET RRCESTCAUSE, query it through LSTRRCESTCAUSE.64
    • Thank youwww.huawei.com65
    • www.huawei.comCopyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.WCDMA Power Controland Relevant Parameters263
    • Page1Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.ObjectivesUpon completion of this course, you will be able to:Describe the purpose and function of power controlExplain open loop power control and parametersExplain inner loop power control and relevant parametersExplain outer loop power control and relevant parameters264
    • Page2Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Power Control Overview2. Open Loop Power Control3. Closed Loop Power Control265
    • Page3Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Power Control Overview2. Open Loop Power Control3. Closed Loop Power Control266
    • Page4Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Purpose of Uplink Power ControlUplink Transmission CharacterSelf-interference systemUplink capacity is limited by interference levelNear-far effectFadingUplink Power Control FunctionEnsure uplink quality with minimum transmission powerDecrease interference to other UE, and increase capacitySolve the near-far effectSave UE transmission powerCDMA system have the embedded characteristics of self-interference, for uplink oneuser’s transmission power become interference to others.The more connected users, the higher interference. Generally the capacity is limited byinterference level.WCDMA suffer from Near-far effect, which means if all UE use the same transmissionpower, the one close to the NodeB may block the entire cell.Uplink power control can guarantee the service quality and minimize the requiredtransmission power. It will resolve the near-far effect and resist fading of signalpropagation. By lowering the uplink interference level, the system capacity will beincreased.267
    • Page5Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Purpose of Downlink Power ControlDownlink Transmission CharacterInterference among different subscribersInterference from other adjacent cellsDownlink capacity is limited by NodeB transmission powerFadingDownlink Power Control FunctionEnsure downlink quality with minimum transmission powerDecrease interference to other cells, and increase capacitySave NodeB transmission powerThe downlink has different characteristics from the uplink, for downlink interference iscaused by multi-path, part of one user’s power also become interference to others.Downlink power from adjacent cells also is one part of interference to the own cell.Transmission power of NodeB is shared by all users channels, so downlink capacityusually is considered to be limited by transmission power.Downlink power control also can guarantee the service quality and minimize therequired transmission power, so the capacity is maximized in case that interference islowered.268
    • Page6Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Effect of Power ControlTime (ms)0 200 400 600 800-20-15-10-505101520Relativepower(dB)Channel FadingTransmitting powerReceiving powerBecause of channel fading in mobile communication system, the radio signal isdeteriorated and fluctuated, the fast power control become one key technology to resistthis phenomenon.In this figure, the channel fading is compensated by the transmitting power, which isadjusted by the fast power control, so the receiving power is almost constant and theradio propagation condition is improved.269
    • Page7Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Power Control ClassificationOpen Loop Power ControlUplink / Downlink Open Loop Power ControlClosed Loop Power ControlUplink / Downlink Inner Loop Power ControlUplink / Downlink Outer Loop Power ControlIn WCDMA system, power control includes open loop and closed loop power control.Open loop power control is used to determine the initial transmission power, and theclosed loop power control adjusts the transmission power dynamically andcontinuously during the connection.For uplink, the UE’s transmission power is adjusted; and for downlink, the NodeB’stransmission power is adjusted.270
    • Page8Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Power Control For Physical ChannelsPower control methods are adopted for these physical channels:“√" – can be applied, “×" – not applied√×××SCH√×××PICH√×××AICH×××√PRACH√×××SCCPCH√×××PCCPCH×√√√DPCCH×√√√DPDCHOuter LoopPower ControlInner LoopPower ControlNo PowerControlClosed Loop Power ControlOpen LoopPowerControlPhysicalChannelOpen loop power control is used in two cases:1. to decide the initial transmission power of PRACH preamble.2. to decide the initial transmission power of DPCCH / DPDCH.Closed loop power control is only applied on DPCCH and DPDCHFor other common channels, power control is not applied, they will use fixedtransmission power:The PCPICH power is defined by the PCPICH TRANSMIT POWER parameteras an absolute value in dBm.All other common channels power is defined in relation with the PCPICHTRANSMIT POWER parameter, and measured in dB.271
    • Page9Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Common Physical Channel Power ParametersMAXTXPOWERParameter name: Max transmit power of cellThe recommended value is 430, namely 43dBmPCPICHPOWERParameter name: PCPICH transmit powerThe recommended value is 330, namely 33dBmMAXTXPOWERParameter name: Max transmit power of cellValue Range: 0 to 500Physical Value Range: 0dBm to 50 dBm, step 0.1dBThe recommended value is 430, namely 43dBmContent: The sum of the maximum transmit power of all DL channels in a cell.Set this parameter through ADD CELLSETUP, query it through LST CELL and modify itthrough MOD CELLPCPICHPOWERParameter name: PCPICH transmit powerValue Range: -100 to 500Physical Value Range: -10dBm to 50 dBm, step 0.1dBThe recommended value is 330, namely 33dBmContent: This parameter should be set based on the actual environment and thedownlink coverage should be guaranteed firstly. If PCPICH transmit power is configuredtoo great, the cell capacity will be decreased, for power resources is occupied bycommon channel and the interference to traffic channels is also increased.Set this parameter through ADD PCPICH, query it through LST PCPICH and modify itthrough MOD CELL272
    • Page10Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Common Physical Channel Power ParametersPSCHPOWER or SSCHPOWERParameter name: PSCH / SCCH transmit powerThe recommended value is -50, namely -5dBBCHPOWERParameter name: BCH transmit powerThe recommended value is -20, namely -2dBPSCHPOWER or SSCHPOWERParameter name: PSCH / SCCH transmit powerValue range: -350 to 150.Physical value range: -35 to 15, step 0.1dBThe recommended value is -50, namely -5dBContent: The offset between the PSCH / SSCH transmit power and PCPICH transmitpower.For PSCH Power, set it through ADD PSCH, and query it through LST PSCH; for SSCHPower, set it through ADD SSCH, and query it through LST SSCH. And modify it throughMOD CELLBCHPOWERParameter name: BCH transmit powerValue Range:-350 to 150Physical Value Range:-35 to 15 dB, step 0.1dBThe recommended value is -20, namely -2dBContent: The offset between the BCH transmit power and PCPICH transmit power.Set this parameter through ADD BCH, query it through LST BCH, and modify it throughMOD CELL273
    • Page11Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Common Physical Channel Power ParametersMAXFACHPOWERParameter name: Max transmit power of FACHThe recommended value is 10, namely 1dBPCHPOWERParameter name: PCH transmit powerThe recommended value is -20, namely -2dBMAXFACHPOWERParameter name: Max transmit power of FACHValue range : -350 to 150Physical Value Range:-35 to 15 dB, step 0.1dBThe recommended value is 10, namely 1dBContent: The offset between the FACH transmit power and PCPICH transmitpower.Set this parameter through ADD FACH, query it through LST FACH, and modifyit through MOD SCCPCHPCHPOWERParameter name: PCH transmit powerValue Range:-350 to 150Physical Value Range:-35 to 15 dB, step 0.1dBThe recommended value is -20, namely -2dBContent: The offset between the PCH transmit power and PCPICH transmitpower.Set this parameter through ADD PCH, query it through LST PCH, and modify itthrough MOD SCCPCH274
    • Page12Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Common Physical Channel Power ParametersAICHPOWEROFFSETParameter name: AICH power offsetThe default value of this parameter is -6, namely -6dBPICHPOWEROFFSETParameter name: PICH power offsetThe default value of this parameter is -7, namely -7dBAICHPOWEROFFSETParameter name: AICH power offsetValue Range: -22 to 5Physical Value Range: -22 to 5 dB, step 1dBThe default value of this parameter is -6, namely -6dBContent: The offset between the AICH transmit power and PCPICH transmitpower.Set this parameter through ADD CHPWROFFSET, query it through LSTCHPWROFFSET, and modify it through MOD AICHPWROFFSETPICHPOWEROFFSETParameter name: PICH power offsetValue Range:-10 to 5Physical Value Range:-10 to 5 dB , step 1dBThe default value of this parameter is -7, namely -7dBContent: The offset between the PICH transmit power and PCPICH transmitpower.Set this parameter through ADD CHPWROFFSET, query it through LSTCHPWROFFSET, and modify it through MOD PICHPWROFFSET275
    • Page13Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Power Control Overview2. Open Loop Power Control3. Closed Loop Power Control276
    • Page14Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Open Loop Power Control2.1 Open Loop Power Control Overview2.2 PRACH Open Loop Power Control2.3 Downlink Dedicated Channel Open Loop Power Control2.4 Uplink Dedicated Channel Open Loop Power Control277
    • Page15Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Open Loop Power Control OverviewPurposeCalculate the initial transmission power of uplink / downlink channelsPrincipleEstimates the downlink signal power loss on propagation pathPath loss of the uplink channel is related to the downlink channelApplicationOpen loop power control is applied only at the beginning of connectionsetup to set the initial power value.In downlink open loop power control, the initial transmission power is calculatedaccording to the downlink path loss between NodeB and UE.In uplink, since the uplink and downlink frequencies of WCDMA are in the samefrequency band, a significant correlation exists between the average path loss of thetwo links. This make it possible for each UE to calculate the initial transmission powerrequired in the uplink based on the downlink path loss.However, there is 90MHz frequency interval between uplink and downlink frequencies,the fading between the uplink and downlink is uncorrelated, so the open loop powercontrol is not absolutely accurate.278
    • Page16Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Open Loop Power Control2.1 Open Loop Power Control Overview2.2 PRACH Open Loop Power Control2.3 Downlink Dedicated Channel Open Loop Power Control2.4 Uplink Dedicated Channel Open Loop Power Control279
    • Page17Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control5. Downlink SynchronizationUE Node BServingRNCDCH - FPAllocate RNTISelect L1 and L2parametersRRCRRCNBAPNBAP3. Radio Link Setup ResponseNBAPNBAP2. Radio Link Setup RequestRRCRRC7. CCCH: RRC Connection Set upStart RXdescriptionStart TXdescription4. ALCAP Iub Data Transport Bearer SetupRRCRRC9. DCCH: RRC Connection Setup Complete6. Uplink SynchronizationNBAPNBAP8. Radio Link Restore IndicationDCH - FPDCH - FPDCH - FPOpen loop powercontrol of PRACH1. CCCH: RRC Connection RequestIn access procedure, the first signaling “RRC CONNECTION REQUEST” istransmitted in message part on PRACH.Before PRACH message part transmission, UE will transmit PRACH preamble, andthe transmission power of first preamble is calculated by this PRACH open loop powercontrol.280
    • Page18Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power ControlInitial Power Calculation for the First PreambleWhen UE needs to set up a RRC connection, the initial powerof uplink PRACH can be calculated according to the followingformula:PowerTxInitialgCalculatinForValueConstant+ceInterferenUL+CPICH_RSCP-PowerTransmitPCPICH=ernitial_PowPreamble_IIn this formula, wherePCPICH TRANSMIT POWER defines the PCPICH transmit power in a cell. It isbroadcast in SIB5.CPICH_RSCP means received signal code power, the received powermeasured on the PCPICH. The measurement is performed by the UE.UL interference is the UL RTWP measured by the NodeB. It is broadcast in SIB7.CONSTANT VALUE compensates for the RACH processing gain. It is broadcastin SIB5.The initial value of PRACH power is set through open loop power control. UE operationsteps are as follows:1. Read “Primary CPICH DL TX power”, “UL interference” and “Constant value”from system information.2. Measure the value of CPICH_RSCP;3. Calculate the Preamble_Initial_Power of PRACH.281
    • Page19Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control ParametersCONSTANTVALUEParameter name: Constant value for calculating initial TXpowerThe recommended value is -20, namely -20dBCONSTANTVALUEParameter name: Constant value for calculating initial TX powerValue range : -35 ~ -10Physical Value Range:-35 to -10 dBContent: It is used to calculate the transmit power of the first preamble in therandom access process.Recommended value: -20Set this parameter through ADD PRACHBASIC, query it through LST PRACH,and modify it through MOD PRACHUUPARAS282
    • Page20Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power ControlTiming relationship of PRACH and AICHAICHPRACH1 access slotτ p-aτ p-mτp-pPre-amblePre-ambleMessagepartAcq.Ind.After UE transmit the first Preamble on PRACH, it will wait for the corresponding AI(Acquisition Indicator) on the AICH. The timing relationship of PRACH and AICH isshown in above figure.There will be 3 parameters used to define the timing relationship:τp-p: time interval between two PRACH preambles. τp-p is not a fixed value, it isdecided by selecting access slot of PRACH preambles,Here τp-p has one restriction, it must be longer than a minimum value τp-p min ,namely τp-p ≥ τp-p min.τp-a: time interval between PRACH preamble and AICH Acquisition Indicator. IfUE sends the PRACH preamble, it will detect the responding AI after τp-a time.τp-m: time interval between PRACH preamble and PRACH message part. If UEsends the PRACH preamble and receives positive AI from the AICH, it will sendthe message part after τp-m time.283
    • Page21Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control ParametersAICHTXTIMINGParameter name: AICH transmission timingContent:When AICHTXTIMING = 0,τp-p,min = 15360 chips, τp-a = 7680 chips, τp-m = 15360 chipsWhen AICHTXTIMING = 1,τp-p,min = 20480 chips, τp-a = 12800 chips, τp-m = 20480 chipsThe recommended value is 1Parameter AICHTXTIMING is used to define the set of τp-p min, τp-a, τp-m.AICHTXTIMINGParameter name: AICH transmission timingValue range:0,1Content:When AICHTXTIMING = 0,τp-p,min = 15360 chips, τp-a = 7680 chips, τp-m = 15360 chipsWhen AICHTXTIMING = 1,τp-p,min = 20480 chips, τp-a = 12800 chips, τp-m = 20480 chipsRecommended value: 1Set this parameter through ADD AICH, query it through LST AICH, and modify itneeds de-activated the cell through DEA CELL. After the old configuration ofAICH is deleted through RMV AICH , a new AICH can be established throughADD AICH284
    • Page22Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power ControlPower Ramping for Preamble RetransmissionPower Ramp StepPower Offset Pp-mPreamble_Initial_PowerMessagepartPre-amblePre-amble……Pre-amblePre-amble#1 #3 #N#2After UE transmit the first Preamble,If no positive or negative AI on AICH is received after τp-a time,UE shall increase the preamble power by POWER RAMP STEP, andretransmit the preamble.This ramping process stops until the number of transmitted preambles hasreached the MAX PREAMBLE RETRANSMISSION within an access cycle,or when the maximum number of access cycles has reached MAXPREAMBLE LOOP.If a negative AI on AICH is received by the UE after τp-a time,which indicates rejection of the preamble, the UE shall wait for a certain“Back-off Delay” and re-initiate a new random access process.When a positive AI on AICH is received by UE after τp-a time,it will transmit the random access message after the uplink access slot ofthe last preamble.The transmit power of the random access message control part should bePOWER OFFSET higher than the power of the last transmitted preamble.285
    • Page23Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control ParametersPOWERRAMPSTEPParameter name: Power increase stepThe recommended value is 2, namely 2dBPREAMBLERETRANSMAXParameter name: Max preamble retransmissionThe Recommended value is 20POWERRAMPSTEPParameter name: Power increase stepValue range : 1 to 8Physical Value Range: 1 to 8 dBContent: The power increase step of the random access preambles transmittedbefore the UE receives the acquisition indicator in the random access process.Recommended value: 2Set this parameter through ADD PRACHBASIC, query it through LST PRACH,and modify it through MOD PRACHUUPARASPREAMBLERETRANSMAXParameter name: Max preamble retransmissionValue range : 1 to 64Content: The maximum number of preambles transmitted in a preamble rampingcycle.Recommended value: 20Set this parameter through ADD PRACHBASIC, query it through LST PRACH,and modify it through MOD PRACHUUPARAS286
    • Page24Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control ParametersMMAXParameter name: Max preamble loopThe recommended value is 8NB01MIN / NB01MAXParameter name: Random back-off lower / upper limitThe recommended value: 0 for both NB01MIN / NB01MAXMMAXParameter name: Max preamble loopValue range: 1 to 32Content: The maximum number of random access preamble loops.Recommended value: 8Set this parameter through ADD RACH, query it through LST RACH, and modifyit first de-activated the cell through DEA CELL, then MOD RACH.NB01MIN / NB01MAXParameter name: Random back-off lower / upper limitValue range: 0 to 50Content: The lower / upper limit of random access back-off delay.The recommended value: 0 for both NB01MIN / NB01MAXSet this parameter through ADD RACH, query it through LST RACH, and modifyit first de-activated the cell through DEA CELL, then MOD RACH.287
    • Page25Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.PRACH Open Loop Power Control ParametersPOWEROFFSETPPMParameter name: Power offsetThe default value:-3dB for signalling transmission;-2dB for service transmission.POWEROFFSETPPMParameter name: Power offsetValue range: -5 to 10dBContent: The power offset between the last access preamble and the messagecontrol part. The power of the message control part can be obtained by addingthe offset to the access preamble power.The recommended value of this parameter is -3dB for signalling transmission ,and that -2dB for service transmissionSet this parameter through ADD PRACHTFC, query it through LST PRACH, andmodify it de-activated the cell through DEA CELL . After the old configuration ofPRACH is deleted through RMV PRACHTFC , a new parameters can beestablished through ADD PRACHTFCThe PRACH message also consists of control part and data part, here the POWEROFFSET is the difference between the PRACH preamble and the message control part.The PRACH message uses GAIN FACTOR to set the power of control / data part:GAIN FACTOR BETAC ( βc ) is the gain factor for the control part.GAIN FACTOR BETAD ( βd ) is the gain factor for the data part.288
    • Page26Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Open Loop Power Control2.1 Open Loop Power Control Overview2.2 PRACH Open Loop Power Control2.3 Downlink Dedicated Channel Open Loop Power Control2.4 Uplink Dedicated Channel Open Loop Power Control289
    • Page27Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.DL DPDCH Open Loop Power Control5. Downlink SynchronizationUE Node BServingRNCDCH - FPAllocate RNTISelect L1 and L2parametersRRCRRCNBAPNBAP3. Radio Link Setup ResponseNBAPNBAP2. Radio Link Setup RequestRRCRRC7. CCCH: RRC Connection Set upStart RXdescriptionStart TXdescription4. ALCAP Iub Data Transport Bearer SetupRRCRRC9. DCCH: RRC Connection Setup Complete6. Uplink SynchronizationNBAPNBAP8. Radio Link Restore IndicationDCH - FPDCH - FPDCH - FP1. CCCH: RRC Connection RequestDL DPDCH OpenLoop Power ControlAccording to the RRC connection establishment procedure, after RNC received the“RRC CONNECTION REQUEST” message, and NodeB set up the radio link for UE,then Iub interface resources is established between NodeB and RNC.When DCH-FP of Iub interface finished downlink and uplink synchronization, thedownlink DPCH starts to transmit, and DPDCH initial transmission power is calculatedthrough open loop power control.290
    • Page28Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.DL DPDCH Open Loop Power ControlWhen a dedicated channel is set up, the initial power ofdownlink DPDCH can be calculated according to thefollowing formula:⎟⎟⎠⎞⎜⎜⎝⎛−××= TotalCPICHCPICHDLInitial P)No/Ec(P)NoEb(WRP αIn this formula, whereR is the requested data bitrate by the userW is the chip rate(Eb/No)DL is the Eb/No target to ensure the service quality. RNC searches forthe (Eb/No)DL dynamically in a set of pre-defined values according to specific cellenvironment type, coding type, bitrate, BLER target and etc.(Ec/Io)CPICH is the CPICH signal quality measured by UE, then it is sent to RNCthrough RACH.α is the orthogonality factor in the downlink. In Huawei implementation, α is setto 0.Ptotal is the total carrier transmit power measured at the NodeBThe initial transmission power of downlink DPDCH could be calculated through thisformula, then, initial transmission power of downlink DPCCH can be obtainedaccording to the power offset: PO1, PO2 and PO3.291
    • Page29Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.DL DPDCH Open Loop Power ControlData1 TPC TFCI Data2 PilotDownlinkTransmitPowerDPCCHDPDCH DPDCH DPCCHPO2PO1PO31 timeslotThis figure shows the power offset of downlink DPCH :PO1 is the power offset of DPCCH TFCI bits to DPDCH data bits.PO2 is the power offset of DPCCH TPC bits to DPDCH data bits.PO3 is the power offset of DPCCH Pilot bits to DPDCH data bits.The values of PO1, PO2 and PO3 are configured on RNC.292
    • Page30Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.DL DPDCH Open Loop Power Control ParameterTFCIPOParameter name: TFCI power offsetThe recommended value is 0, namely 0dBTPCPOParameter name: TPC power offsetThe recommended value is 12, namely 3dBTFCIPOParameter name: TFCI power offsetValue range : 0 to 24Physical value range: 0 to 6 dB, step: 0.25Content: The offset of TFCI bit transmit power from data bit transmit power ineach time slot of radio frames on DL DPCHRecommended value: 0Set this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRCTPCPOParameter name: TPC power offsetValue range : 0 to 24Physical value range: 0 to 6 dB, step: 0.25Content: The offset of TPC bit transmit power from data bit transmit power ineach time slot of radio frames on DL DPCHRecommended value: 12Set this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRC293
    • Page31Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.DL DPDCH Open Loop Power Control ParameterPILOTPOParameter name: Pilot power offsetThe recommended value is 12, namely 3dBPILOTPOParameter name: Pilot power offsetValue range : 0 to 24Physical value range: 0 to 6 dB, step: 0.25Content: The offset of pilot bit transmit power from data bit transmit power ineach time slot of radio frames on DL DPCHThe recommended value is 12, namely 3dBSet this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRC294
    • Page32Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Power Control RestrictionThe power of downlink dedicated channel is limited by anupper and lower limit for each radio link.The DL DPDCH power could not exceed Maximum_DL_Power,nor could it be below Minimum_DL_Power.RLMAXDLPWR / RLMINDLPWRParameter name: RL Max / Min DL TX powerThe recommended value is shown in the following table.Note: Both downlink open loop and close loop power control will be limited by this parameter.RLMAXDLPWRParameter name: RL Max DL TX powerValue range : -350 to 150Physical Value Range:-35 to 15 dB, step 0.1dBContent: The maximum downlink transmit power of radio link. This parameter shouldfulfill the coverage requirement of the network planning, and the value is relative to[PCPICH transmit power]Set this parameter through ADD CELLRLPWR , query it through LST CELLRLPWR, andmodify it through MOD CELLRLPWRRLMINDLPWRParameter name: RL Min DL TX powerValue range : -350 to 150Physical Value Range:-35 to 15 dB, step 0.1dBContent: The minimum downlink transmit power of radio link. This parameter shouldconsider the maximum downlink transmit power and the dynamic range of power control,and the value is relative to [PCPICH transmit power].Since the dynamic range of power control is set as 15dB, this parameter isrecommended as [RL Max DL TX power] – 15 dB.Set this parameter through ADD CELLRLPWR, query it through LST CELLRLPWR, andmodify it through MOD CELLRLPWR295
    • Page33Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Power Restriction ParametersReferential configurations for typical services:8-114384 kbps8-132256 kbps16-150144 kbps32-17-264 kbps64-19-432 kbps128-23-88 kbpsPS Domain32-15064 kbps32-15056 kbps64-17-232 kbps64-17-228 kbps128-18-312.2 kbps AMRCS DomainDownlink SFRL Min DownlinkTransmit PowerRL Max DownlinkTransmit PowerService296
    • Page34Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Open Loop Power Control2.1 Open Loop Power Control Overview2.2 PRACH Open Loop Power Control2.3 Downlink Dedicated Channel Open Loop Power Control2.4 Uplink Dedicated Channel Open Loop Power Control297
    • Page35Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.UL DPCCH Open Loop Power Control5. Downlink SynchronizationUE Node BServingRNCDCH - FPAllocate RNTISelect L1 and L2parametersRRCRRCNBAPNBAP3. Radio Link Setup ResponseNBAPNBAP2. Radio Link Setup RequestRRCRRC7. CCCH: RRC Connection Set upStart RXdescriptionStart TXdescription4. ALCAP Iub Data Transport Bearer SetupRRCRRC9. DCCH: RRC Connection Setup Complete6. Uplink SynchronizationNBAPNBAP8. Radio Link Restore IndicationDCH - FPDCH - FPDCH - FP1. CCCH: RRC Connection RequestOpen Loop PowerControl of UL DPCCHAccording to the RRC connection establishment procedure, after RNC sent the “RRCCONNECTION SETUP” message, UE will try to synchronize with NodeB, and theuplink DPCCH starts to transmit, here DPCCH initial transmission power is calculatedthrough open loop power control298
    • Page36Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.UL DPCCH Open Loop Power ControlThe initial power of the uplink DPCCH can be calculatedaccording to the following formula:WhereCPICH_RSCP means the received signal code power, the receivedpower measured on the CPICH.DPCCH_Power_Offset is provided by RNC to the UE via RRCsignaling.RSCP_CPICHOffset_Power_DPCCHPower_Initial_DPCCH −=For Huawei, DPCCH_Power_Offset is calculated with the following formula:WherePCPICH Transmit Power defines the PCPICH transmit power in a cell.UL Interference is the UL RTWP measured by the NodeB.Default Constant Value reflects the target Ec/No of the uplink DPCCHpreamble.ValuettanConsDefaultceInterferenULPowerTransmitPCPICHOffset_Power_DPCCH++=299
    • Page37Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.UL DPCCH Open Loop Power Control ParameterDEFAULTCONSTANTVALUEParameter name: Constant value configured by defaultThe recommended value is -27, namely -27dB.DEFAULTCONSTANTVALUEParameter name: Constant value configured by defaultValue range : -35 to -10 , unit :dBContent: This parameter is used to obtain DPCCH_Power_Offset, which is usedby UE to calculate the initial transmit power of UL DPCCH during the open looppower control process.Recommended value: -27Set this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRC300
    • Page38Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Power Control RestrictionDuring the operation of uplink power control, the UEtransmit power shall not exceed the Maximum AllowedUplink Transmit Power.MAXALLOWEDULTXPOWERParameter name: Max allowed UE UL TX powerThe recommended value is 21, namely 21 dBm.MAXALLOWEDULTXPOWERParameter name: Max allowed UE UL TX powerValue range: -50 to 33Physical value range: -50 to 33 dBm. Step: 1Content: The maximum allowed uplink transmit power of a UE in the cell, whichis related to the network planning.Recommended value: 21Set this parameter through ADD CELLSELRESEL, query it through LSTCELLSELRESEL, and modify it through MOD CELLSELRESEL301
    • Page39Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Power Control RestrictionIn addition, there are four parameters which correspond to the maximumallowed transmit power of four classes of services respectively:MAXULTXPOWERFORCONVParameter name: Max UL TX power of Conversational serviceMAXULTXPOWERFORSTRParameter name: Max UL TX power of Streaming serviceMAXULTXPOWERFORINTParameter name: Max UL TX power of Interactive serviceMAXULTXPOWERFORBACParameter name: Max UL TX power of Background serviceThe recommended value is 24, namely 24 dBm.MAXULTXPOWERFORCONVParameter name: Max UL TX power of Conversational serviceMAXULTXPOWERFORSTRParameter name: Max UL TX power of Streaming serviceMAXULTXPOWERFORINTParameter name: Max UL TX power of Interactive serviceMAXULTXPOWERFORBACParameter name: Max UL TX power of Background serviceValue range: -50 to 33Physical value range: -50 to 33 dBm. Step: 1Content: The maximum UL transmit power for specific service in the cell, whichis related to the network planning.Recommended value: 24Set this parameter through ADD CELLCAC, query it through LST CELLCAC,and modify it through MOD CELLCAC302
    • Page40Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Power Control Overview2. Open Loop Power Control3. Closed Loop Power Control303
    • Page41Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Closed Loop Power Control3.1 Closed Loop Power Control Overview3.2 Uplink Inner Loop Power Control3.3 Downlink Inner Loop Power Control3.4 Outer Loop Power Control304
    • Page42Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Closed Loop Power Control OverviewWhy closed loop power control is needed?Open loop power control is not accurate enough, it can onlyestimate the initial transmission power.Closed loop power control can guarantee the QoS withminimum power. By decreasing the interference, the systemcapacity will be increased.Inner LoopOuter LoopSIRtarSIRmea>SIRtar→ TPC=0SIRmea<SIRtar→ TPC=1UntilSIRmea=SIRtarTPCBLERtarBLERmea>BLERtar→SIRtarBLERmea<BLERtar→SIRtarUntilBLERmea=BLERtarTPC=1 PowerTPC=0 PowerInner Loop Power ControlThe receiver compares SIRmea (measured SIR) with SIRtar (target SIR), and decide the TPC tosend.If SIRmea is greater than SIRtar, the TPC is set as “0” to increase transmission powerIf SIRmea is less than SIRtar, the TPC is set as “1” to decrease transmission powerTPC is sent to the transmitter in DPCCH, the transmitter will adjust the power according to thevalue of received TPC.Through inner loop power control, the SIRmea can be ensured to approach SIRtar.Outer Loop Power ControlThe receiver compares BLERmea (measured BLER) with BLERtar (target BLER), and decide howto set the SIRtar.If BLERmea is greater than BLERtar, the SIRtar is increasedIf BLERmea is less than BLERtar, the SIRtar is decreasedThe adjusted SIRtar is sent for the inner loop power control, then it will be used in previousprocess to guide the transmitter power adjustment.Through outer loop power control, the BLERmea can be ensured to approach BLERtar.305
    • Page43Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Closed Loop Power Control3.1 Closed Loop Power Control Overview3.2 Uplink Inner Loop Power Control3.3 Downlink Inner Loop Power Control3.4 Outer Loop Power Control306
    • Page44Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop Power ControlNodeB compares the measured SIR to the preset target SIR, then derivesTPC and sends the TPC Decision to UE.TPC Decision( 0, 1 )Generate TPC_cmd( -1, 0, 1 )Adjust DPCCH Tx△DPCCH =△TPC×TPC_cmdSingle RL / Soft HOPCA1 / PCA2Adjust DPDCH Tx( βc , βd )NodeB UETransmit TPCInner LoopSet SIRtarCompare SIRmea with SIRtarSIRmea > SIRtar → TPC = 0SIRmea ≤ SIRtar → TPC = 1RNC sends SIRtar (target SIR) to NodeB and then NodeB compares SIRmea (measuredSIR) with SIRtar once every timeslot.If the estimated SIR is greater than the target SIR, NodeB sends TPC “0” to UEon downlink DPCCH TPC field.Otherwise, NodeB sends TPC “1” to UE.After reception of one or more TPC in a slot, UE shall derive a single TPC_cmd (TPCcommand, with value among -1,0,1):For UE is in soft handover state, more than one TPC is received in a slot, sofirstly multiple TPC_cmd is combined.Two algorithms could be used by the UE for deriving the TPC_cmd, those arePCA1 and PCA2 (PCA means Power Control Algorithm).When deriving the combined TPC_cmd, UE shall adjust the transmit power of uplinkDPCCH with a step “UL Closed Loop Power Control Step Size“, as following:△DPCCH =△TPC×TPC_cmdThis adjustment is executed on the DPCCH, then associated DPDCH transmit poweris calculated according to DPDCH / DPCCH power ratio βd / βc.307
    • Page45Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop PCA1 with Single Radio LinkFor single radio link and PCA1, UE derives one TPC_cmd in eachtime slot as follows:0110110110…… ………… ……TPC_cmdTPC-111-111-111-1This control is performed in each time slot, sothe power control frequency is 1500HzWhen UE has single radio link, only one TPC will be received in each slot. In this case,the value of TPC_cmd shall be derived by PCA1 as follows:If the received TPC is equal to 0, then TPC_cmd for that slot is –1.If the received TPC is equal to 1, then TPC_cmd for that slot is 1.According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,and the control is performed once in each time slot, so the frequency of uplink innerloop PCA1 is 1500Hz.308
    • Page46Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop PCA2 with Single Radio LinkFor single radio link and PCA2, UE derives one TPC_cmd in each5-slot group as follows:This control is performed in each 5-slot group,so the power control frequency is 300Hz110111111100000TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS010ms radio frameGroup 2Group 1 Group 3…… ……0000010000-10000TPCTPC_cmd…… ……When UE has single radio link, only one TPC will be received in each slot. In this case,the value of TPC_cmd shall be derived by PCA2 as follows:For the first 4 slots of a set, TPC_cmd = 0.For the fifth slot of a set, UE make the decisions on as follows:If all 5 TPC within a group are 1, then TPC_cmd = 1 in the 5th slot.If all 5 TPC within a group are 0, then TPC_cmd = -1 in the 5th slot.Otherwise, TPC_cmd = 0 in the 5th slot.According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,and the control is performed once in each 5-slot group, so the frequency of uplink innerloop PCA2 is 500Hz.309
    • Page47Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop with Soft HandoverWhen UE enters soft handover state, on the NodeB side,there are two phases :Uplink synchronization phaseMulti-radio link phaseOn UE side, UE will receive different TPCs from differentRLS in one time slot. Therefore, the UE should combine allthe TPCs to get a unique TPC_CMD.On the NodeB side, there are two phases during the soft handover state:Uplink synchronization phaseThe NodeB should send durative “TPC = 1” to the newly-added RL beforesuccessful synchronization.Multi-radio link phaseEach NodeB and each cell will estimate the SIR individually and the generalTPC individually. Therefore, the UE may receive different TPC from differentRLS.Especially, when UE is in softer handover state, it means UE has radio links to thesame NodeB, in this case, these RLs (Radio Link) belong to the same RLS (Radio LinkSet), and the all TPCs are the same from each RL.310
    • Page48Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop PCA1 with Soft HandoverFor each slot, combine TPC fromthe same RLS, then get WiCELL1 CELL2CELL4CELL3RL1-1 RL1-2RLS1RLS2 RLS3Get TPC_cmd based onTPC_cmd = γ (W1, W2, … WN)0110110110…… ……RLS1-TPC (W1)…… ……RLS2-TPC (W2) 1010101101…… ………… ……TPC_cmd1101100100-1-1-1-11-1-11-1-1RLS3-TPC (W3)When UE is in soft handover state, multiple TPC will be received in each slot fromdifferent cells in the active set. UE will generate the TPC_cmd by PCA1 as follows:1. Combine the TPC from the same RLS and derive the WiWhen the RLs (Radio Link) are in the same RLS (Radio Link Set), they willtransmit the same TPC in a slot. In this case, the TPCs from the same RLS shallbe combined into one.After combination, UE will obtain a soft symbol decision Wi for each RLSi.2. Combine the TPC from different RLSs and derive the TPC_cmdUE derives TPC_cmd, it is based on a function γ and all the N soft symboldecisions Wi:TPC_cmd = γ (W1, W2, … WN),Where TPC_cmd can only take the values 1 or -1.In Huawei implementation, the function γ shall fulfil the following criteria:If the TPCs from all RLSs are “1”, the output of γ shall be equal to “1” ;If one TPC from any RLS is “0”, the output of γ shall be equal to “-1”.311
    • Page49Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop PCA2 with Soft HandoverCombine TPC from same RLSin each time slotCalculate TPC_cmdIf any TPC_tempi = -1, TPC_cmd = -1If , TPC_cmd = 1Otherwise, TPC_cmd = 0Calculate TPC_tempi for each RLSi5.0_11>∑=NiitempTPCNCELL1 CELL2CELL4CELL3RL1-1 RL1-2RLS1RLS2 RLS3When UE is in soft handover state, multiple TPC will be received in each slot fromdifferent cells in the active set. UE will generate the TPC_cmd by PCA2 as follows:1. Combine the TPC from the same RLS.When the RLs are in the same RLS, they will transmit the same TPC in a slot. Inthis case, the TPCs from the same RLS shall be combined into one.2. Calculate the TPC_tempi for each RLSUE derives TPC_tempi through the same way in the last slide, as follows:For the first 4 slots of a group, TPC_tempi = 0.For the 5th slot of a group:If all 5 TPCs within a group are 1, then TPC_tempi = 1 in the 5th slot.If all 5 TPCs within a group are 0, then TPC_tempi = -1 in the 5th slot.Otherwise, TPC_tempi = 0 in the 5th slot.3. Calculate the TPC_cmdUE derives TPC_cmd through the following criteria:If any TPC_tempi is equal to -1, TPC_cmd is set to -1.If , TPC_cmd = 1Otherwise, TPC_cmd = 05.0temp_TPCN1 N1ii >∑=312
    • Page50Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop PCA2 with Soft HandoverRLS3RLS2RLS1 100100000000100100110000011111111110000011111TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0…… ……10ms/frameGroup 1 Group 2 Group 3RLS3RLS2RLS1 00000-100000000000000-100001000010000-1000010000TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0…… ……TPCTPC_tempi00000-1000010000TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0…… ……TPC_cmdThe example of the uplink inner loop PCA2 in soft handover state.313
    • Page51Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Inner Loop Power Control ParametersPWRCTRLALGParameter name: Power control algorithm selectionThe recommended value is ALGORITHM1ULTPCSTEPSIZEParameter name: UL closed loop power control step sizeThe recommended value is 1, namely 1dBPWRCTRLALGParameter name: Power control algorithm selectionValue range: ALGORITHM1, ALGORITHM2Content: This parameter is used to inform the UE of the method for translatingthe received TPC commands.Recommended value: ALGORITHM1Set this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRCULTPCSTEPSIZEParameter name: UL closed loop power control step sizeValue range :1dB, 2dBContent: The step size of the closed loop power control performed on ULDPDCH. This parameter is mandatory when the parameter “Power controlalgorithm selection” is set as "ALGORITHM1".Recommended value: 1Set this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRC314
    • Page52Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Closed Loop Power Control3.1 Closed Loop Power Control Overview3.2 Uplink Inner Loop Power Control3.3 Downlink Inner Loop Power Control3.4 Outer Loop Power Control315
    • Page53Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power ControlUE L1 compares the measured SIR to the preset target SIR, then derivesTPC and sends the TPC Decision to NodeB.Derive TPCest(k)( 0, 1 )Generate PTPC(k)Calculate P(k)Adjust DPCH Tx PowerDPC_MODENodeBL3 Set SIRtarDerive and transmitTPC based onDPC_MODEInner LoopUEL1 compareSIRmea withSIRtarBasically the downlink inner loop power control process is similar with uplink, UE L3sends SIRtar to UE L1 and then UE L1 compares SIRmea with SIRtar :If the SIRmea is greater than the SIRtar , UE sends TPC “0” to NodeB on uplinkDPCCH TPC field.Otherwise, UE sends TPC “1” to NodeB.The UE shall check the downlink power control mode before generating the TPC, twoalgorithm DPC_MODE1 and DPC_MODE2 could be used by UE to derive the TPC.Upon receiving the TPC, NodeB shall estimate the transmitted TPC and adjust itsdownlink DPCCH/DPDCH power accordingly.After reception of one or more TPC in a slot, NodeB shall derive the estimated TPCTPCest(k) and calculate a PTPC(k), the power adjustment of k:th slot.Then NodeB shall adjust the current downlink power P(k-1) to a new power P(k), andadjust the power of the DPCCH and DPDCH with the same amount, since powerdifference between them is fixed.316
    • Page54Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power Control ModeTwo DPC_MODE (Downlink Power Control Mode) could beused:If DPC_MODE = 0, UE sends a unique TPC in each slot,UTRAN shall derive TPCest to be 0 or 1, and update the powerevery slot;If DPC_MODE = 1, UE repeats the same TPC over 3 slots,UTRAN shall derive TPCest over three slots to be 0 or 1, andupdate the power every three slots.The DPC_MODE parameter is a UE specific parameter and controlled by the UTRAN.The UE shall check the DPC_MODE (Downlink Power Control Mode) beforegenerating the TPC, and upon receiving the TPC, the UTRAN shall adjust its downlinkpower accordingly.317
    • Page55Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power Control ParametersDPCMODEParameter name: Downlink power control modeThe recommended value is SINGLE_TPC, namelyDPC_MODE = 0DPCMODEParameter name: Downlink power control modeValue range: SINGLE_TPC (DPC_MODE=0), TPC_TRIPLET_IN_SOFT(DPC_MODE=1), TPC_AUTO_ADJUSTContent:SIGNLE_TPC, a fast power control mode, indicates that a unique TPCcommand is sent in each time slot on DPCCH.TPC_TRIPLET_IN_SOFT, a slow power control mode, indicates that the sameTPC is sent in three time slots, it is applicable to soft handover and it candecrease the power deviation.TPC_AUTO_ADJUST, an automatically adjusted mode, indicates that the valueof DPC_MODE can be modified by sending the message “ACTIVE SETUPDATE” to UE.Recommended value: SINGLE_TPCSet this parameter through SET FRC, query it through LST FRC, and modify itthrough SET FRC318
    • Page56Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power ControlAfter estimating the TPC, the UTRAN shall set the downlink powerto P(k) for k:th slot according to the following formula:WhereP(k-1) is downlink transmission power in (k-1):th slotPTPC(k) is the adjustment of downlink power in k:th slotPbal (k) is correction value according to the downlink power balanceprocedure. For a single radio link, Pbal (k) equals 0.)k(P)k(P)1k(P)k(P balTPC ++−=If DOWNLINK_POWER_BALANCE_SWITCH is OFF, then Pbal(k) equals 0.319
    • Page57Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power ControlPTPC(k) is calculated according to the following:If the value of “Limited Power Increase Used” parameter is “NotUsed” , then:WhereTPCest (k) is uplink received TPC of the k:th slotΔTPC is downlink power adjustment step size⎩⎨⎧=−=+=0)k(TPCif1)k(TPCif)k(PestTPCestTPCTPCΔΔ320
    • Page58Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power ControlIf the value of “Limited Power Increase Used” parameter is“Used” , then:Where ∑−−==1kSize_Window_Average_Power_DLkiTPCsum )i(P)k(Δ⎪⎩⎪⎨⎧=−≥+=<+=+=0)k(TPCifLimit_Raise_Power)k(and1)k(TPCif0Limit_Raise_Power)k(and1)k(TPCif)k(PestTPCTPCsumestTPCsumestTPCTPCΔΔΔΔΔΔWhere,Power_Raise_Limit : the restriction value of power increasing within a periodDL_Power_Average_Window_Size : the period of DL transmit power increasing.From the definition above, Δsum(k) indicates the sum of downlink power adjustment inthe latest DL_Power_Average_Window_Size time slots.321
    • Page59Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power Control ParametersINNER_LOOP_DL_LMTED_PWR_INC_SWITCHThis is one switch in PCSWITCH (Power control algorithmswitch) parameter.The default value is 0, namely OFF.POWERRAISELIMITParameter name: Power increase limitThe recommended value is 10dBINNER_LOOP_DL_LMTED_PWR_INC_SWITCHThis is one switch in PcSwitch (Power control algorithm switch) parameter.Value range:1 (ON) , 0 (OFF)Content: When it is checked, limited power increase algorithm is applied in theinner loop power control. limited power increase algorithm means that when theDL transmit power is increased, there is a limit for the step, that is, each increaseis limited.Recommended value (default value): 0Set this parameter through SET CORRMALGOSWITCH, query it through LSTCORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCHPOWERRAISELIMITParameter name: Power increase limitValue range: 0 to 10 dBContent: The increase of DL transmit power withinDL_Power_Average_Window_Size cannot exceed this parameter value.Recommended value: 10Set this parameter through ADD CELLSETUP, query it through LST CELL, andmodify it through MOD CELLSETUP322
    • Page60Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Inner Loop Power Control ParametersDLPOWERAVERAGEWINDOWSIZEParameter name: DL power average window sizeThe recommended value is 20 time slotsFDDTPCDLSTEPSIZEParameter name: FDD DL power control step sizeThe recommended value is STEPSIZE_1DB, namely 1dBDLPOWERAVERAGEWINDOWSIZEParameter name: DL power average window sizeValue range: 1 to 60 time slotsContent: UTRAN calculates the increase of DL transmit power within the period definedvia this parameter to determine whether the increase exceeds “Power Raise Limit”. If so,UTRAN will not increase the power even when it receives the command to raise thepowerRecommended value: 20Set this parameter through ADD CELLSETUP, query it through LST CELL ,and modify itthrough MOD CELLSETUPFDDTPCDLSTEPSIZEParameter name: FDD DL power control step sizeValue range: STEPSIZE_0.5DB, STEPSIZE_1DB, STEPSIZE_1.5DB, STEPSIZE_2DBPhysical value range: 0.5, 1, 1.5, 2 dBContent: The step size of the closed loop power control performed on DL DPCH inFrequency Division Duplex (FDD) mode.Recommended value: STEPSIZE_1DBSet this parameter through SET FRC, query it through LST FRC, and modify it throughSET FRC323
    • Page61Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Power BalancePurposeThe purpose of this procedure is tobalance the DL transmission powers ofmore than one Radio Links.The start and stop of DPBThe power offset of two RLs is greaterthan the DPB start threshold, the DPBprocess is startedThe power offset of two RLs is lessthan the DPB stop threshold, the DPBprocess is stoppedNodeB NodeBMonitor theTx power ofNodeBs andstart the DPBprocessDPB processDuring soft handover, the UL TPC is demodulated in each RLS, then due todemodulation errors, the DL transmit power of the each branch in soft handover willdrift separately, which causes loss to the macro-diversity gain.The DL Power Balance (DPB) algorithm is introduced to reduce the power driftbetween links during the soft handover.324
    • Page62Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Power Balance ParametersDOWNLINK_POWER_BALANCE_SWITCHThis is one switch in PCSWITCH (Power control algorithm switch)parameter.The default value is 0, namely OFF.DPBSTARTTHD / DPBSTOPTHDParameter name: DPB start threshold / DPB stop thresholdThe recommended value:DPB start threshold 8, namely 4dB;DPB stop threshold 4, namely 2dB.DOWNLINK_POWER_BALANCE_SWITCHThis is one switch in PcSwitch (Power control algorithm switch) parameter.Value range:1 (ON) , 0 (OFF)Content: When it is checked, Downlink Power Balance (DPB) algorithm is applied to RNC.Downlink power drift among different RLs, which is caused by TPC bit error or otherreasons, could reduce the gain of soft handover. DPB is mainly used to balance thedownlink power of different RLs for an UE in order to achieve the best gain of softhandover.Recommended value (default value): 0Set this parameter through SET CORRMALGOSWITCH, query it through LSTCORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCHDPBSTARTTHD / DPBSTOPTHDParameter name: DPB start threshold / DPB stop thresholdValue range: 0~255Physical value range: 0~127.5dB; step: 0.5Content: The threshold of start / stop DL power balancing in soft handover. When thedifference of the power values of every two paths is greater / smaller than or equal to thisthreshold in soft handover, the RNC shall start / stop DL power balancing; otherwise,shall not.The recommended value is DPB start threshold 8, namely 4dB; DPB stop threshold 4,namely 2dB;Set this parameter through SET DPB, query it through LST DPB and modify it throughSET DPB325
    • Page63Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Closed Loop Power Control3.1 Closed Loop Power Control Overview3.2 Uplink Inner Loop Power Control3.3 Downlink Inner Loop Power Control3.4 Outer Loop Power Control326
    • Page64Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Outer Loop Power ControlWhy we need outer loop power control?SIRBLERDifferent curvescorrespond todifferent multi-pathenvironmentThe reason of outer loop power controlThe QoS which NAS provides to CN is BLER, not SIRThe relationship between inner loop power control and outer loop power controlSIRtar should be satisfied with the requirement of decoding correctly. Butdifferent multi-path radio environments request different SIRTherefore, the outer loop power control can adjust the SIR to get a stable BLERin the changeable radio environment327
    • Page65Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power ControlNodeB UETransmit TPCMeasure SIR andcompare with SIRtarInner loopSet SIRtarOut loopRNCMeasure BLER of receiveddata and compare with theBLERtarSet BLERtarUplink outer-loop power control is performed in the SRNC. The SRNC measures thereceived BLER and compares it with the BLERtar. If the BLERmea is greater than theBLERtar, the SRNC increases the SIRtar; otherwise, the SRNC decreases the SIRtar.328
    • Page66Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power ControlSIRtar AdjustmentWherei is the i:th transmission channel.n is the n:th adjustment period.⎥⎥⎦⎤⎢⎢⎣⎡××−−+−= FactorStepBLERBLER)1n(BLER)1n(SIRMAX)n(SIR ii,tari,tari,meastartarAccording to the formula above,SIRtar(n) is the target SIR used for the n:th adjustment period.MAX means the maximum value among the total i transmission channels.BLERmeas,i (n) is measured for the i:th transmission channel in the n:thadjustment period.BLERtar,i is the target BLER of the i:th transmission channel.Stepi is the adjustment step of the i:th transmission channel.Factor is the adjustment factor.329
    • Page67Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersOPLC_SWITCHThis is one switch in PCSWITCH (Power control algorithmswitch) parameter.The default value is 1, namely ONINITSIRTARGETParameter name: Initial SIR target valueThe recommended value is shown in following table.OPLC_SWITCHThis is one switch in PCSWITCH (Power control algorithm switch) parameter.Value range:1 (ON) , 0 (OFF)Comments: When it is checked, RNC updates the uplink SIR TARGET of RLson the NodeB side by Iub DCH FP signalsDefault value: 1Set this parameter through SET CORRMALGOSWITCH, query it through LSTCORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCHINITSIRTARGETParameter name: Initial SIR target valueValue range: 0 to 255Physical value range: -8.2 to +17.3 dB, step 0.1Content: Defining the initial SIR target value of outer loop power control.Recommended value: refer to the following table.Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB, and modify it through MODTYPSRBOLPC / MOD TYPRABOLPC330
    • Page68Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersSIRADJUSTPERIODParameter name: OLPC adjustment periodThe recommended value is shown in following table.SIRADJUSTFACTORParameter name: SIR adjustment coefficientThe recommended value is 10, namely 1SIRADJUSTPERIODParameter name: OLPC adjustment period.Value range: 1 to 100Physical value range: 10 to 1000 ms, step 10Comments: Outer loop power control varies with radio environment. A fastchanging radio environment leads to a shorter outer loop power controladjustment period, while a slower changing one makes the period longer.Default value: 40Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB, and modify it through MODTYPSRBOLPC / MOD TYPRABOLPCSIRADJUSTFACTORParameter name: SIR adjustment coefficientValue range: 0 to 10Physical value range: 0.1 to 1 , step: 0.1Content: It is used to adjust the best OLPC step for different cells when theOLPC algorithm is given.Recommended value: 10, namely 1Set this parameter through SET OPLC / ADD CELLOLPC, query it through LSTOPLC, and modify it through SET OPLC / MOD CELLOLPC331
    • Page69Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersBLERQUALITYParameter name: Service DCH_BLER target valueThe recommended value is shown in following table.SIRADJUSTSTEPParameter name: SIR adjustment stepThe recommended value is shown in the following table.SIRADJUSTSTEPParameter name: SIR adjustment stepValue range: 0 to 10000Physical value range: 0 to 10 , step: 0.001dBContent: Step of target SIR adjustment in outer loop power control algorithm.Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB ,and modify it through MODTYPSRBOLPC / MOD TYPRABOLPCBLERQUALITYParameter name: Service DCH_BLER target valueValue range: -63 to 0Physical value range: 5×10-7 to 1Content: This QoS-related parameter is used by CRNC to decide the target SIRvalue that influences access and power control. Use the formula below to get theinteger value of the parameter: 10×Log 10(BLER).Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB, and modify it through MODTYPSRBOLPC / MOD TYPRABOLPC332
    • Page70Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersReferential configurations for typical services:-20-20-20-20-20-20-20-20-27-20-20-20ServiceDCH_BLERtarget value142122107102102102102102122102122102SIR inittarget value4444444425104SIRadjustmentstep222222242224OLPCadjustmentperiodPS I/B384kPS I/B256kPS I/B144kPS I/B128kPS I/B64kPS I/B32kPS I/B16kPS I/B8kCSD64kAMR12.2kSRB13.6kSRB3.4kServiceWhere,CSD: CS domain Data serviceI/B: Interactive and Background.333
    • Page71Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power ControlThe parameters MaxSirStepUp and MaxSirStepDown limit theadjustment range of the SIRtar , and the algorithm is:If ΔSIRtar > 0 and ΔSIRtar > “MaxSirStepUp” ,then SIRtar (n+1) = SIRtar (n) + MaxSirStepUpIf ΔSIRtar < 0 and ABS( ΔSIRtar ) > “MaxSirStepDown” ,then SIRtar (n+1) = SIRtar (n) – MaxSirStepDownThe parameters MaxSirtarget and MinSirtarget limit the range ofthe SIRtar at any time.Where,ΔSIRtar is the adjustment of SIRtar, and ΔSIRtar = SIRtar (n+1) - SIRtar (n)ABS( ΔSIRtar ) means absolute value of ΔSIRtar334
    • Page72Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersMAXSIRSTEPUP / MAXSIRSTEPDNParameter name: Maximum SIR increase / decrease stepThe recommended value is shown in following table.MAXSIRTARGET / MINSIRTARGETParameter name: Maximum / Minimum SIR targetThe recommended value is shown in following table.MAXSIRSTEPUP / MAXSIRSTEPDNParameter name: Maximum SIR increase / decrease stepValue range: 0 to 10000Physical value range: 0 to 10 dB, step: 0.001Content: Maximum allowed SIR increase/ decrease step within an outer looppower control adjustment period.The recommended value is shown in following table.Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB ,and modify it through MODTYPSRBOLPC / MOD TYPRABOLPCMAXSIRTARGET / MINSIRTARGETParameter name: Maximum / Minimum SIR targetValue range: 0 to 255Physical value range: -8.2 to17.3 dB, step: 0.1Content: Define the maximum /minimum SIR target value of outer loop powercontrol algorithm.The recommended value is shown in following table.Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query itthrough LST TYPSRB / LST TYPRAB ,and modify it through MODTYPSRBOLPC / MOD TYPRABOLPC335
    • Page73Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Uplink Outer Loop Power Control ParametersReferential configurations for typical services:4004004004004004004004001000500500400MaximumSIR increasestep200200200200200200200200100200200200MaximumSIR decreasestep626262626262626262626262Minimum SIRtarget172152137132132132132132152132132132MaximumSIR targetPS I/B384kPS I/B256kPS I/B144kPS I/B128kPS I/B64kPS I/B32kPS I/B16kPS I/B8kCSD64kAMR12.2kSRB13.6kSRB3.4kServiceWhere,CSD: CS domain Data serviceI/B: Interactive and Background.336
    • Page74Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.Downlink Outer Loop Power ControlNodeBset SIRtarTransmit TPCMeasure SIR andcompare with SIRtarMeasure BLER ofreceived data andcompare with theBLERtarOuter loopInner loopL1L3UEThe downlink outer loop power control is implemented inside the UE. Therefore, thisalgorithm is specified by UE manufacturer.Generally, the UE L3 measures the received BLER and compares it with the BLERtar. Ifthe BLERmea is greater than the BLERtar, the L3 increases the SIRtar and send it to UEL1; otherwise, the L3 decreases the SIRtar.337
    • Page75Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.SummaryIn this course, we have discussed function, principle andcommon parameters of the following power controlalgorithm:Open loop power controlInner loop power controlOuter loop power control338
    • Thank youwww.huawei.com339
    • www.huawei.comCopyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.WCDMA HandoverPrinciple andRelevant Parameters66
    • Page1Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.ForewordWhy mobile system need handover?The mobility of UELoad BalanceAny others ?Handover is a basic function of a cellular mobile network. The purpose of handover isto ensure that a UE in CELL_DCH state is served continuously when it moves.HCS: hierarchical cell structure67
    • Handover types supported by UMTS68
    • Page3Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.ObjectivesUpon completion of this course, you will be able to:Know the features of each handoverKnow the algorithms of handoverKnow the handover procedureKnow the parameters of handoverHandover types supported by UMTS can be classified as:Intra-frequency handoverInter-frequency handoverInter-RAT handover69
    • Page4Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.The Basic Concepts of HandoverActive SetMonitored SetDetected SetRadio Link (RL)Radio Link Set (RLS)Maximum Ratio CombinationSelective CombinationSoft Handover GainP-CPICHActive set : Cells, which belong to the active set. User information is sent from all these cells.In FDD, the cells in the active set are involved in soft handover. The UE shall only consideractive set cells included in the variable CELL_INFO_LIST for measurement; i.e. active set cellsnot included in the CELL_INFO_LIST shall not be considered in any event evaluation andmeasurement reporting.Monitored set :Cells, which are not included in the active set, but are included in theCELL_INFO_LIST belong to the monitored set.Detected set : Cells detected by the UE, which are neither in the CELL_INFO_LIST nor in theactive set belong to the detected set. Reporting of measurements of the detected set is onlyapplicable to intra-frequency measurements made by UEs in CELL_DCH state.RL: Radio link between NodeB and UE.RLS: Radio link set. The RLs from same NodeB.Combination way: For soft handover, the uplink signals are combined in RNC. The RNC willselect one best signal to process. We call this selective combination. For softer handover, theuplink signals are combined in the RAKE receiver of NodeB. It is maximum ratio combination.Soft handover gain: We have introduced in Coverage Planning.CPICH: Common Pilot Channel. UE measure the signal strength of CPICH for handoverdecision.70
    • Page5Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover2. Inter-Frequency Handover3. Inter-RAT Handover71
    • Page6Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency Handover Overview2. Intra-Frequency Handover Procedure3. Signaling Procedures for Intra-Frequency Handover72
    • Page7Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover OverviewCharacters of Intra-Frequency Handover:The carrier frequencies of the current cell and target cell are the sameIntra-frequency soft handoverIntra-frequency hard handover.Intra-frequency handover consists of two types,Intra-frequency soft handover: more than one radio link are set up for the UE.Intra-frequency hard handover: only one radio link is set up for the UE.Intra-frequency soft handover is more commonly used than intra-frequency hardhandover. Intra-frequency hard handover is used only in some special scenarios, forexample, when there is no Iur interface between two RNCs.73
    • Page8Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover OverviewComparison between soft handover and hard handover:Can be happened in Intra-frequency cells or Inter-frequencycellsOnly happenedbetween Intra-frequency cellsThe frequencies of cellsYesNoInterruption duringhandoverOneSeveralThe number of RLs inactive set after handoverHard HandoverHard HandoverSoft HandoverSoft HandoverItemItemThe maximum number of RL is 3. This value can be changed. But this function needthe UE to support. Normally, the active set supported by UE is fixed 3 and can not bechanged.74
    • Page9Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover OverviewIntra-Frequency Soft Handover :Soft HandoverSofter HandoverIntra-Frequency soft handover is a function in which the UE is connected to severalcells at the same time. Addition or release of radio links are controlled by the ACTIVESET UPDATE procedure.During soft handover, a UE is in the overlapping cell coverage area of two sectorsbelonging to different base stations. The communications between UE and basestation take place concurrently via two air interface channels from each base stationseparately.During softer handover, a UE is in the overlapping cell coverage area of two adjacentsectors of a base station. The communications between UE and base station takeplace concurrently via two air interface channels, one for each sector separately.75
    • Page10Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover OverviewUsing selection combinationUsing maximum-ratio combinationUplinksignalUsing maximum-ratio combinationUsing maximum-ratio combinationDownlinksignalOccupying more Iub bandwidthOccupying less Iub bandwidthResourceuseWhen the UE is in the overlappedcoverage area of two neighboringcells of different NodeBsWhen the UE is in the overlappedcoverage area of two neighboringcells of a NodeB with combined RLsScenarioSoft HandoverSoft HandoverSofter HandoverSofter HandoverItemItemComparison between soft handover and softer handover :During softer handover, the uplink signaling are combined inNodeB by maximum ratio combination, but during softhandover they are combined in RNC by selectivecombinationCompare to later one, the maximum ratio combination canget more gain. So the performance of maximum ratiocombination is betterSince softer handover is completed in NodeB, it do notconsume transport resource of Iub76
    • Page11Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover OverviewIntra-Frequency Hard Handover :No Iur interfaceIur interface is congestedHigh-speed Best Effort (BE) service HandoverSoft handover failsIntra-frequency hard handover refers to a handover where all the old radio links arereleased before the new radio links are established. Compared with soft handover,intra-frequency hard handover uses fewer resources.The scenarios of intra-frequency hard handover are as follows:The UE needs to perform the intra-frequency handover between twocells configured in different RNCs. No Iur interface is present betweenRNCs.The UE needs to perform the intra-frequency handover between twocells configured in different RNCs. The Iur interface is congestedbetween RNCs.There is a high-speed Best Effort (BE) service.Compared with soft handover, intra-frequency hard handover is used tosave downlink bandwidth for a high-speed BE service.The intra-frequency soft handover fails and intra-frequency hardhandover is allowed.When intra-frequency soft handover fails because of a congestion problem of thetarget cell, the RNC tries an intra-frequency hard handover with a lower service bitrate.The INTRA_FREQUENCY_HARD_HANDOVER_SWITCH parameter in the SETCORRMALGOSWITCH command is used to determine whether to enable intra-frequency hard handover. By default, this switch is ON.77
    • Page12Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency Handover Overview2. Intra-Frequency Handover Procedure3. Signaling Procedures for Intra-Frequency Handover78
    • Page13Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover ProcedureDecisionExecutionMeasurementThe following figure shows handoverprocedureDecision phaseExecution phaseMeasurement phaseYesNoAre handover criteria satisfied?Perform a handover and update relative parametersMeasure the CPICH Ec/N0 of the serving cell andits neighboring cells as well as the relative timedifference between the cellsIntra-frequency handover procedure is divided into three phases: handovermeasurement, handover decision, and handover execution.After the UE transits to CELL_DCH state in connected mode during a call, the RNCsends a measurement control message to instruct the UE to take measurements andreport the measurement event results.Upon receiving an event report from the UE, the RNC makes a handover decisionand performs the corresponding handover79
    • Page14Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency Handover Overview2. Intra-Frequency Handover Procedure1. Intra-Frequency Handover Measurement2. Intra-Frequency Handover Decision and Execution3. Neighboring Cell Combination Algorithm3. Signaling Procedures for Intra-Frequency Handover80
    • Page15Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UE UTRANMEASUREMENT CONTROLIntra-Frequency Handover MeasurementMEASUREMENT CONTROLThe measurement control message carries the following information:Event trigger thresholdHysteresis valueEvent trigger delay timeNeighboring cell list81
    • Page16Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UE UTRANMEASUREMENT REPORTMEASUREMENT REPORTIntra-Frequency Handover MeasurementThe purpose of the measurement reporting procedure is to transfermeasurement results from the UE to UTRAN.Based on the algorithm in measurement control, the UE will measure thesignal strength or quality and check if it meet the requirement of all event. If itmeet the requirement of any event, UE will send the measurement report toUTRAN to trigger the handover. The most important information in themeasurement are the PSC , the CPICH Ec/No of the target cell, and thetriggered event.82
    • Page17Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover MeasurementL3 Filtering for Intra-Frequency HandoverThe value after L3 filtering procedure is calculated according to following formula:Fn = (1 - α) x Fn-1 + α x MnwhereFn is the new measurement value obtained after L3 filtering.Fn-1 is the last measurement value obtained after L3 filtering.Mn is the latest measurement value obtained from the physical layer.α = 1/2(k/2) (k is set to Intra-freq meas L3 filter coeff)When α is set to 1, that is, k = 0, no L3 filtering is performed.A is measurement value at the physical layerB is the measurement value after layer 1 filtering at physical layer. The value goes from thephysical layer to high layerC is measurement after processing in the layer3 filterC’ is another measurement valueD is measurement report information sent on the radio interface or Iub interface83
    • Page18Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Key parameters of Intra-frequency MeasurementIntra-freq Measure QuantityParameter ID: IntraFreqMeasQuantityThe default value of this parameter is CPICH_Ec/NoIntra-freq meas L3 filter coeffParameter ID: FilterCoefThe default value of this parameter is 3The measurement quantity of intra-frequency handover can be Common PilotChannel (CPICH) Ec/No or CPICH Received Signal Code Power (RSCP). It canbe used in all the measurement events of intra-frequency handoverIntra-freq Measure QuantityParameter ID: IntraFreqMeasQuantityValue range: CPICH_Ec/No, CPICH_RSCPContent: This parameter specifies the measurement quantity used in intra-frequency measurement.The default value of this parameter is CPICH_Ec/NoSet this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .Before judging a measurement event and sending the measurement report, theUE performs L3 filtering for the measurement value.Intra-freq meas L3 filter coeffParameter ID: FilterCoefValue range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19Content: This parameter specifies the intra-frequency measurement L3 filtercoefficient. The greater this value is set, the greater the smoothing effect andthe higher the anti-fast fading capability are, but the lower the signal changetracing capability is.The default value of this parameter is 3Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .84
    • A non-active PCPICH becomes better than an active PCPICH. Thisindicates that the quality or strength of a cell is close to the best cell.In addition ,the number of cells in the active set has reached themaximum value. The cell replaces the worst cell in the active set ;thus achieving a higher combined gain1CRAN10.0 provides the solution to the issue of how to add anHSUPA cell in a DCH active set to an E-DCH active set. Event 1Jis added to the 3GPP protocol. This event is triggered when a non-active E-DCH but active DCH primary CPICH becomes better thanan active E-DCH primary CPICH.1JEvent of the change of the best cell1DThe PCPICH quality or strength of the cells in the active set leavesthe reporting range. This indicates that a cell is much worse thanthe quality of the best cell. The cell should not stay in the active set1BThe PCPICH quality or strength of the cells in the monitored setenters the reporting range . This indicates that the cell is close tothe best cell . A relative high combined gain can be achieved whenthe cell is added to the active set1ADescriptionEventIntra-Frequency Handover Measurement Events85
    • Page20Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1A is triggered on the basis of the following formula1A EVENTIntra-Frequency Handover Measurement)2/()1( 111aaBestNiiNewNew HRMWMWCIOMA−−−+⎟⎟⎠⎞⎜⎜⎝⎛≥+ ∑=MNew is the measurement value of the cell in the reporting range.CIONew is equal to the sum of Cell oriented Cell Individual Offset andNeighboring cell oriented CIO, which is the offset between the cell in thereporting range and the best cell in the active set.W represents Weighted factor, used to weight the quality of the active set.Mi is the measurement value of a cell in the active set.NA is the number of cells not forbidden to affect the reporting range in theactive set.MBest is the measurement value of the best cell in the active set.R1a is the reporting range or the relative threshold of soft handover. Thethreshold parameters of the CS non-VP service, VP service, and PS serviceare as follows:CS non VP service 1A event relative THDVP service 1A event relative THDPS service 1A event relative thresholdH1a represents 1A hysteresis, the hysteresis value of event 1A.86
    • Page21Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.A: signal curve of the best cell in the active setB: signal curve of a cell in the monitoring setC: Th1A curve1A EVENTIntra-Frequency Handover MeasurementIf the signal quality of a cell that is not in the active set is higher than Th1A for a period of timespecified by 1A event trigger delay time (that is, Time to trigger in the figure), the UE reportsevent 1A87
    • Page22Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Intra-Frequency HandoverCS non VP service 1A event relative THDParameter ID: IntraRelThdFor1ACSNVPThe default value of this parameter is 6 ( 3dB )VP service 1A event relative THDParameter ID: IntraRelThdFor1ACSVPThe default value of this parameter is 6 ( 3dB )PS service 1A event relative thresholdParameter ID: IntraRelThdFor1APSThe default value of this parameter is 6 ( 3dB )CS non VP service 1A event relative THDParameter ID: IntraRelThdFor1ACSNVPValue range: 0~14.5; step: 0.5Content: This parameter specifies the relative threshold of event 1A for the CS non-VPservice. The larger the parameter value is, the more easily event 1A is triggered..The default value of this parameter is 6 (3dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .VP service 1A event relative THDParameter ID: IntraRelThdFor1ACSVPValue range: 0~14.5; step: 0.5Content: This parameter specifies the relative threshold of event 1A for the VP service.The larger the parameter value is, the more easily event 1A is triggered..The default value of this parameter is 6 (3dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .PS service 1A event relative THDParameter ID: IntraRelThdFor1APSValue range: 0~14.5; step: 0.5Content: This parameter specifies the PS service relative threshold of event 1A. Thesmaller the parameter value is, the more easily event 1A is triggered.The default value of this parameter is 6 (3dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .88
    • Page23Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Cell oriented Cell Individual OffsetParameter ID: CIOThe default value of this parameter is 0 (0dB )Neighboring cell oriented CIOParameter ID: CIOOffsetThe default value of this parameter is 0 (0dB )Parameters of Intra-Frequency HandoverCell oriented Cell Individual OffsetParameter ID: CIOValue range: -10 to +10Content: This parameter is used together with Neighboring celloriented CIO. The sum of the two parameter values is added to themeasurement quantity before the UE evaluates whether an eventoccurred. In handover algorithms, this parameter is used for movingthe border of a cell.The default value of this parameter is 0 ( 0dB )Set this parameter through ADD CELLSETUP/MOD CELLSETUPNeighboring cell oriented CIOParameter ID: CIOOffsetValue range: -10 to +10Content: This parameter is used together with Cell oriented Cell IndividualOffset. The sum of the two parameter values is added to the measurementquantity before the UE evaluates whether an event has occurred. In handoveralgorithms, this parameter is used for moving the border of 2 neighbors.The default value of this parameter is 0 ( 0dB )Set this parameter through ADD INTRAFREQNCELL/MOD INTRAFREQNCELL89
    • Page24Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1A hysteresisParameter ID: Hystfor1AThe default value of this parameter is 0 (0dB )1A event trigger delay timeParameter ID: TrigTime1AThe default value of this parameter is D320 ( 320ms )Weighted factorParameter ID: WeightThe default value of this parameter is 0Parameters of Intra-Frequency Handover1A hysteresisParameter ID: Hystfor1AValue range: 0~7.5; step: 0.5Content: This parameter specifies the hysteresis value of event 1A. It is related to theslow fading characteristic.The default value of this parameter is 0 (0dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .1A event trigger delay timeParameter ID: TrigTime1AValue range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000msContent: This parameter specifies the trigger delay time of event 1A. It is related to theslow fading characteristic. The greater the parameter value, the smaller the probability ofmisjudgment, but the slower the response of event reporting, triggered by measured signalchanges.The recommended value of this parameter is D320 ( 320ms )Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .Weighted factorParameter ID: WeightValue range: 0~20,step:0.1Content: This parameter is used to define the soft handover relative threshold based onthe measured value of each cell in the active set. The greater the parameter value, thehigher the soft handover relative threshold. When this value is set to 0, the soft handoverrelative threshold is determined only by the best cell in the active set. .The Default Value of this parameter is 0Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO . 90
    • Page25Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover MeasurementEvent Trigger ReportEvent to Periodical Report1A Event Report Mode:The report mode of 1A is Event Trigger Report .Generally the event 1A is reported only once. However, to avoid measurement reportloss, the event 1A reporting can be turned to periodical reporting.91
    • Page26Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1A event to periodical rpt periodParameter ID: ReportIntervalfor1AThe default value of this parameter is D4000 (4000 ms )1A event to periodical rpt numberParameter ID: PeriodMRReportNumfor1AThe default value of this parameter is D16Parameters of Intra-Frequency Handover1A event to periodical rpt periodParameter ID: ReportIntervalfor1AValue range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000,D4000, D8000, D16000Content: The reporting period for the event 1A. Generally the event 1A isreported only once. However, to avoid measurement report loss, the event 1Areporting can be turned to periodical reporting.The default value of this parameter is D4000 (4000 ms)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1A event to periodical rpt numberParameter ID: PeriodMRReportNumfor1AValue range: D1, D2, D4, D8, D16, D32, D64, infinityContent: The periodical reporting times for the event 1A. When the actualtimes exceed this parameter, the periodical reporting comes to an end.The recommended value of this parameter is D16Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .92
    • Page27Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1B is triggered on the basis of the following formula1B EVENT),2/()1( 111bbBestNiiOldOld HRMWMWCIOMA+−−+⎟⎟⎠⎞⎜⎜⎝⎛≤+ ∑=Intra-Frequency Handover MeasurementMOld is the measurement value of the cell that becomes worse.CIOOld is equal to the sum of Cell oriented Cell Individual Offset andNeighboring cell oriented CIO, which is the offset between the cell in thereporting range and the best cell in the active set.W represents Weighted factor, used to weight the quality of the active set.Mi is the measurement value of the cell in the active set.NA is the number of cells not forbidden to affect the reporting range in theactive set. MBest is the measurement value of the best cell in the active set.R1b is the reporting range or the relative threshold of soft handover. Thethreshold parameters of the CS non-VP service, VP service, and PS servicesare as follows:CS non VP service 1B event relative THDVP service 1B event relative THDPS service 1B event relative thresholdH1b represents 1B hysteresis, the hysteresis value of event 1B.93
    • Page28Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1B EVENTA: signal curve of the best cell in the active setB: signal curve of a cell in the monitoring setC: Th1B curveIntra-Frequency Handover MeasurementIf the signal quality of a cell in the active set is lower than Th1B curve for a period oftime specified by 1B event trigger delay time (Time to trigger in the figure), the UEreports event 1B94
    • Page29Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Intra-Frequency HandoverCS non VP service 1B event relative THDParameter ID: IntraRelThdFor1BCSNVPThe default value of this parameter is 12 ( 6dB )VP service 1B event relative THDParameter ID: IntraRelThdFor1BCSVPThe default value of this parameter is 12 ( 6dB )PS service 1B event relative thresholdParameter ID: IntraRelThdFor1BPSThe default value of this parameter is 12 ( 6dB )CS non VP service 1B event relative THDParameter ID: IntraRelThdFor1BCSNVPValue range: 0~14.5; step: 0.5Content: This parameter specifies the relative threshold of event 1B for the CS non-VP service. The smaller the parameter value is, the more easily event 1B is triggered .The default value of this parameter is 12 (6dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .VP service 1B event relative THDParameter ID: IntraRelThdFor1BCSVPValue range: 0~14.5; step: 0.5Content: This parameter specifies the relative threshold of event 1A for the VPservice. The smaller the parameter value is, the more easily event 1B is triggered .The default value of this parameter is 12 (6dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .PS service 1A event relative THDParameter ID: IntraRelThdFor1APSValue range: 0~14.5; step: 0.5Content: This parameter specifies the PS service relative threshold of event 1A. Thesmaller the parameter value is, the more easily event 1B is triggered .The default value of this parameter is 12 (6dB)Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO .95
    • Page30Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1B hysteresisParameter ID: Hystfor1BThe default value of this parameter is 0 (0dB )1B event trigger delay timeParameter ID: TrigTime1BThe default value of this parameter is D640 ( 640ms )Parameters of Intra-Frequency Handover1B hysteresisParameter ID: Hystfor1BValue range: 0~7.5; step: 0.5Content: This parameter specifies the hysteresis value of event 1B. It is relatedto the slow fading characteristic.The default value of this parameter is 0 (0dB)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1B event trigger delay timeParameter ID: TrigTime1BValue range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560,5000 msContent: This parameter specifies the trigger delay time of event 1B. It isrelated to the slow fading characteristic. The greater the parameter value, thesmaller the probability of misjudgment, but the slower the response of eventreporting, triggered by measured signal changes.The recommended value of this parameter is D640 ( 640ms )Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .96
    • Page31Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1C is triggered on the basis of the following formula1C EVENT,2/1cInASInASNewNew HCIOMCIOM ++≥+Intra-Frequency Handover MeasurementMNew is the measurement value of the cell in the reporting range.CIONew is the cell individual offset value of the cell in the reporting range. It isequal to the sum of Cell oriented Cell Individual Offset and Neighboringcell oriented CIO, which is the offset between the cell in the reporting rangeand the best cell in the active set.MInAS is the measurement value of the worst cell in the active set.CIOInAS is the cell individual offset value of the worst cell in the active set. It isequal to the sum of Cell oriented Cell Individual Offset and Neighboringcell oriented CIO.H1c represents 1C hysteresis, the hysteresis value of event 1C.97
    • Page32Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.A: signal curve of the best cell in the active setB: signal curve of a cell in the active setC: signal curve of the worst cell in the active setD: signal curve of a cell in the monitoring setE: Th1C curve1C EVENTIntra-Frequency Handover MeasurementIf the signal quality of a cell not in the active set is higher than Th1C for a period of timespecified by 1C event trigger delay time (Time to trigger in the figure), the UEreports event 1C98
    • Page33Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1C hysteresisParameter ID: Hystfor1CThe default value of this parameter is 8 (4dB )1C event trigger delay timeParameter ID: TrigTime1CThe default value of this parameter is D640 ( 640ms )Parameters of Intra-Frequency Handover1C hysteresisParameter ID: Hystfor1CValue range: 0~7.5; step: 0.5Content: This parameter specifies the hysteresis value of event1C. It is related to the slow fading characteristic.The default value of this parameter is 8 (4dB)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1C event trigger delay timeParameter ID: TrigTime1CValue range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320,640, 1280, 2560, 5000 msContent: This parameter specifies the trigger delay time ofevent 1C. It is related to the slow fading characteristic. Thegreater the parameter value, the smaller the probability ofmisjudgment, but the slower the response of event reporting,triggered by measured signal changes.The recommended value of this parameter is D640 ( 640ms )Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .99
    • Page34Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover MeasurementEvent Trigger ReportEvent to Periodical Report1C Event Report Mode:The report mode of 1C is Event Trigger Report .Generally the event 1C is reported only once. However, to avoid measurement reportloss, the event 1C reporting can be turned to periodical reporting.100
    • Page35Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1C event to periodical rpt periodParameter ID: ReportIntervalfor1CThe default value of this parameter is D4000 (4000 ms )1C event to periodical rpt numberParameter ID: PeriodMRReportNumfor1CThe default value of this parameter is D16Parameters of Intra-Frequency Handover1C event to periodical rpt periodParameter ID: ReportIntervalfor1CValue range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000,D4000, D8000, D16000Content: The reporting period for the event 1C. Generally the event 1C isreported only once. However, to avoid measurement report loss, the event 1Creporting can be turned to periodical reporting.The default value of this parameter is D4000 (4000 ms)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1C event to periodical rpt numberParameter ID: PeriodMRReportNumfor1CValue range: D1, D2, D4, D8, D16, D32, D64, infinityContent: The periodical reporting times for the event 1C. When the actualtimes exceed this parameter, the periodical reporting comes to an end.The recommended value of this parameter is D16Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .101
    • Page36Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1D is triggered on the basis of the following formula1D EVENT,2/10 1dBestNotbest HMM +≥Intra-Frequency Handover MeasurementMNotBest is the measurement value of a cell that is not in the list of thebest cells.MBest is the measurement value of the best cell in the active set.H1d represents 1D hysteresis, the hysteresis value of event 1D.102
    • Page37Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1D EventA: signal curve of the best cell in the active setB: signal curve of a cell in the active set or monitoring setC: Th1D curveIntra-Frequency Handover MeasurementIf the signal quality of a cell not in the active set is higher than Th1D for aperiod of time specified by 1D event trigger delay time (Time to trigger in thefigure), the UE reports event 1D103
    • Page38Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1D hysteresisParameter ID: Hystfor1DThe default value of this parameter is 8 (4dB )1D event trigger delay timeParameter ID: TrigTime1DThe default value of this parameter is D640 ( 640ms )Parameters of Intra-Frequency Handover1D hysteresisParameter ID: Hystfor1DValue range: 0~7.5; step: 0.5Content: This parameter specifies the hysteresis value of event1D. It is related to the slow fading characteristic.The default value of this parameter is 8 (4dB)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1D event trigger delay timeParameter ID: TrigTime1DValue range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320,640, 1280, 2560, 5000 msContent: This parameter specifies the trigger delay time ofevent 1D. It is related to the slow fading characteristic. Thegreater the parameter value, the smaller the probability ofmisjudgment, but the slower the response of event reporting,triggered by measured signal changes.The recommended value of this parameter is D640 ( 640ms )Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .104
    • Page39Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1J is triggered on the basis of the following formula1J EVENTIntra-Frequency Handover Measurement,2/1JInASInASNewNew HCIOMCIOM ++≥+Reporting event 1J: A non-active E-DCH but active DCH primary CPICH becomes better thanan active E-DCH primary CPICHMNew is the measurement result of the cell not included in the E-DCH active set but included inDCH active set.CIONew is the individual cell offset for the cell not included in the E-DCH active set but includedin DCH active set becoming better than the cell in the E-DCH active set if an individual celloffset is stored for that cell. Otherwise, it equals 0.MInAS is the measurement result of the cell in the E-DCH active set with the lowestmeasurement result.CIOInAS is the individual cell offset for the cell in the E-DCH active set that is becoming worsethan the new cell.H1J is the hysteresis parameter for event 1J.105
    • Page40Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1J EventIntra-Frequency Handover MeasurementA: signal quality curve of a cell in the E-DCH active setB: signal quality curve of the worst cell in the E-DCH active setC: signal quality curve of a cell not in the E-DCH active set but included in DCH active setD: signal quality curve of a cell not in the E-DCH active set but included in DCH active setIn the figure, the hysteresis and the cell individual offsets for all cells equal 0The first measurement report is sent when primary CPICH D becomes better than primaryCPICH B. The "cell measurement event result" of the measurement report contains theinformation of primary CPICH D and CPICH B.On the assumption that the E-DCH active set has been updated after the first measurementreport (E-DCH active set is now primary CPICH A and primary CPICH D), the second report issent when primary CPICH C becomes better than primary CPICH A. The "cell measurementevent result" of the second measurement report contains the information of primary CPICH Cand primary CPICH A.The parameters described in the following need to be set on the RNC LMT:1J hysteresis1J event trigger delay time1J event to periodical rpt number1J event to periodical rpt period106
    • Page41Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Intra-Frequency Handover1J Event function3GPP define the maximum DCH active set size is 6 and the maximumE-DCH active set size is 4The DCH active set covers the E-DCH active set or they are the sameThe best cell in E-DCH active set should be the same as that in DCHactive setUplink channel type of UE is decided by the best cell in DCH activesetUplink channel is E-DCH if the best cell in DCH active set supports HSUPAUplink channel is DCH if the best cell in DCH active set can NOT supportHSUPA107
    • Page42Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Intra-Frequency HandoverProcessing procedure for 1J EventThe UE reports 1J Event if it find a non-active E-DCH but active DCHcell PCICH becomes better than an active E-DCH PCIPCHRNC will add the target cell into E-DCH active set if the E-DCH active set isNOT fullRNC will perform replace procedure if the E-DCH active set is full108
    • Page43Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1J hysteresisParameter ID: Hystfor1JThe default value of this parameter is 8 (4dB )1J event trigger delay timeParameter ID: TrigTime1JThe default value of this parameter is D640 ( 640ms )Max number of cell in edch active cellParameter ID: MAXEDCHCELLINACTIVESETThe default value of this parameter is 3Parameters of Intra-Frequency Handover1J hysteresisParameter ID: Hystfor1JValue range: 0~7.5; step: 0.5Content: This parameter specifies the hysteresis value of event 1J. Itis related to the slow fading characteristic.The default value of this parameter is 8 (4dB)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .1J event trigger delay timeParameter ID: TrigTime1JValue range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640,1280, 2560, 5000 msContent: This parameter specifies the trigger delay time of event 1D.It is related to the slow fading characteristic.The recommended value of this parameter is D640 ( 640ms )Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .Max number of cell in edch active cellParameter ID: MAXEDCHCELLINACTIVESETValue range: 1 to 4Content: This parameter specifies the maximum number of cells inthe E-DCH active set.The recommended value of this parameter is 3Set this parameter through SET HOCOMM .109
    • Page44Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.1A Event Report Mode:Event Trigger ReportEvent to Periodical ReportParameters1J event to periodical rpt periodParameter ID: ReportIntervalfor1JThe default value of this parameter is D1000 (1000 ms )1J event to periodical rpt numberParameter ID: PeriodMRReportNumfor1JThe default value of this parameter is D64Parameters of Intra-Frequency HandoverThe report mode of 1J is Event Trigger Report .Generally the event 1J is reported only once. However, to avoid measurementreport loss, the event 1J reporting can be turned to periodical reporting.1J event to periodical rpt periodSet this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO1J event to periodical rpt numberSet this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO110
    • Page45Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency Handover Overview2. Intra-Frequency Handover Procedure1. Intra-Frequency Handover Measurement2. Intra-Frequency Handover Decision and Execution3. Neighboring Cell Combination Algorithm3. Signaling Procedures for Intra-Frequency Handover111
    • Page46Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Handover Decision and ExecutionRNC will make decision and execute handover depends on theEvents the RNC receives.1A Event1B Event1C Event1D Event1J EventWhen receiving an event 1C report, the RNC decides whether to changethe worst cell.For event 1C, the UE reports a list that contains good cells and the cellsto be replaced, and sequences the cells in descending order bymeasurement quantity.After receiving the list from the UE, the RNC replaces the bad cells in theactive set with the good cells in the list.1CWhen receiving an event 1B report, the RNC determines whether todelete a cell.1BWhen receiving an event 1A report, the RNC decides whether to add acell.For event 1A, the UE can report more than one cell in the event list inone measurement report. These cells are in the list of the MeasurementControl message, and they are sequenced in descending order bymeasurement quantity.For the cells in the list, the RNC adds the radio link to the active set onlyif the number of cells in the active set does not reach the maximum value.1ADecision and ExecutionEvent112
    • When receiving an event 1J report with information about the good cellsand the cells to be replaced, the RNC proceeds as follows:•If the current number of cells in the E-DCH active set is less than the valueof Max number of cell in edch active set, the uplink of the cell whereevent 1J is triggered is reconfigured to E-DCH.•If the current number of cells in the E-DCH active set is equal to the valueof Max number of cell in edch active set, the RNC searches themeasurement report for the non-serving Cell_EDCH with the lowestmeasured quality in the E-DCH active set. Then, the uplink of the cellwhere event 1J is triggered is reconfigured from DCH to E-DCH, andthe uplink of CELL-EDCH is reconfigured from E-DCH to DCH.1JWhen receiving an event 1D report, which includes information about onlyone cell, the RNC learns that the quality of this cell is better than that of theserving cell and takes one of the following actions:•If the reported cell is in the active set, the RNC decides whether to changethe best cell or reconfigure measurement control.•If the reported cell is in the monitored set,•If the number of cells in the active set has not reached themaximum value, the RNC decides a soft handover and adds thecell to the active set.•If the number of cells in the active set has reached the maximumvalue, the RNC decides a soft handover and replaces the worst cellin the active set with the reported cell.•The RNC determines whether the intra-frequency hard handover scenariosare applicable. For detailed information, see 3.1 Intra-Frequency HandoverTypes. If any scenario is applicable, the RNC performs an intra-frequencyhard handover.1D113
    • Page48Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Max number of cell in active setParameter ID: MaxCellInActiveSetThe default value of this parameter is 3Minimum Quality Threshold for SHOParameter ID: SHOQualminThe default value of this parameter is -24 ( -24dB)Parameters of Intra-Frequency HandoverWhen make decision, RNC must follow these restrictionsMax number of cell in active setParameter ID: MaxCellInActiveSetValue range: 1~6;Content: This parameter specifies the Max number of cell inactive set.The default value of this parameter is 3Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .Minimum Quality Threshold for SHOParameter ID: SHOQualminValue range: -24~0,step:1dBContent: This parameter specifies the minimum qualitythreshold for soft handover..The recommended value of this parameter is -24 (-24dB)Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO .114
    • Page49Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.For R99 NRT services to increase the probability of a successful softhandover, the rate reduction is triggered after a admission failureRate Reduction After an SHO Failure1A,1C,1D is received by RNCExecute admission control in target cellAdmission succeed?Execute HandoverRate ReductionIf the RNC receives a 1A, 1C, or 1D measurement report, thecorresponding cell tries to admit the UE. If the cell fails to admitthe UE, the RNC performs the estimation procedure for ratereduction.115
    • Page50Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.procedure for rate reductionEstimationExecutionRate Reduction After an SHO Failure116
    • Estimation Procedure for Rate Reduction117
    • The estimation procedure after the cell fails to admit the UE is described as follows:Step 1 : The RNC evaluates whether the measurement quantity of the cell failingto be admitted meets the condition of rate reduction.If the condition is met, the RNC performs a rate reduction process for thehandover service immediately.If the condition is not met, the RNC performs Step2.The condition of rate reduction is as follows:Mnew > Mbest_cell - RelThdForDwnGrdwhereMnew is the CPICH Ec/No measurement value of the cell failing to be admitted.Mbest_cell is the CPICH Ec/No measurement value of the best cell in the activeset.RelThdForDwnGrd is configured through the parameter Relative threshold ofSHO failure.Step 2 :The RNC evaluates whether the number of SHO failures in the cellexceeds the Threshold number of SHO failure.If the number of SHO failures in the cell is smaller than the Threshold numberof SHO failure, the RNC determines whether the SHO failure evaluation timerhas been started:If the timer has not been started, the RNC starts it.If the timer has been started, the RNC increments the SHO failurecounter by one.Before the SHO failure evaluation timer expires, no action is takenand the RNC waits for the next measurement report period.When the SHO failure evaluation timer expires, the RNC sets the SHO failurecounter of the corresponding cell to 0 and ends the evaluation.If the number of SHO failures in the cell is larger than or equal to theThreshold number of SHO failure, the RNC performs a rate reductionprocess for the access service and sets the SHO failure counter of thecorresponding cell to 0.118
    • Page53Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Relative threshold of SHO failureParameter ID: RelThdForDwnGrdThe default value of this parameter is 2 ( 1dB )Max evaluation period of SHO failureParameter ID: ShoFailPeriodThe default value of this parameter is 60 ( 60s )Threshold number of SHO failureParameter ID: ShoFailNumForDwnGrdThe default value of this parameter is 3Parameters of Intra-Frequency HandoverRelative threshold of SHO failureParameter ID: RelThdForDwnGrdValue range: -29 to +29 ; step: 0.5 dBContent: This parameter specifies the relative threshold for direct rate reduction after an SHOfailure. If the difference between the signal quality of the target cell to which an SHO fails and thatof the best cell is lower than this relative threshold, the RNC directly initiates a rate reductionprocess in the active set, regardless of the limitation on the number of SHO failures.The default value of this parameter is 2 (1dB)Set this parameter through SET INTRAFREQHO.Max evaluation period of SHO failureParameter ID: ShoFailPeriodValue range: 0~120sContent: This parameter specifies the maximum evaluation period of SHO failures for ratereduction. During the evaluation period, the RNC records the number of SHO failures in at mostthree cells for each UE. After the evaluation period, the RNC clears this record.The recommended value of this parameter is 60 ( 60s )Set this parameter through SET INTRAFREQHOThreshold number of SHO failureParameter ID: ShoFailNumForDwnGrdValue range: 0~63Content: This parameter specifies the threshold number of SHO failures for rate reduction. If thenumber of SHO failures in a cell reaches or exceeds this threshold during the period specified byMax evaluation period of SHO failure, the RNC performs a rate reduction process in the activeset. After the rate reduction succeeds, the RNC initiates an SHO in the cell.The recommended value of this parameter is 3Set this parameter through SET INTRAFREQHO119
    • The rate reduction execution procedure is :Step1:The RNC performs a rate reduction process for theaccess service.Step2:After the rate reduction succeeds, the RNC immediatelyattempts to add this cell to the active set without measurement:If the cell succeeds in admitting the UE, theRNC adds the radio link and sets the SHOfailure counter of the cell to 0 and ends theexecution.If the cell fails to admit the UE, the RNC startsthe Period of penalty timer for SHO failureafter down rate to avoid an increase in the ratetriggered by DCCC within the period. Also in thisperiod, the RNC sets the SHO failure counter ofthe cell to 0 and ends the execution.If fails to perform a soft handover again, RNC performs theestimation procedure and the execution procedure, aspreviously described.Execution Procedure of Rate Reduction120
    • Page55Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Period of penalty timer for SHO failure after down rateParameter ID: DcccShoPenaltyTimeThe default value of this parameter is 30 ( 30s )Parameters of Rate Reduction ExecutionPeriod of penalty timer for SHO failure after down rateParameter ID: DcccShoPenaltyTimeValue range: 0 to 255 ; step: 1 sContent: If an SHO fails again after the rate reduction, the RNC is forbidden to increase the rateduring the period specified by this parameter.The default value of this parameter is 30 ( 30s)Set this parameter through SET INTRAFREQHO.121
    • Page56Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency handover Overview2. Intra-Frequency Handover Procedure1. Intra-Frequency Handover Measurement2. Intra-Frequency Handover Decision and Execution3. Neighboring Cell Combination Algorithm3. Signaling Procedures for Intra-Frequency Handover122
    • Page57Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Neighboring Cell Combination AlgorithmWhen the UE is in soft handover stateIntra-frequency neighboring cellsInter-frequency neighboring cellsInter-RAT neighboring cellsThe combined neighboring cell list is affect by :Repeat timesServing cell signal quality (Ec/No) orderNeighboring cell priorityAfter obtaining the intra-frequency neighboring cells of each cell in the active set, the RNC calculatesthe union neighboring cell set of the intra-frequency cells, which is also referred as Sall, by using thefollowing method. This method can also be used to generate the Sall of inter-frequency or inter-RATcells.1,The intra-frequency, inter-frequency and inter-RAT neighboring cells of each cell in the currentactive set are obtained.2,The RNC sequences the cells in the active set in descending order of CPICH Ec/No according tothe latest measurement report (event 1A, 1B, 1C, or 1D) from the UE. The best cell is based onevent 1D, whereas other cells are based on the latest measurement report.3,The cells in the active set are added to Sall.4,The neighboring cells of the best cell in the active set are added to Sall. The priority of neighborcell, which are set for each neighboring cell, are used to change the order of adding theneighboring cells to Sall.5,The neighboring cells of other cells in the active set are added to Sall in descending order byCPICH Ec/No values of these cells in the active set. The neighboring cells of the same cell inthe active set are added according to The priority of neighbor cell and repeated number ofrepeated neighboring cell is recorded.6,If there are more than 32 neighboring cells in Sall, delete the neighboring cells whose repeatnumber in Sall is less. The top 32 neighboring cells are grouped into the final Sall.If The flag of the priority is switched to FALSE, The priority of neighbor cell is cleared.If The flag of the priority is switched to TRUE, The priority of neighbor cell is setsimultaneously.123
    • Page58Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of Neighboring Cell Combination AlgorithmNeighboring Cell Combination SwitchParameter ID: NCELL_COMBINE_SWITCHThe default value of this parameter is OFFThe flag of the priorityParameter ID: NPrioFlagThe default value of this parameter is FALSEThe priority of neighbor cellParameter ID: NPrioThe default value of this parameter is NoneThe NCELL_COMBINE_SWITCH of Handover Algorithm Switch parameterdecides the measurement range of neighboring cellsIf the switch is set to ON, measurement objects are chosen from theneighboring cells of all the cells in the active set.If the switch is set to OFF, measurement objects are chosen from theneighboring cells of the best cell.But, limited by the 3GPP, the maximum number of neighboring cells is 32. So ifthe NCELL_COMBINE_SWITCH is ON, it very possible that the neighboringcell of all the cells in the active set may exceed 32.By the Neighboring Cell Combination Algorithm , RNC will choose 32 neighboringcell for measurement.Neighboring Cell Combination SwitchParameter ID: NCELL_COMBINE_SWITCHValue range: OFF, ONContent: If the switch is set to ON, measurement objects are chosen from theneighboring cells of all the cells in the active set.If the switch is set to OFF,measurement objects are chosen from the neighboring cells of the best cell.The default value of this parameter is OFFSet this parameter through SET CORRMALGOSWITCH124
    • The flag of the priorityParameter ID: NPrioFlagValue range: FALSE, TRUEContent:FALSE: The priority of the neighboring cell is invalid. The neighboringcells whose priority flag is FALSE are the last ones to be consideredas the measurement objects in the neighboring cell combinationalgorithm.TRUE: The priority of the neighboring cell is valid in the neighboringcell combination algorithm. .The default value of this parameter is FALSESet this parameter through ADD INTRAFREQNCELL/MODINTRAFREQNCELL / ADD INTERFREQNCELL/MOD INTERFREQNCELL /ADD GSMNCELL/MOD GSMNCELLThe priority of neighbor cellParameter ID: NPrioValue range: 0 to 30The default value of this parameter is NoneContent:When The flag of the priority is TRUE, The priority of neighbor cell specifiesthe priority of neighboring cells. The smaller the parameter value is, the higherthe priority is and the more easily the neighboring cell is chosen as ameasurement object in the neighboring cell combination algorithm. Forexample, the neighboring cells with priority 1 are more easily chosen as themeasurement objects than the cells with priority 2 in the neighboring cellcombination algorithm.Set this parameter throughADD INTRAFREQNCELL/MOD INTRAFREQNCELL / ADDINTERFREQNCELL/MOD INTERFREQNCELL / ADD GSMNCELL/MODGSMNCELL125
    • Page60Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover1. Intra-Frequency Handover Overview2. Intra-Frequency Handover Procedure3. Signaling Procedures for Intra-Frequency Handover126
    • Page61Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.There are five types of signaling procedures for intra-frequency handover:• Intra-NodeB Intra-Frequency Soft Handover• Intra-RNC Inter-NodeB Intra-Frequency Soft Handover• Inter-RNC Intra-Frequency Soft Handover• Intra-RNC Inter-NodeB Intra-Frequency Hard Handover• Inter-RNC Intra-Frequency Hard HandoverSignaling Procedures for Intra-Frequency Handover127
    • Page62Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-NodeB Intra-Frequency Soft HandoverSignaling Procedures for Intra-Frequency Handover128
    • Page63Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-RNC Inter-NodeB Intra-Frequency Soft HandoverSignaling Procedures for Intra-Frequency Handover129
    • Page64Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RNC Intra-Frequency Soft HandoverSignaling Procedures for Intra-Frequency Handover130
    • Page65Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Intra-RNC Inter-NodeB Intra-Frequency Hard HandoverSignaling Procedures for Intra-Frequency Handover131
    • Page66Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover2. Inter-Frequency Handover3. Inter-RAT Handover132
    • Page67Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency HandoverInter-Frequency Handover OverviewInter-Frequency Handover ProcedureSignaling Procedures for Inter-Frequency Handover133
    • Page68Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-Frequency OverviewCharacters of Inter-Frequency Handover:The carrier frequency of the current cell and target cell are differentBased on the triggering causes of handover, inter-frequency handovercan be categorized into four types .Coverage-basedQoS-basedLoad-basedSpeed-basedCoverage-based inter-frequency handoverIf a moving UE leaves the coverage of the current frequency, the RNC needsto trigger the coverage-based inter-frequency handover to avoid call dropsQoS-based inter-frequency handoverAccording to the Link Stability Control Algorithm, the RNC needs to trigger theQoS-based inter-frequency handover to avoid call drops.Load-based inter-frequency blind handoverTo balance the load between inter-frequency con-coverage cells, the RNCchooses some UEs and performs the inter-frequency blind handoveraccording to user priorities and service priorities.Speed-based inter-frequency handoverWhen the Hierarchical Cell Structure (HCS) applies, the cells are divided intodifferent layers according to coverage. The macro cell has a larger coverageand a lower priority, whereas the micro cell has a smaller coverage and ahigher priority. Inter-frequency handover can be triggered by the UE speedestimation algorithm of the HCS. To reduce the frequencies of handover, theUE at a higher speed is handed over to a cell under a larger coverage,whereas the UE at a lower speed is handed over to a cell under a smallercoverage.134
    • Page69Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover135
    • The handover procedure is divided into four phases: handover triggering, handovermeasurement, handover decision, and handover execution.In the triggering phaseThe RNC notifies the UE to measure through an inter-frequency measurement controlmessage. If the quality of the pilot signal in the current cell deteriorates, the CPICH Ec/No orCPICH RSCP of the UMTS cell that the UE accesses is lower than the correspondingthreshold, and the UE reports event 2D.In the measurement phaseIf the RNC receives a report of event 2D, the RNC requests the NodeB and UE to start thecompressed mode to measure the qualities of inter-frequency neighboring cells, and the RNCsends an inter-frequency measurement control message.In the measurement phase, the method of either periodical measurement report or event-triggered measurement report can be used.In the decision phaseAfter the UE reports event 2B, the RNC performs the handover. Otherwise, the UE periodicallygenerates measurement reports, and the RNC makes a decision after evaluation.In the execution phaseThe RNC executes the handover procedure.Procedure of Coverage-based inter-frequency handover136
    • Page71Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.The estimated quality or strength of the currently used frequency is above acertain threshold.2FThe estimated quality or strength of the currently used frequency is below acertain threshold.2DDescriptionDescriptionEventEventMEASUREMENT EVENTSCoverage-based inter-frequency handoverWhen the estimated quality or strength of the currently used frequency is below a certain threshold,2DEvent will be triggered, Then RNC will initiate the compress Mode to start inter-frequency or inter-RAT handover measurement.During compress mode, if the the estimated quality of the currently used frequency is above a certainthreshold, 2F Event will be triggered, Then RNC will stop the compress Mode.137
    • Page72Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Compressed ModePurposeMeasure the inter-frequency cell or Inter-RAT cell under FDD modeCategoriesDownlink compressed modeUplink compressed modeRealization MethodsSF/2Higher layer schedulingCoverage-based inter-frequency handoverCompressed Mode control is a mechanism whereby certain idle periods are createdin radio frames during which the UE can perform measurements on other frequencies.The UE can carry out measurements in the neighbouring cell, such as GSM cell andFDD cell on other frequency. If the UE needs to measure the pilot signal strength ofan inter-frequency WCDMA or GSM cell and has one frequency receiver only, the UEmust use the compressed mode.Each physical frame can provide 3 to 7 timeslots for the inter-frequency or inter-RATcell measurement, which enhances the transmit capability of physical channels butreduces the volume of data traffic.In DL, during compressed mode ,UE receiver can test signal from other frequency. Inorder to avoid the effect cause by UE transmitter, compress mode is also used in UL.The compressed mode includes two types, spreading factor reduction (SF/2) and highlayer approaches. The usage of type of compressed mode is decided by the RNC,according to spreading factor used in uplink or downlink.138
    • Page73Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 2D is triggered on the basis of the following formula2D EVENTCoverage-based inter-frequency handoverQUsed <= TUsed2d - H2d/2QUsed is the measured quality of the used frequency.TUsed2d is the absolute quality threshold of the cell that uses the currentfrequency. Based on the service type (CS , PS domain R99 service, or PSdomain HSPA service) and measurement quantity (CPICH Ec/No or RSCP),this threshold can be configured through one of the following parameters:Inter-freq CS measure start Ec/No THDInter-freq R99 PS measure start Ec/No THDInter-freq H measure start Ec/No THDInter-freq CS measure start RSCP THDInter-freq R99 PS measure start RSCP THDInter-freq H measure start RSCP THDH2d is the event 2D hysteresis value 2D hysteresis.After the conditions of event 2D are fulfilled and maintained until the parameter 2Devent trigger delay time is reached, the UE reports the event 2D measurementreport message.Note:Any of the Ec/No and RSCP measurement result can trigger the 2D event.139
    • Page74Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInter-freq CS measure start Ec/No THDParameter ID: InterFreqCSThd2DEcNoThe default value of this parameter is -14dBInter-freq R99 PS measure start Ec/No THDParameter ID : InterFreqR99PsThd2DEcNoThe default value of this parameter is -14dBInter-freq H measure start Ec/No THDParameter ID : InterFreqHThd2DEcN0The default value of this parameter is -14dBInter-freq CS measure start Ec/No THDParameter ID: InterFreqCSThd2DEcNoValue range: –24 to 0 ,step :1dB.The default value of this parameter is -14dBContent: If the CS service uses Ec/No as a measurement quantity, the UE reports event 2D when themeasurement value is lower than the threshold. The RNC sends a message to enable the compressedmode and to start the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SETINTERFREQHOCOV .Inter-freq R99 PS measure start Ec/No THDParameter ID : InterFreqR99PsThd2DEcNoValue range: –24 to 0 ,step :1dB.The default value of this parameter is -14dBContent: If the PS domain R99 service uses Ec/No as a measurement quantity, the UE reports event 2Dwhen the measurement value is lower than the threshold. The RNC sends a message to enable thecompressed mode and to start the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SETINTERFREQHOCOVInter-freq H measure start Ec/No THDParameter ID : InterFreqHThd2DEcN0Value range: –24 to 0 ,step :1dB.The default value of this parameter is -14dBContent: For PS domain HSPA services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than thevalue of this parameter.Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SETINTERFREQHOCOV140
    • Page75Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInter-freq CS measure start RSCP THDParameter ID: InterFreqCSThd2DEcNoThe default value of this parameter is -95dBmInter-freq R99 PS measure start RSCP THDParameter ID : InterFreqCSThd2DRSCPThe default value of this parameter is -95dBmInter-freq H measure start RSCP THDParameter ID : InterFreqHThd2DRSCPThe default value of this parameter is -95dBmInter-freq CS measure start RSCP THDParameter ID: InterFreqCSThd2DEcNoValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -95dBmContent: If the CS service uses RSCP as a measurement quantity, the UE reports event 2Dwhen the measurement value is lower than the threshold. The RNC sends a message toenable the compressed mode and to start the inter-frequency measurement..Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV .Inter-freq R99 PS measure start RSCP THDParameter ID : InterFreqR99PsThd2DEcNoValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -95dBmContent: If the PS domain R99 service uses RSCP as a measurement quantity, the UEreports event 2D when the measurement value is lower than the threshold. The RNC sends amessage to enable the compressed mode and to start the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq H measure start RSCP THDParameter ID : InterFreqHThd2DRSCPValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -95dBmContent: For PS domain HSPA services, when RSCP is used as the measurement quantityfor inter-frequency measurement, the RNC sends the signaling to activate compressed modeand start inter-frequency measurement, if the UE reports the event 2D when the measuredvalue is smaller than the value of this parameter .Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV141
    • Page76Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handover2D hysteresisParameter ID: Hystfor2DThe default value of this parameter is 4 (2dB)2D event trigger delay timeParameter ID : TimeToTrig2DThe default value of this parameter is D320 (320 ms)2D hysteresisParameter ID: Hystfor2DValue range: 0 to 29 step :0.5dB.The default value of this parameter is 4 (2dB)Content: This parameter specifies the event 2D trigger hysteresis, which is relatedto slow fading. The greater the value of this parameter, the smaller the probability ofping-pong effect and misjudgment. In this case, however, the event cannot betriggered in time.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV .2D event trigger delay timeParameter ID : TimeToTrig2DValue range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320,D640, D1280, D2560, D5000The default value of this parameter is D320 (320 ms)Content: This parameter specifies the time of event 2D trigger delay, which isrelated to slow fading. The greater the value of this parameter, the smaller theprobability of misjudgment. In this case, however, the event responds to the changesof measured signals at a lower speed.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV142
    • Page77Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequencyhandover2F EVENTEvent 2F is triggered on the basis of the following formulaQUsed >= TUsed2d - H2d/2QUsed is the measured quality of the used frequency.TUsed2f is the absolute quality threshold of the cell that uses the current frequency.Based on the service type (CS , PS domain R99 service or PS domain HSPAservice) and measurement quantity (CPICH Ec/No or RSCP), this threshold can beconfigured through the following parameters:Inter-freq CS measure stop Ec/No THDInter-freq R99 PS measure stop Ec/No THDInter-freq H measure stop Ec/No THDInter-freq CS measure stop RSCP THDInter-freq R99 PS measure stop RSCP THDInter-freq H measure stop RSCP THDH2f is the event 2F hysteresis value 2F hysteresis.After the conditions of event 2F are fulfilled and maintained until the parameter 2Fevent trigger delay time is reached, the UE reports the event 2F measurementreport message.Note:Any of Ec/No and RSCP measurement result can trigger the 2F event.143
    • Page78Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInter-freq CS measure stop Ec/No THDParameter ID: InterFreqCSThd2FEcNoThe default value of this parameter is -12dBInter-freq R99 PS measure stop Ec/No THDParameter ID : InterFreqR99PsThd2FEcNoThe default value of this parameter is -12dBInter-freq H measure stop Ec/No THDParameter ID : InterFreqHThd2FEcN0The default value of this parameter is -12dBInter-freq CS measure stop Ec/No THDParameter ID: InterFreqCSThd2FEcNoValue range: –24 to 0 ,step :1dB.The default value of this parameter is -12dBContent: If the CS service uses Ec/No as a measurement quantity, the UE reports event 2Fwhen the measurement value is higher than the threshold. The RNC sends a message todisable the compressed mode and to stop the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq R99 PS measure stop Ec/No THDParameter ID : InterFreqR99PsThd2FEcNoValue range: –24 to 0 ,step :1dB.The default value of this parameter is -12dBContent: If the PS domain R99 service uses Ec/No as a measurement quantity, the UEreports event 2F when the measurement value is higher than the threshold. The RNC sends amessage to disable the compressed mode and to stop the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq H measure stop Ec/No THDParameter ID : InterFreqHThd2FEcN0Value range: –24 to 0 ,step :1dB.The default value of this parameter is -12dBContent: For PS domain HSPA services, when Ec/No is used as the measurement quantityfor inter-frequency measurement, the RNC sends the signaling to deactivate compressedmode and stop inter-frequency measurement, if the UE reports the event 2F when themeasured value is larger than the value of this parameter .Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV144
    • Page79Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInter-freq CS measure stop RSCP THDParameter ID: InterFreqCSThd2FRSCPThe default value of this parameter is -92 dBmInter-freq R99 PS measure stop RSCP THDParameter ID : InterFreqR99PsThd2FRSCPThe default value of this parameter is -92dBmInter-freq H measure stop RSCP THDParameter ID : InterFreqHThd2FRSCPThe default value of this parameter is -92dBmInter-freq CS measure stop RSCP THDParameter ID: InterFreqCSThd2FRSCPValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -92 dBmContent: If the CS service uses RSCP as a measurement quantity, the UE reports event 2Fwhen the measurement value is higher than the threshold. The RNC sends a message todisable the compressed mode and to stop the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV .Inter-freq R99 PS measure stop RSCP THDParameter ID : InterFreqR99PsThd2FRSCPValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -92dBmContent: If the PS domain R99 service uses RSCP as a measurement quantity, the UEreports event 2F when the measurement value is higher than the threshold. The RNC sends amessage to disable the compressed mode and to stop the inter-frequency measurement.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq H measure stop RSCP THDParameter ID : InterFreqHThd2FRSCPValue range: –115 to -25 dBm ,step :1dB.The default value of this parameter is -92dBmContent: For PS domain HSPA services, when RSCP is used as the measurement quantityfor inter-frequency measurement, the RNC sends the signaling to deactivate compressedmode and stop inter-frequency measurement, if the UE reports the event 2F when themeasured value is larger than the value of this parameter .Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV145
    • Page80Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handover2F hysteresisParameter ID: Hystfor2FThe default value of this parameter is 4 (2dB)2F event trigger delay timeParameter ID : TimeToTrig2DThe default value of this parameter is D1280 (1280 ms)2F hysteresisParameter ID: Hystfor2FValue range: 0 to 29 step :0.5dB.The default value of this parameter is 4 (2dB)Content: This parameter specifies the event 2F trigger hysteresis, which isrelated to slow fading. The greater the value of this parameter, the smallerthe probability of ping-pong effect and misjudgment. In this case, however,the event cannot be triggered in time.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV2F event trigger delay timeParameter ID : TimeToTrig2DValue range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200,D240, D320, D640, D1280, D2560, D5000The default value of this parameter is D1280 (1280 ms)Content: This parameter specifies the time of event 2F trigger delay, whichis related to slow fading. The greater the value of this parameter, the smallerthe probability of misjudgment. In this case, however, the event responds tothe changes of measured signals at a lower speed.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV146
    • Page81Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Handover MeasurementCoverage-based inter-frequency handoverUE RNCMeasurement reportPhysical Channel Recfg (CM)Measurement control (RSCP)2DPhysical Channel Recfg Complet(CM)Measurement control (Ec/No)When the UE enters the compress mode, RNC will trigger the inter-frequency handovermeasurement by two additional measurement control signaling , so as to request UEtest inter-frequency neighbor cell.In this Measurement control message, RNC should inform the UE inter-frequencymeasurement parameter (Neighbor list, reporting mode…)147
    • Page82Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverHandover MeasurementReport ModeUE RNCMeasurement control (Periodical, RSCP&Ec/No)Measurement reportHandoverMeasurement reportMeasurement reportUE RNCMeasurement control (Event triggering, RSCP)HandoverMeasurement report (2B RSCP or Ec/No)Periodical_reporting Event_triggerMeasurement control (Event triggering ,Ec/No)The measurement report mode of inter-frequency handover is configured through theparameter Inter-frequency measure report mode. By default ,periodically reportingis recommended.The advantage of periodical measurement report is that if the handover fails, the RNCreattempts the handover to the same cell after receiving the periodical measurementreport from the UE. This increases the probability of the success of inter-frequencyhandover.Based on the measurement control message received from the RNC, the UE periodicallyreports the measurement quality of the target cell. Then, based on the measurementreport, the RNC makes the handover decision and performs handover.148
    • Page83Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequencyhandoverInter-frequency measure report modeParameter ID: InterFreqReportModeThe default value of this parameter is Periodical reportingInter-frequency measure periodical rpt periodParameter ID: PeriodReportIntervalThe default value of this parameter is D500 (500 ms)Inter-freq measure timer lengthParameter ID: InterFreqMeasTimeThe default value of this parameter is 60 (60 s)Inter-frequency measure report modeParameter ID: InterFreqReportModeValue range :Periodical reporting, Event triggerThe default value of this parameter is Periodical reportingContent: This parameter specifies the inter-frequency measurement report mode.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-frequency measure periodical rpt periodParameter ID: PeriodReportIntervalValue range : NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000,12000, 16000, 20000, 24000, 28000, 32000, 64000The default value of this parameter is D500 (500ms)Content: This parameter specifies the interval of the inter-frequency measurement report.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq measure timer lengthParameter ID: PeriodReportIntervalValue range : 0 to 512 ,step 1sThe default value of this parameter is 60 ( 60s)Content: This parameter specifies the inter-frequency measurement timer length of the inter-frequency handover based on coverage or speed. This parameter has no effect on the inter-frequency measurement based on QoS.If no such type of inter-frequency handover occurs upon expiry of the inter-frequency measurement timer, the system stops the inter-frequencymeasurement and disables the compressed mode.If this parameter is set to 0, the RNC does not start the inter-frequencymeasurement timer. .Set this parameter for handover based on coverage through ADDCELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV149
    • Page84Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequencyhandoverHandover MeasurementEvent 2B is triggered on the basis of the following formulaQNoused >= TNoused2b + H2b/2QUsed <= TUsed2b - H2b/2QNoused is the measured quality of the cell that uses the other frequencies.TNoused2b is the absolute quality threshold of the cell that uses the other frequencies. Basedon the service type (CS , PS domain) and measurement quantity (CPICH Ec/No or RSCP),this threshold can be configured through the following parameters:Inter-freq CS target frequency trigger Ec/No THDInter-freq R99 PS target frequency trigger Ec/No THDInter-freq CS target frequency trigger RSCP THDInter-freq R99 PS target frequency trigger RSCP THD150
    • QUsed is the measured quality of the cell that uses the current frequency.TUsed2b is the absolute quality threshold of the cell that uses the current frequency.Based on the service type (CS service, PS domain service) and the measurement quantity(CPICH Ec/No or RSCP) in the coverage-based handover, TUsed2b can be configuredthrough the following parameters.If the event 2D with the CPICH RSCP value is received by the RNC,TUsed2b of event 2B with the CPICH RSCP value can be:Inter-freq CS Used frequency trigger RSCP THDInter-freq R99 PS Used frequency trigger RSCP THDTUsed2b of event 2B with the CPICH Ec/No value is configured as the maximum value 0dB according to 3GPP specification.If the event 2D with the CPICH Ec/No value is received by the RNC,TUsed2b of event 2B with the CPICH Ec/No value can be:Inter-freq CS Used frequency trigger Ec/No THDInter-freq R99 PS Used frequency trigger Ec/No THDTUsed2b of event 2B with the CPICH RSCP value is configured as the maximumvalue -25 dB according to 3GPP specification.H2b is the event 2B hysteresis value 2B hysteresis.151
    • Page86Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequencyHandoverInter-freq CS target frequency trigger Ec/No THDParameter ID: TargetFreqCsThdEcN0The default value of this parameter is –12 dBInter-freq CS Used frequency trigger Ec/No THDParameter ID: UsedFreqCSThdEcN0The default value of this parameter is –12 dBInter-freq CS target frequency trigger Ec/No THDParameter ID: TargetFreqCsThdEcN0Value range :–24 to 0, step 1dBThe default value of this parameter is –12 dBContent: If the CS service inter-frequency handover uses the event-triggered measurementreport mode, event 2B may be triggered when the Ec/No value of the target frequency ishigher than the threshold. In periodical measurement report mode, this parameter is used forhandover evaluation on the RNC side.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVInter-freq CS Used frequency trigger Ec/No THDParameter ID: UsedFreqCSThdEcN0Value range :–24 to 0, step 1dBThe default value of this parameter is –12 dBContent: If the CS service inter-frequency handover uses the event-triggered measurementreport mode, event 2B may be triggered when the Ec/No value of the used frequency is lowerthan the threshold.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOVEvent 2B is triggered only when the two necessary conditions are met at the same time.152
    • Page87Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequencyhandover2B Event default setting-12dB-12dBCS Ec/No thresholdUsed cellTarget cell-92dBm-92dBmPS RSCP threshold-92dBm-92dBmCS RSCP threshold-12dB-12dBPS Ec/No threshold153
    • Page88Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequencyhandover2B hysteresisParameter ID: Hystfor2BThe default value of this parameter is 4 (2dB)2B event trigger delay timeParameter ID: TimeToTrig2BThe default value of this parameter is D0 (0ms)2B hysteresisParameter ID: Hystfor2BValue range :0 to 29 , step 0.5dBThe default value of this parameter is 4 (2dB)Content: This parameter specifies the event 2B trigger hysteresis, which is relatedto slow fading. The greater the value of this parameter, the smaller the probability ofping-pong effect and misjudgment. In this case, however, the event cannot betriggered in time.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV2B event trigger delay timeParameter ID: TimeToTrig2BValue range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320,D640, D1280, D2560, D5000The default value of this parameter is D0 (0ms)Content: This parameter specifies the time of event 2B trigger delay, which isrelated to slow fading. The greater the value of this parameter, the smaller theprobability of misjudgment. In this case, however, the event responds to the changesof measured signals at a lower speed.Set this parameter through ADD CELLINTERFREQHOCOV/MODCELLINTERFREQHOCOV/SET INTERFREQHOCOV154
    • Page89Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverPeriodical Measurement Report ModeEvent-Triggered Measurement Report ModeHandover Decision and ExecutionThe coverage-based handover decision is categorized into two types according to thefollowing two measurement report modes: periodical measurement report modeand event-triggered measurement report mode. Each mode corresponds to adifferent decision and execution procedure.155
    • Page90Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverHandover Decision and ExecutionEvent-Triggered Measurement Report ModeBased on the event 2B measurement reports of CPICH RSCP andevent 2B CPICH Ec/No of the inter-frequency cellRNC process the report by following procedure:Add all the pilot cells that trigger event 2B to a cell set and arrange the cellsaccording to the measurement quality of CPICH_Ec/No in descendingorder.Select the cells in turn from the cell set to perform inter-frequency handover.156
    • Page91Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverHandover Decision and ExecutionPeriodical Measurement Report ModeMother_Freq + CIOother_Freq ≥ Tother_Freq + H/2Both the CPICH Ec/No value and CPICH RSCPvalue of the pilot signal of the target cell must meetthe requirementNOTE: No consideration of the current cellMother_Freq is the CPICH Ec/No or CPICH RSCP measurement value of thetarget cell reported by the UE. Both of the two measurement values of theinter-frequency cell must satisfy the formula.CIOother_Freq is the cell individual offset value of the target cell. It is equal tothe sum of Cell oriented Cell Individual Offset and Neigbhoring celloriented CIO.Tother_Freq is the decision threshold of inter-frequency hard handover.Based on the service type (CS or PS service) and measurement quantity (CPICHEc/No or CPICH RSCP), this threshold can be configured through the followingparameters:Inter-freq CS target frequency trigger Ec/No THDInter-freq R99 PS target frequency trigger Ec/No THDInter-freq H target frequency trigger Ec/No THDInter-freq CS target frequency trigger RSCP THDInter-freq R99 PS target frequency trigger RSCP THDInter-freq H target frequency trigger RSCP THDNOTE:These thresholds are the same as the quality threshold of event 2B.H is the inter-frequency hard handover hysteresis value HHO hysteresis.157
    • Page92Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverHandover Decision and ExecutionPeriodical Measurement Report ModeDecide whether both the CPICH Ec/No value and CPICH RSCP value ofthe pilot signal of the target cell meet the requirement of inter-frequencyhandover.Start the hard handover time-to-trigger timer, which is configured throughthe parameter HHO period trigger delay time.Select the cells in sequence, that is, from high quality cells to low qualityones, to initiate inter-frequency handover in the cells where the hardhandover time-to-trigger timer expires.158
    • Page93Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverCell oriented Cell Individual OffsetParameter ID: CIOThe default value of this parameter is 0 (0dB)Neigbhoring cell oriented CIOParameter ID: CIOOffsetThe default value of this parameter is 0 (0dB)HHO hysteresisParameter ID: HystForPrdInterFreqThe default value of this parameter is 0 (0dB)Cell oriented Cell Individual OffsetParameter ID: CIOValue range: -10 to +10Content: This parameter is used together with Neighboring cell oriented CIO. The sum of thetwo parameter values is added to the measurement quantity before the UE evaluates whetheran event occurred. In handover algorithms, this parameter is used for moving the border of acell.The default value of this parameter is 0 ( 0dB )Set this parameter through ADD CELLSETUP/MOD CELLSETUPNeigbhoring cell oriented CIOParameter ID: CIOOffsetValue range :–20 to +20 , step:0.5dBThe default value of this parameter is 0 (0dB)Content: The sum of the value of this parameter and the Cell oriented Cell Individual Offset specifiesthe offset of the cell CPICH measurement value. In handover algorithms, this parameter is used formoving the border of a cell.Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SETINTERFREQHOCOVHHO hysteresisParameter ID: HystForPrdInterFreqValue range 0 to 29 , step:0.5dBThe default value of this parameter is 0 (0dB)Content: This parameter is used to evaluate the inter-frequency handover on the RNC side. The greaterthe value of the parameter, the smaller the probability of the ping-pong effect and misjudgment. In thiscase, however, the speed of response to handover is lower.Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SETINTERFREQHOCOV159
    • Page94Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover160
    • The handover procedure is divided into four phases: handover triggering, handover measurement,handover decision, and handover execution.Besides the triggering step, the rest 3 steps are the same with Coverage-based inter-frequency handoverIn the triggering phaseIf the service quality of the current cell deteriorates, the Link Stability Control Algorithm makes a handovermeasurement decision.In the measurement phaseThe RNC requests the NodeB and the UE to start the compressed mode to measure the qualities of inter-frequency neighboring cells. Then, the RNC sends inter-frequency measurement control messages.In the measurement phase, the method of periodical measurement report or event-triggered measurementreport can be used.In the decision phaseAfter receiving the event 2B measurement reports of CPICH RSCP and CPICH Ec/No of the inter-frequency cell, the RNC performs the handover. Otherwise, the UE periodically generatesmeasurement reports, and the RNC makes a decision after evaluation.In the execution phaseThe RNC executes the handover procedure.Note :About “Link Stability Control Algorithm” :When the uplink transmit power of the UE or downlink transmitted code power of the NodeB exceeds theassociated threshold :For AMR, a fixed sequence of rate downsizing, inter-frequency handover, and then inter-RAT handoverare performed,for VP ,Inter-handover handover are performed,For BE service, rate downsizing, inter-frequency handover, and then inter-RAT handover are performedaccording to the configured sequenceProcedure of QoS-based inter-frequency handover :161
    • Page96Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInterFreq Handover Switch based on Uplink Traffic AMRParameter ID: UlQoSAmrInterFreqHoSwitchThe default value of this parameter is NOInterFreq Handover Switch based on Downlink Traffic AMRParameter ID: DlQoSAmrInterFreqHoSwitchThe default value of this parameter is NOInterFreq Handover Switch based on Uplink/Downlink Traffic AMRParameter ID : UlQoSAmrInterFreqHoSwitch/ DlQoSAmrInterFreqHoSwitchValue range NO, YESThe default value of this parameter is NOContent: If the value of this parameter is YES, inter-frequency handovercan be executed on the basis of the downlink/uplink QoS of AMR services.Set this parameter through SET QOSACT162
    • Page97Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInterFreq Handover Switch based on Uplink Traffic VPParameter ID: UlQoSVPInterFreqHoSwitchThe default value of this parameter is NOInterFreq Handover Switch based on Downlink Traffic VPParameter ID: DlQoSVPInterFreqHoSwitchThe default value of this parameter is NOInterFreq Handover Switch based on Uplink/Downlink Traffic VPParameter ID : UlQoSVPInterFreqHoSwitch/ DlQoSVPInterFreqHoSwitchValue range NO, YESThe default value of this parameter is NOContent: If the value of this parameter is YES, inter-frequency handovercan be executed on the basis of the downlink/uplink QoS of VP services.Set this parameter through SET QOSACT163
    • Page98Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverFirst / Second / Third Uplink QOS Enhancement Action for Traffic BEParameter ID: BeUlAct1/ BeUlAct2/ BeUlAct3The default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOFirst / Second / Third Downlink QOS Enhancement Action for Traffic BEParameter ID: BeDlAct1/ BeDlAct2/ BeDlAct3The default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOFirst / Second / Third Uplink QOS Enhancement Action for Traffic BEParameter ID : BeUlAct1/ BeUlAct2/ BeUlAct3Value range None, RateDegrade, InterFreqHO, InterRatHOThe default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOContent: This parameter defines the action sequence to enhance theUplink QoS of BE services .Set this parameter through SET QOSACTFirst / Second / Third Downlink QOS Enhancement Action for Traffic BEParameter ID : BeDlAct1/ BeDlAct2/ BeDlAct3Value range None, RateDegrade, InterFreqHO, InterRatHOThe default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOContent: This parameter defines the action sequence to enhance thedownlink QoS of BE services .Set this parameter through SET QOSACT164
    • Page99Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverDown Link QoS Measure timer lengthParameter ID: DLQoSMcTimerLenThe default value of this parameter is 20 (20s)Up Link QoS Measure timer lengthParameter ID: UpQoSMcTimerLenThe default value of this parameter is 20 (20s)Down Link QoS Measure timer lengthParameter ID : DLQoSMcTimerLenValue range 0 to 512 ,step 1sThe default value of this parameter is 20 (20s)Content: This parameter specifies the inter-frequency measurement timer length of the inter-frequency handover based on downlink QoS. This parameter has no effect on the inter-frequency measurement based on coverage.If no QoS-based inter-frequency handover occurs upon expiry of thedownlink inter-frequency measurement timer, the RNC stops the QoS-basedinter-frequency measurement.If this parameter is set to 0, the RNC does not start the inter-frequencyQoS-based measurement timer.Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHODown Link QoS Measure timer lengthParameter ID : UpQoSMcTimerLenValue range 0 to 512 ,step 1sThe default value of this parameter is 20 (20s)Content: This parameter specifies the inter-frequency measurement timer length of the inter-frequency handover based on uplink QoS. This parameter has no effect on the inter-frequency measurement based on coverage.If no QoS-based inter-frequency handover occurs upon expiry of the uplinkinter-frequency measurement timer, the RNC stops the inter-frequencymeasurement and disables the compressed mode.If this parameter is set to 0, the RNC does not start the inter-frequencyQoS-based measurement timer. .Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO165
    • Page100Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover166
    • The handover procedure is divided into three phases: handover triggering, handoverdecision, and handover executionThere is no measurement of the target cell, so we call it blind handover.In the triggering phaseThe Load Reshuffling (LDR) module directly determines whether the current cell isoverloaded and whether an inter-frequency handover needs to be performed. TheLDR module provides the target cell information for the current cell, and the RNCperforms the handover procedure.In the decision phaseThe RNC decides to trigger an inter-frequency blind handover if If the blindhandover neighbors are configured :After the inter-frequency handover is triggered, the RNC chooses a decisionalgorithm according to whether the conditions “Blind handover condition” ofdirect blind handover are met.If the value of the parameter of a cell is -115, the RNC performs directblind handover to this cell.If there is no such cell with the parameter value -115, the RNC initiatesan intra-frequency measurement for conditional blind handover.In the execution phaseThe RNC performs the blind handover according to the decision result.Procedure of Load-based inter-frequencyhandover :167
    • Page102Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Load-based inter-frequency handoverHandover triggeringTarget userUser with lower integrated priorityTarget cellBlind handover neighborBased on the service ARP, Traffic class, Channel type(R99, HSDPA), RNC willchoose the users with lower priority to execute handover .The target cell of this inter-frequency handover are only the blind handover neighborswith light load.which is indicated by the “Blind handover flag”168
    • Page103Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverBlind handover flagParameter ID: BlindHOFlagThe default value of this parameter is FalseCell oriented Cell Individual OffsetParameter ID : BlindHOFlagValue range FALSE, TRUEThe default value of this parameter is FALSEContent: This parameter indicates whether the neighboring cell is thetarget cell for blind handovers. If the value is TRUE, blind handovers can beperformed to the neighboring cell.Set this parameter through ADD INTERFREQNCELL/MODINTERFREQNCELL169
    • Page104Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Load-based inter-frequency handoverHandover Decision and ExecutionThe RNC determines to trigger an inter-frequency blind handoverRNC performs direct blind handover or conditional blind handoverAfter the RNC determines to trigger an inter-frequency blind handover ,according tothe parameter Blind handover condition, the RNC executes:If the value of the parameter of a cell is -115, the RNC performs direct blindhandover to this cell.If there is no such cell with the parameter value -115, the RNC initiates anintra-frequency measurement for conditional blind handover.Note:If the neighboring cells have the same Blind handover condition value, theRNC chooses any one of them.170
    • Page105Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Load-based inter-frequency handoverHandover Decision and ExecutionConditional Blind HandoverThe inter-frequency cells with the same coverage area have the same CPICHRSCP values. By measuring the CPICH RSCP of the current cell, the qualityof the cells with the same coverage area can be determined, which increasesthe probability of successful blind handoverThe intra-frequency measurement for conditional blind handover is described as follows:1.The RNC initializes the timer of intra-frequency measurement for blind handover. The timeris specified by internal algorithm and neednt to be configured.2. The RNC modifies the measurement mode:The measurement reporting mode is changed to periodic reporting by a newmeasurement control . The reporting period is Intrafrequency measurementreport interval of blind handover. The measurement reporting number isIntrafrequency measurement report amount of blind handover.The intra-frequency measurement quantity is CPICH RSCP.3. After receiving from the UE the intra-frequency measurement reports for conditional blindhandover, the RNC checks whether the following condition is met:CPICH RSCP of the cell in the measurement report >= Blind handover conditionIf the condition is met, the RNC increments the counter of the number of intra-frequency measurement reports for blind handover by 1. If the condition is not met,the RNC does not perform a blind handover to the cell that triggers LDR and stopsintra-frequency measurement for blind handover.When the counter reaches the value of Intrafrequency measurement reportamount of blind handover, the RNC initiates a blind handover to the cell thattriggers LDR.If the counter does not reach this value, the RNC waits for the next intra-frequencymeasurement report from the UE.If the timer of intra-frequency measurement for blind handover expires, the RNCdoes not perform a blind handover to the cell that triggers LDR and stops intra-frequency handover for blind handover.171
    • Page106Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverBlind handover conditionParameter ID: BlindHOQualityConditionThe default value of this parameter is -92 (-92dBm)Intrafrequency measurement report interval of blind handoverParameter ID: BlindHOIntrafreqMRIntervalThe default value of this parameter is D250 (250ms)Intrafrequency measurement report amount of blind handoverParameter ID: BlindHOIntrafreqMRAmountThe default value of this parameter is D2Blind handover conditionParameter ID : BlindHOQualityConditionValue range -115 to -25 , step:1dBThe default value of this parameter is -92 (-92dBm)Content: This parameter specifies whether the cell supports a direct or conditional blindhandover.The value -115 indicates that the cell supports a direct blind handover. Thisvalue is usually used in configuration of inter-frequency cells with largecoverage areas overlapped.The other values indicate that the cell supports a conditional blind handover.This value is usually used in configuration of inter-frequency cells with somecoverage areas overlapped.Set this parameter through ADD INTERFREQNCELL/MOD INTERFREQNCELLIntrafrequency measurement report interval of blind handoverParameter ID: BlindHOIntrafreqMRIntervalValue range D250, D500The default value of this parameter is D250 (250ms)Content: This parameter specifies the intra-frequency measurement period for blindhandover.Set this parameter through SET INTRAFREQHOIntrafrequency measurement report amount of blind handoverParameter ID: BlindHOIntrafreqMRAmountValue range D1, D2, D4, D8The default value of this parameter is D2Content: This parameter specifies the maximum number of intra-frequency measurementreports for blind handoverSet this parameter through SET INTRAFREQHO172
    • Page107Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover173
    • The handover procedure is divided into four phases: handover triggering, handover measurementhandover decision, and handover executionIn the triggering phaseThe RNC receives the internal handover request according to the HCS speed estimation. Thehandover based on HCS speed estimation is of two types:When the UE is in low-speed state, RNC will trigger handover from the macro cell to the microcell.When the UE is in high-speed state, RNC will trigger handover from the micro cell to the macrocell.For different types of handover, the RNC acts differently.In the measurement phaseIf the handover is performed from a macro cell to a micro cell, the RNC triggers compressedmode ,then sends an inter-frequency measurement control message for 2C event to start theinter-frequency measurement procedureIf the handover is performed from a micro cell to a macro cell, the RNC directly performs blindhandover, without measurement procedure. only if the handover fails, the RNC triggerscompressed mode ,then sends an inter-frequency measurement control message for 2C eventto start the inter-frequency measurement procedureIn the decision phaseFor handover from a macro cell to a micro cell, after the UE reports event 2C, the RNC performs thehandover decision.In the execution phaseThe RNC initiates a handover procedure.If the handover is performed from a micro cell to a macro cell and the target cell of blindhandover is configured, the RNC performs blind handover to the target cell.If the blind handover fails or the handover is performed from a macro cell to a micro cell, theRNC performs the inter-frequency handover procedure to the cell with the best quality afterreceiving event 2C from the UE.Procedure of Speed-based inter-frequency handover :174
    • Page109Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.The estimated quality of a non-used frequency is above a certainthreshold.2CDescriptionDescriptionEventEventMEASUREMENT EVENTSSpeed-based inter-frequency handoverEvent 2C is only used in Speed-based inter-frequency handover.After RNC believe the UE is in low-speed state, RNC will start handover from the macrocell to the micro cell.RNC triggers compressed mode firstly, then sends an inter-frequency measurementcontrol message for 2C event to start the inter-frequency measurement procedure.175
    • Page110Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 2C is triggered on the basis of the following formula2C EVENTSpeed-based inter-frequency handoverQNoused >= TNoused2c + H2c/22C only takes the Ec/No as the measurement quantityQNoused is the measured quality of the cell that uses the other frequencies.TNoused2c is the absolute quality threshold of the cell that uses the otherfrequencies, namely, Inter-freq measure target frequency trigger Ec/No THD.H2c is the event 2C hysteresis value 2C hysteresis.2C event trigger delay time is reached, the UE reports the event 2Cmeasurement report message.2C Event only takes the Ec/No as the measurement quantity.176
    • Page111Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverInter-freq measure target frequency trigger Ec/No THDParameter ID: InterFreqNCovHOThdEcN0The default value of this parameter is -16 (-16dB)2C hysteresisParameter ID: Hystfor2CThe default value of this parameter is 6 (3dB)2C event trigger delay timeParameter ID: TrigTime2CThe default value of this parameter is D640 (640ms)Inter-freq measure target frequency trigger Ec/No THDParameter ID : InterFreqNCovHOThdEcN0Value range -24 to 0, step:1dBThe default value of this parameter is -16 (-16dB),Content: When the Ec/No value of the target frequency is higher than the threshold, event2C can be triggeredSet this parameter through ADD CELLINTERFREQHONCOV/MODCELLINTERFREQHONCOV/SET INTERFREQHONCOV2C hysteresisParameter ID: Hystfor2CValue range 0 to 29The default value of this parameter is 6(3dB)Content: This parameter specifies the event 2C trigger hysteresis, which is related to slowfading. The greater the value of this parameter, the smaller the probability of ping-pong effectand misjudgment. In this case, however, the event cannot be triggered in time.Set this parameter through ADD CELLINTERFREQHONCOV/MODCELLINTERFREQHONCOV/SET INTERFREQHONCOV2C event trigger delay timeParameter ID: TrigTime2CValue range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640,D1280, D2560, D5000The default value of this parameter is D640 (640ms)Content: This parameter specifies the time of event 2C trigger delay, which is related toslow fading. The greater the value of this parameter, the smaller the probability ofmisjudgment. In this case, however, the event responds to the changes of measured signalsat a lower speed.Set this parameter through ADD CELLINTERFREQHONCOV/MODCELLINTERFREQHONCOV/SET INTERFREQHONCOV177
    • Page112Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover178
    • Page113Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Blind handover Based on Event 1FBlind HandoverHandover without measuring the neighboring cellLoad-based handoverSpeed-based handover from micro cell to macro cell1F event triggered inter-frequency handoverBlind handover is a special handover, means :before the handover, the UE needn’treport the target cell signal quality, RNC just select a target inter-frequency or inter-rat neighbor for the UE ,then force the UE handover to the target, the compressedmode and inter-frequency measurement can be overleapedThe precondition of blind handover is :the blind handover neighbors are configured toa cell (Blind handover flag ), which is discussed in the forenamed slides.Blind handover may be triggered by load, UE speed and also the 1F event179
    • Page114Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.A Primary CPICH becomes worse than an absolute threshold.1FDescriptionDescriptionEventEventMEASUREMENT EVENTSBlind handover Based on Event 1F1F Event is a intra-frequency measurement event, like 1A,1B,1C,1D.Events 1A,1B,1C,1D are used to trigger intra-frequency handover, Event 1F only triggerinter-frequency or inter-RAT blind handover.180
    • Page115Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 1F is triggered on the basis of the following formula1F EVENTBlind handover Based on Event 1FMOld <= T1f - H1f/2MOld is the measurement value of the cell that becomes worse.T1f is an absolute threshold. It is set to 1F event absolute EcNo threshold or 1Fevent absolute RSCP threshold respectively, depending on the measurementquantity.H1f is the event 1F hysteresis value 1F hysteresis.After the conditions of event 1F are fulfilled and maintained until the 1F eventtrigger delay time is reached, the UE reports the event 1F measurement reportmessage.181
    • Page116Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handover1F event absolute EcNo thresholdParameter ID: IntraAblThdFor1FEcNoThe default value of this parameter is -24 (-24dB)1F event absolute RSCP thresholdParameter ID: IntraAblThdFor1FRSCPThe default value of this parameter is -115 (-115dBm)1F event absolute EcNo thresholdParameter ID : IntraAblThdFor1FEcNoValue range -24 to 0, step:1dBThe default value of this parameter is -24 (-24dB),Content: This parameter specifies the absolute EcNo threshold of event 1F. Thegreater the parameter value is, the more easily event 1F is triggered. The smaller theparameter value is, the harder event 1F is triggered.Set this parameter through SET INTRAFREQHO/ADDCELLINTRAFREQHO/MOD CELLINTRAFREQHO1F event absolute RSCP threshold•Parameter ID: IntraAblThdFor1FRSCPValue range -115 to -25 step:1dBThe default value of this parameter is -115(-115dBm)Content: This parameter specifies the absolute RSCP threshold of event 1F. Thegreater the parameter value is, the more easily event 1F is triggered. The smaller theparameter value is, the harder event 1F is triggered.Set this parameter through ADD CELLINTERFREQHONCOV/MODCELLINTERFREQHONCOV/SET INTERFREQHONCOV182
    • Page117Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handover1F hysteresisParameter ID: HystFor1FThe default value of this parameter is 8 (4dB)1F event trigger delay timeParameter ID: TrigTime1FThe default value of this parameter is D640 (640 ms)1F hysteresisParameter ID : HystFor1FValue range 0 to 15, step:0.5dBThe default value of this parameter is 8 (4dB),Content: This parameter specifies the hysteresis value of event 1D. It is related to the slowfading characteristic. The greater the parameter value is, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time.Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MODCELLINTRAFREQHO•1F event trigger delay time•Parameter ID: TrigTime1FValue range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640,D1280, D2560, D5000The default value of this parameter is D640 (640 ms)Content: This parameter specifies the trigger delay time of event 1F. It is related to the slowfading characteristic. The greater the parameter value is, the smaller the misjudgmentprobability, but the slower the response of the event to the measured signal changes.Set this parameter through ADD CELLINTERFREQHONCOV/MODCELLINTERFREQHONCOV/SET INTERFREQHONCOV183
    • Page118Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover184
    • Page119Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-frequency Anti-PingPongThe inter-frequency anti-ping-pong algorithm is as follows:Step1-When a coverage-based inter-frequency handover or an inter-frequencyblind handover based on event 1F occurs, the RNC starts the timer specifiedby The timer length of anti ping-pong NCOV interfreq handover for the UEStep2-When a non-coverage-based inter-frequency handover is triggered, first,the RNC determines whether the timer specified by The timer length of antiping-pong NCOV interfreq handover expiresIf the timer does not expire, the RNC cancels the handoverIf the timer expires, the RNC performs the handoverParametersThe timer length of anti pingpong NCOV interfreq handoverParameter ID: 1FAntiPingPongtimerLengthThe default value of this parameter is 30sThe timer length of anti pingpong NCOV interfreq handoverParameter ID :IFAntiPingpangTimerLengthValue range:0~120Physical unit:sContent: the length of anti non-coverage based inter-frequency pingpong handover timer.Recommended value:30 Set this parameter through SET HOCOMM185
    • Page120Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure1. Coverage-based inter-frequency handover2. QoS-based inter-frequency handover3. Load-based inter-frequency handover4. Speed-based inter-frequency handover5. Blind handover Based on Event 1F6. Inter-frequency anti-PingPong7. Inter-frequency handover retry3. Signaling Procedures for Inter-Frequency Handover186
    • For the inter-frequency handover based on coverage or QoS, the following two parametersdetermine the retry period and the maximum number of retry times:2B event retry period2B event retry max timesFor the inter-frequency handover based on speed, the following two parameters determine theretry period and the maximum number of retry times:2C event retry period2C event retry max timesIf an inter-frequency handoverbased on event-triggeredmeasurement report mode fails, theRNC initiates the inter-frequencyhandover attempt according to aninter-frequency retry algorithmAfter the inter-frequency handoverfails, the retry timer for the cell isstarted. After the retry timer expires,the UE makes a handover attemptto the cell again until the retrynumber exceeds the maximumallowed retry number. If thehandover succeeds or two newevent 2B reports are received, theperiodical retry is stopped.Handoveris failedRetry conditionis satisfied?2B event? Start timerTriggerhandover2B measurementcontrol isre-transmittedEND Timer isexpiredimplementationInter-frequency handover retry187
    • Page122Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-frequency handover retryParameters2B event retry periodParameter ID: PeriodFor2BThe default value of this parameter is 500ms2B event retry max timesParameter ID: AmntOfRpt2BThe default value of this parameter is 63 (infinity)2C event retry periodParameter ID: PeriodFor2CThe default value of this parameter is 2s2C event retry max timesParameter ID: AmntOfRpt2CThe default value of this parameter is 52B event retry period2B event retry max timesSet above parameters through SET INTRERFREQHOCOV / ADDCELLINTERFREQHOCOV / MOD CELLINTERFREQHOCOV2C event retry period2C event retry max timesSet above parameters through SET INTRERFREQHONCOV / ADDCELLINTERFREQHONCOV / MOD CELLINTERFREQHONCOV188
    • Page123Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Inter-Frequency Handover1. Inter-Frequency Handover Overview2. Inter-Frequency Handover Procedure3. Signaling Procedures for Inter-Frequency Handover189
    • Intra-RNC Inter-Frequency Handover190
    • Inter-RNC Inter-Frequency Handover191
    • Page126Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Intra-Frequency Handover2. Inter-Frequency Handover3. Inter-RAT Handover192
    • Page127Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure3. Signaling Procedures for Inter-RAT Handover193
    • Page128Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewInter-RAT Handover Application ScenarioInter-RAT handover provides coverage expansion, load sharing, and layered services.It saves cost by utilizing the existing GSM network resources.Inter-RAT handover refers to the handover between UMTS and GSM. The reason forthe handover can be coverage limitation, link stability control or load limitation of the3G system.Inter-RAT handover can be UMTS-to-GSM or GSM-to-UMTS handover.Strategy of 2G and 3G cooperation is shown in the picture:Based on coverage, QoS , Service, load and speed, RNC can trigger UEhandover from 3G to 2G; When UE return back to Idle Mode, trigger UE Cellreselect to 3G.In this handover, however, GSM and UMTS dual-mode UEs (MSs) are required, andboth the GSM MSC and the GSM BSS must be upgraded.194
    • Page129Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewClassification of Inter-RAT Handover:Based on the triggering causes of handover, inter-frequencyhandover can be categorized into four types .Coverage-basedQoS-basedLoad-basedService-basedSpeed-basedCoverage-based inter-frequency handoverThe coverage of the UMTS is incontinuous at the initial stage of the 3G network. Onthe border of the coverage, the poor signal quality of UMTS triggers the UMTS-to-GSMmeasurement. If the signal quality of GSM is good enough and all the services of theUE are supported by the GSM, the coverage-based UMTS-to-GSM handover istriggered.QoS-based inter-frequency handoverAccording to the Link Stability Control Algorithm, the RNC needs to trigger the QoS-based UMTS-to-GSM handover to avoid call drops.Load-based inter-frequency blind handoverIf the load of the UMTS is heavy and all the RAB of a UE are supported by the GSM,the load-based UMTS-to-GSM handover is triggered.Service-based UMTS-to-GSM handoverBased on layered services, the traffic of different classes is handed over to differentsystems. For example, when an Adaptive Multi Rate (AMR) speech service isrequested, this service can be handed over to the GSM.Speed-based inter-frequency handoverWhen the Hierarchical Cell Structure (HCS) is used, the cells are divided into differentlayers on the basis of coverage. Typically, a marco cell has large coverage and lowpriority, whereas a micro cell has small coverage and high priority.UMTS-to-GSMhandover can be triggered by the UE speed estimation algorithm of the HCS. A UEmoving at high speed is handed over to a cell with larger coverage to reduce the timesof handover, whereas a UE moving at low speed is handed over to a cell with smallercoverage.195
    • Page130Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewPreconditions for UMTS-to-GSM Handover :Service Handover IndicatorCapabilities of Deciding UMTS-to-GSM HandoverGSM neighboring cell capabilityservice capabilityUE capabilityBefore handover, the RNC checks whether the preconditions meet the triggering requirementsof the UMTS-to-GSM handover. The preconditions include the service handover indicator,GSM cell capability, service capability, and UE capability.The parameter Service handover indicator indicates the CN policy for the service handoverto the GSM. This parameter is indicated in the Radio Access Bearer (RAB) assignmentsignaling assigned by the CN, or can be configured on the RNC side by ADD/MODTYPRABBASIC .Before deciding UMTS-to-GSM handover, the RNC considers GSM cell capability, servicecapability and UE capability.GSM cell capability could be “GSM”,”GPRS”,”EDGE”, it should be the real capability ofthe GSM neighbor, and configured in RNC data base by LMT correctlyService capability could be “GSM”,”GPRS”,”EDGE” also, it should be properlyconfigured in RNC data base by LMTUE capability is reported by the UE itself in “RRC Setup Complete” message.196
    • Page131Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewService Handover IndicatorHO_TO_GSM_SHOULD_BE_PERFORMHO_TO_GSM_SHOULD_NOT_BE_PERFORMHO_TO_GSM_SHALL_NOT_BE_PERFORMExample of rules for indicator of UMTS-to-GSM handover based on load and servicePreconditions for UMTS-to-GSM Handover :Before handover, the RNC checks service handover indicator, This parameter is indicated inthe Radio Access Bearer (RAB) assignment signaling assigned by the CNThe servicehandover indicators are as follows:HO_TO_GSM_SHOULD_BE_PERFORM: means that the handover to the 2G networkis performed when 2G signals are available.HO_TO_GSM_SHOULD_NOT_BE_PERFORM: means that the handover to the 2Gnetwork is performed when 3G signals are weak but 2G signals are strong.HO_TO_GSM_SHALL_NOT_BE_PERFORM: means that the handover to the 2Gnetwork is not performed even when 3G signals are weak but 2G signals are strong.197
    • For the UE accessing combined services (with CS services), the RNC sets theservice handover indicator of the UE to that of the CS service, because the CSservice has the highest QoS priority.For the UE accessing combined services (with only PS services), the RNC sets theservice handover indicator of the UE to that of the PS service, which has the highestQoS priority.If service handover indicators are not configured by the CN, each indictor can be setto Service parameter index of a service on the RNC.Based on different service handover indicators .RNC may initiate different action, forexample, handover based on service are not not performed for the services whosehandover indicator is “HO_TO_GSM_SHOULD_NOT_BE_PERFORM” or“HO_TO_GSM_SHALL_NOT_BE_PERFORM”198
    • Page133Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewPreconditions for UMTS-to-GSM Handover :Capabilities of Deciding UMTS-to-GSM HandoverGSM neighboring cell capabilityNO_CAPABILITY, GSM, GPRS, EDGEService required capabilityGSM, GPRS, EDGEUE capabilityGSM, GPRS, or EDGENote:For Service-Based UMTS-to-GSM Handover, thereis an additional switch on RNCThe rules for enabling UMTS-to-GSM handover are based on the parameter Service HandoverIndicator and the three types of capability parameters. The rules vary with different types ofinter-RAT handover , that is , the 4 factors will decide if the inter-RAT handover is allowed.The rules are:Coverage-based and QoS-based UMTS-to-GSM handoverwhen Service Handover Indicator is set as follows:HO_TO_GSM_SHOULD_BE_PERFORMHO_TO_GSM_SHOULD_NOT_BE_PERFORMIn addition, the RNC initiates inter-RAT handover based on the following capabilities:GSM cell capability (can be set on RNC)Service required capability (can be set on RNC)UE capability (reported from UE “RRC setup complete” message )199
    • GSM neighboring cell with EDGE capabilityNot allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedAllowedAllowedGPRSAllowedAllowedAllowedEDGEGSMGPRSEDGEService capability (required by 2G)UE CapabilityGSM neighboring cell with GPRS capabilityNot allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedAllowedAllowedGPRSAllowedAllowedAllowedEDGEGSMGPRSEDGEService capability (required by 2G)UE CapabilityGSM neighboring cell with GSM capabilityNot allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedNot allowedNot allowedGPRSAllowedNot allowedNot allowedEDGEGSMGPRSEDGEService capability (required by 2G)UE CapabilityIf the capability of all the GSM neighboring cells is "Nocapability", the inter-RAT handover cannot be started.200
    • load-based UMTS-to-GSM handoverwhen Service Handover Indicator is set as follows:HO_TO_GSM_SHOULD_BE_PERFORMHO_TO_GSM_SHOULD_NOT_BE_PERFORMservice-based UMTS-to-GSM handoverwhen Service Handover Indicator is set as follows:HO_TO_GSM_SHOULD_BE_PERFORMThe following switch are on:Inter-RAT CS handover switch (service based)Inter-RAT PS handover switch (service based)In addition, the RNC initiates inter-RAT handover based on the following capabilities:GSM cell capability (can be set on RNC)Service required capability (can be set on RNC)UE capability (reported from UE “RRC setup complete” message )GSM neighboring cell with EDGE capabilityNot allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedAllowedNot allowedGPRSAllowedAllowedAllowedEDGEGSMGPRSEDGEService capability (required by 2G)UE Capability201
    • GSM neighboring cell with GPRS capabilityGSM neighboring cell with GSM capabilityIf the capability of all the GSM neighboring cells is "Nocapability", the inter-RAT handover cannot be started.Not allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedAllowedNot allowedGPRSAllowedAllowedNot allowedEDGEGSMGPRSEDGEService capability (required by 2G)UE CapabilityNot allowedNot allowedNot allowedNot supported by 2GAllowedNot allowedNot allowedGSMAllowedNot allowedNot allowedGPRSAllowedNot allowedNot allowedEDGEGSMGPRSEDGEService capability (required by 2G)UE Capability202
    • Page137Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Inter-RAT Handover OverviewInter-RAT Handover RNC Algorithm SwitchINTER_RAT_PS_OUT_SWITCHDefault value is ONINTER_RAT_CS_OUT_SWITCHDefault value is ONThese switches are the parameter values of Handover algorithm switch in the command SETCORRMALGOSWITCH.INTER_RAT_PS_OUT_SWITCHThe switch decides whether the RNC will initiate inter-RATmeasurement to trigger inter-RAT handover of the PS domainfrom the UTRAN.INTER_RAT_CS_OUT_SWITCHThe switch decides whether the RNC will initiate inter-RATmeasurement to trigger inter-RAT handover of the CS domainfrom the UTRAN.Set this parameter through SET CORRMALGOSWITCH203
    • Page138Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover204
    • Page139Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-RAT handoverThe handover procedure is divided into four phases: handover triggering, handovermeasurement, handover decision, and handover execution.In the triggering phaseThe RNC sends a MEASUREEMNT CONTROL message to the UE, notifying the UE tomeasure the current carrier quality. This message defines the reporting rules and thresholdsof events 2D and 2F. If the quality of the pilot signal in the current cell deteriorates, the CPICHEc/No or CPICH RSCP of the UMTS cell that the UE accesses is lower than thecorresponding threshold and the UE reports event 2D.In the measurement phaseIf the RNC receives a report of event 2D, the RNC may request the NodeB and UE to start thecompressed mode to measure the qualities of GSM cells. Then, the RNC may send an inter-RAT measurement control message that defines the neighboring cell information, reportingperiod, and reporting rule.In the measurement phase, either periodical measurement report mode or event-triggeredmeasurement report mode can be used.In the decision phaseAfter the UE reports event 3A, the RNC makes a handover decision. Or, after the UEperiodically sends the measurement reports, the RNC evaluates the reports first and thenmakes a handover decision.In the execution phaseThe RNC initiates a handover procedure.205
    • Page140Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.The estimated quality of the currently used frequency is above a certainthreshold.2FThe estimated quality of the currently used frequency is below a certainthreshold.2DDescriptionDescriptionEventEventMEASUREMENT EVENTSCoverage-based inter-RAT handoverWhen the estimated quality of the currently used frequency is below a certain threshold,2D Eventwill be triggered, Then RNC will initiate the compress Mode to start inter-frequency or inter-RAT handover measurement.During compress mode, if the the estimated quality of the currently used frequency is above acertain threshold, 2F Event will be triggered, Then RNC will stop the compress Mode.206
    • Page141Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 2D is triggered on the basis of the following formula2D EVENTQUsed <= TUsed2d - H2d/2Coverage-based inter-RAT handoverQUsed is the measured quality of the used frequency.TUsed2d is the absolute quality threshold of the cell that uses the current frequency. Based on theservice type (CS , PS domain R99 service, or PS domain HSPA service) and measurement quantity(CPICH Ec/No or RSCP), this threshold can be configured through one of the following parameters:Inter-freq CS measure start Ec/No THDInter-freq R99 PS measure start Ec/No THDInter-freq H measure start Ec/No THDInter-freq CS measure start RSCP THDInter-freq R99 PS measure start RSCP THDInter-freq H measure start RSCP THDH2d is the event 2D hysteresis value 2D hysteresis.After the conditions of event 2D are fulfilled and maintained until the parameter 2D event triggerdelay time is reached, the UE reports the event 2D measurement report message.Note:Any of the Ec/No and RSCP measurement result can trigger the 2D event.207
    • Page142Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT CS measure start Ec/No THDThe default value of this parameter is -14dBInter-RAT R99 PS measure start Ec/No THDThe default value of this parameter is -15dBInter-RAT H measure start Ec/No THDThe default value of this parameter is -15dBInter-RAT CS measure start RSCP THDThe default value of this parameter is -95dBmInter-RAT R99 PS measure start RSCP THDThe default value of this parameter is -110dBmInter-RAT H measure start RSCP THDThe default value of this parameter is -110dBm2D hysteresisThe default value of this parameter is 4 (2dB)2D event trigger delay timeThe default value of this parameter is D320 (320 ms)The parameters for inter-RAT handover 2D are similar with inter-frequency handover.Set above parameters through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOV208
    • Page143Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 2F is triggered on the basis of the following formula2F EVENTQUsed >= TUsed2d - H2d/2Coverage-based inter-RAT handoverQUsed is the measured quality of the used frequency.TUsed2f is the absolute quality threshold of the cell that uses the current frequency. Based onthe service type (CS , PS domain R99 service or PS domain HSPA service) andmeasurement quantity (CPICH Ec/No or RSCP), this threshold can be configured throughthe following parameters:Inter-freq CS measure stop Ec/No THDInter-freq R99 PS measure stop Ec/No THDInter-freq H measure stop Ec/No THDInter-freq CS measure stop RSCP THDInter-freq R99 PS measure stop RSCP THDInter-freq H measure stop RSCP THDH2f is the event 2F hysteresis value 2F hysteresis.After the conditions of event 2F are fulfilled and maintained until the parameter 2F eventtrigger delay time is reached, the UE reports the event 2F measurement report message.Note:Any of the Ec/No and RSCP measurement result can trigger the 2F event.209
    • Page144Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-freq CS measure stop Ec/No THDThe default value of this parameter is -12dBInter-freq R99 PS measure stop Ec/No THDThe default value of this parameter is -13dBInter-RAT H measure stop Ec/No THDThe default value of this parameter is -13dBInter-freq CS measure stop RSCP THDThe default value of this parameter is -97 dBmInter-freq R99 PS measure stop RSCP THDThe default value of this parameter is -107dBmInter-RAT H measure stop RSCP THDThe default value of this parameter is -107dBm2F hysteresisThe default value of this parameter is 4 (2dB)2F event trigger delay timeThe default value of this parameter is D1280 (1280 ms)The parameters for inter-RAT handover 2D are similar with inter-frequency handover.Set above parameters through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOV210
    • Page145Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Interoperability Between Inter-RAT and Inter-Frequency HandoverCoverage-based inter-RAT handoverInter-frequency measurement2D, 2F EventInter-frequency neighborInter-RAT measurement2D, 2F EventInter-RAT neighborMeasure inter-RAT neighbor?Measureinter-frequencyneighbor?During the coverage-based and QoS-based UMTS-to-GSM handover, the measurements onboth inter-frequency and inter-RAT neighboring cells can be made, which enables the cellsto provide continuous coverage and high quality.The preconditions for the measurements are as follows:Both inter-frequency and inter-RAT neighboring cells are available.Inter-freq and Inter-RAT coexist switch is set to SIMINTERFREQRAT.If Inter-freq and Inter-RAT coexist switch is set as follows:Inter-frequency measurement, which means that the RNC allows the UE to perform onlythis type of measurement.Inter-RAT measurement, which means that the RNC allows the UE to perform only this typeof measurement.Concurrent inter-frequency and inter-RAT measurement, which means that the RNC allowsthe UE to perform both types of measurement in compressed mode at the same time.211
    • Page146Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-freq and Inter-RAT coexist switchParameter ID: InterFreqRATSwitchThe default value of this parameter is SIMINTERFREQRATInterFreq & InterRat coexist measure threshold choiceParameter ID: CoexistMeasThdChoiceThe default value of this parameter isCOEXIST_MEAS_THD_CHOICE_INTERFREQInter-freq and Inter-RAT coexist switchParameter ID : InterFreqRATSwitchValue range INTERFREQ, INTERRAT, SIMINTERFREQRATThe default value of this parameter is SIMINTERFREQRATContent: This parameter specifies the type of cells to be measured when inter-frequency and inter-RAT adjacent cells coexist:InterFreq: means that only the inter-frequency cells are measured and inter-frequency handover isperformed.InterRAT: means that only the GSM cells are measured and inter-RAT handover is performed.SimInterFreqRAT: means that both inter-frequency and inter-RAT cells are measured and inter-frequency or inter-RAT handover is performed according to the type of the cell that first meets thecondition for handover decision. If only the inter-frequency cells or inter-RAT cells exist, the value ofthis parameter is invalidSet this parameter through ADD CELLHOCOMM/MOD CELLHOCOMMDuring the concurrent inter-frequency and inter-RAT measurement, the values of the parameterInterFreq & InterRat coexist measure threshold choice for events 2D and 2F are chosen as follows:When the value COEXIST_MEAS_THD_CHOICE_INTERFREQ is chosen, the inter-frequencymeasurement threshold for event 2D is used.When the value COEXIST_MEAS_THD_CHOICE_INTERRAT is chosen, the inter-RAT measurementthreshold for event 2D is used.InterFreq & InterRat coexist measure threshold choice•Parameter ID: CoexistMeasThdChoiceValue range COEXIST_MEAS_THD_CHOICE_INTERFREQ,COEXIST_MEAS_THD_CHOICE_INTERRATThe default value of this parameter is COEXIST_MEAS_THD_CHOICE_INTERFREQContent: This parameter specifies the type of event 2D/2F measurement thresholds when inter-frequency and inter-RAT adjacent cells coexist.COEXIST_MEAS_THD_CHOICE_INTERFREQ: represents the event 2D/2F measurement thresholdfor the inter-frequency measurement.COEXIST_MEAS_THD_CHOICE_INTERRAT: represents the event 2D/2F measurement thresholdfor the inter-RAT measurement.Set this parameter through SET HOCOMM/ADD CELLHOCOMM/MOD CELLHOCOMM212
    • Page147Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Handover MeasurementCoverage-based inter-RAT handoverUE RNCMeasurement reportPhysical Channel Recfg (CM)Measurement control2DPhysical Channel Recfg Complet(CM)When the UE enters the compress mode, RNC will trigger the inter-RAT handover measurementby one additional measurement control signaling , so as to request UE test inter-RAT neighborcell.In this Measurement control message, RNC should inform the UE inter-RAT measurementparameter (Neighbor list, reporting mode…)213
    • Page148Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-RAT handoverUE RNCMeasurement reportHandoverMeasurement reportMeasurement reportUE RNCMeasurement control (Event triggering,GSM RSSI ,WCDMA RSCP or Ec/No)HandoverMeasurement report (3A)Periodical_reporting Event_triggerMeasurement control (Periodical, RSSI)Handover Measurement•Report ModeThe measurement report mode of inter-RAT handover is configured through the parameter Inter-frequency measure report mode. By default ,periodically reporting is recommended.Based on the measurement control message received from the RNC, the UE periodically reportsthe measurement quality of the target cell. Then, based on the measurement report, the RNCmakes the handover decision and performs handover.If the reporting mode is periodically reporting : UE only test the inter-RAT neighbor RSSI only.If the reporting mode is event trigger reporting : UE test the inter-RAT neighbor RSSI and currentcell Ec/No or RSCP ( depend on the 3A Measure Quantity ) .214
    • Page149Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT report modeParameter ID: InterRATReportModeThe default value of this parameter is Periodical reportingInter-RAT period report intervalParameter ID: InterRATPeriodReportIntervalThe default value of this parameter is D1000 (1000 ms)Inter-RAT report modeParameter ID: InterRATReportModeValue range :Periodical reporting, Event triggerThe default value of this parameter is Periodical reportingContent: This parameter specifies the inter-frequency measurement report mode.Set this parameter through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOVInter-RAT period report intervalParameter ID: InterRATPeriodReportIntervalValue range : NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000,12000, 16000, 20000, 24000, 28000, 32000, 64000The default value of this parameter is 1000 (500ms)Content: This parameter specifies the interval of the inter-frequency measurement report.Set this parameter through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOV215
    • Page150Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT measure timer lengthParameter ID: InterRATMeasTimeThe default value of this parameter is 60 (60 s)3A Measure QuantityParameter ID: MeasQuantityOf3AThe default value of this parameter is Auto (based on the 2D)Inter-RAT measure timer lengthParameter ID: InterRATMeasTimeValue range : 0 to 512 ,step 1sThe default value of this parameter is 60 ( 60s)Content: If no inter-RAT handover occurs upon expiry of the inter-RAT measurement timer,the system stops the inter-RAT measurement and disables the compressed mode. If thisparameter is 0, the system does not start the inter-RAT measurement timer.Set this parameter for handover based on coverage through ADDCELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV3A Measure QuantityParameter ID: MeasQuantityOf3AValue range : CPICH_Ec/No, CPICH_RSCP, AutoThe default value of this parameter is Auto (based on the 2D)Content: This parameter indicates the measurement value of the coverage-based inter-RATmeasurement in event-triggered measurement report mode.When 3A Measure Quantity is set to Auto, the measure quantity of the used UTRANfrequency is chosen the same as the measure quantity of the reporting 2D event thattriggered this inter-RAT measurement.Set this parameter through ADD CELLINTERRATHOCOV/MODCELLINTERFREQHOCOV/SET INTERRATHOCOVThis parameter can be configured only when Inter-RAT report mode is set toEVENT_TRIGGER.216
    • Page151Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-RAT handoverHandover measurementEvent-Triggered Measurement Report ModeEvent 3A is triggered on the basis of the following formula:– QUsed <= TUsed - H3a/2– MOtherRAT + CIOOtherRAT >= TOtherRAT + H3a/2QUsed is the measurement value of the cell at the currently used frequency.TUsed is the absolute quality threshold of the cell that uses the current frequency.217
    • Page152Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT CS Used frequency trigger Ec/No THDParameter ID: UsedFreqCsThdEcN0The default value of this parameter is –12 dBInter-RAT CS handover decision THDParameter ID: TargetRatCsThdThe default value of this parameter is 16 (-95 dBm)Inter-RAT CS Used frequency trigger Ec/No THDParameter ID: UsedFreqCsThdEcN0Value range :–24 to 0, step 1dBThe default value of this parameter is –12 dBContent: If CS service inter-RAT handover uses the event-triggered measurement reportmode, event 3A is triggered only when the Ec/No value of the used frequency is lower thanthis threshold.Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SETINTERRATHOCOVInter-RAT CS handover decision THDParameter ID: TargetRatCsThdValue range :0 to 63, step 1dBThe default value of this parameter is 16 (-95 dBm)Content: This parameter indicates the requirement of CS service inter-RAT handover for thequality of inter-RAT cells.If the event-triggered measurement report mode is used, event 3A may be triggered whenthe quality of the target frequency is higher than this threshold. In periodical measurementreport mode, this parameter is used to evaluate the coverage-based inter-RAT handover onthe RNC side.The value 0 means that the physical value is smaller than –110 dBm. .Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SETINTERRATHOCOV218
    • Page153Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handover3A Event default setting-95dBm-13dBPS Ec/No threshold-13dBH Ec/No threshold-12dBCS Ec/No thresholdTarget cellUsed cell-107dBmH RSCP threshold-95dBm-107dBmPS RSCP threshold-97dBmCS RSCP threshold219
    • Page154Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handover3A hysteresisParameter ID: Hystfor3AThe default value of this parameter is 4(2 dB)3A event trigger delay timeParameter ID: TrigTime3AThe default value of this parameter is D0 (0ms)3A hysteresisParameter ID: Hystfor3AValue range 0 to 15 , step 0.5dBThe default value of this parameter is 4 (2 dB)Content: This parameter specifies the event 3A trigger hysteresis, which is related toslow fading. The greater the value of this parameter, the smaller the probability ofping-pong effect and misjudgment. In this case, however, the event cannot betriggered in time .Set this parameter through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOV3A event trigger delay timeParameter ID: TrigTime3AValue range :D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320,D640, D1280, D2560, D5000The default value of this parameter is 0 ( 0ms )Content: This parameter specifies the time of event 3A trigger delay, which is relatedto slow fading. The greater the value of this parameter, the smaller the probability ofmisjudgment. In this case, however, the event responds to the changes of measuredsignals at a lower speed.Set this parameter through ADD CELLINTERRATHOCOV/MODCELLINTERRATHOCOV/SET INTERRATHOCOV220
    • Page155Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverCell Individual OffsetParameter ID: CIOThe default value of this parameter is 0 dBNeigbhoring cell oriented CIOParameter ID: CIOOffsetThe default value of this parameter is 0 dBCell Individual OffsetParameter ID: CIOValue range –50 to 50 , step 1dBThe default value of this parameter is 0 dBContent: This parameter cooperates with the Neighboring cell oriented CIOin inter-RAT handover decision. The larger the sum, the higher the handoverpriority of the GSM cell. The smaller the sum, the lower the handover priorityof the GSM cell.Set this parameter through ADD GSMCELL/MOD GSMCELLNeigbhoring cell oriented CIOParameter ID: CIOOffsetValue range :–50 to 50 , step 1dBThe default value of this parameter is 0 (0 dB)Content: This parameter is used in inter-RAT handover decision. The largerthe parameter, the higher the handover priority of the GSM cell. The smallerthe parameter, the lower the handover priority of the GSM cell .Set this parameter through ADD GSMNCELL/MOD GSMNCELL221
    • Page156Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based Inter-RAT handoverPeriodical Measurement Report ModeEvent-Triggered Measurement Report ModeHandover Decision and ExecutionThe coverage-based handover decision is categorized into two types according to thefollowing two measurement report modes: periodical measurement report mode andevent-triggered measurement report mode. Each mode corresponds to a different decisionand execution procedure.222
    • Page157Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-RAT handoverHandover Decision and ExecutionPeriodical Measurement Report ModeThe target cell must meet the requirement–– Mother_RAT + CIOother_RAT ≥ Tother_RAT + H/2NOTE: No consideration of the current cellMother_RAT is the measurement result of inter-RAT handover received by the RNC.CIOother_RAT is the cell individual offset value of the target cell. It is equal to the sum of Celloriented Cell Individual Offset and Neigbhoring cell oriented CIO. Neigbhoring cell orientedCIO indicates the offset of the measurement cell relative to the best cell.Tother_RAT is the decision threshold of inter-RAT hard handover.Based on the service type (CS or PS service) and measurement quantity (CPICH Ec/No or RSCP),this threshold can be configured through the following parameters:Inter-RAT CS handover decision THDInter-RAT R99 PS handover decision THDInter-RAT H handover decision THDNOTE:These thresholds are the same as the quality threshold of event 3A.For H is the inter-RAT handover hysteresis value Inter-RAT hysteresis.Select the cells in sequence, that is, from high quality cells to low quality ones, to initiate UMTS-to-GSM handover in the cells where the handover time-to-trigger timer expires.The length of the time-to-trigger timer is configured through the parameter Time to trigger forverified GSM cell (with BSIC acknowledged) or the parameter Time to trigger for non-verifiedGSM cell (with BSIC unacknowledged).223
    • Page158Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverTime to trigger for verified GSM cellParameter ID: TimeToTrigForVerifyThe default value of this parameter is 0 (0 ms)Time to trigger for non-verified GSM cellParameter ID: TimeToTrigForNonVerifyThe default value of this parameter is 65535 (never)Inter-RAT hysteresisParameter ID: HystforInterRATThe default value of this parameter is 0 (0dB)Time to trigger for verified GSM cellParameter ID : TimeToTrigForVerifyValue range 0 to 64000, step:1msThe default value of this parameter is 0 (0 ms)Content: This parameter specifies the delay time for triggering a GSM cell with BSIC acknowledged.In the period specified by this parameter, if the signal quality of an adjacent GSM cell meets therequirement of inter-RAT handover, and this cell is acknowledged, the network will start inter-RAThandover.Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SETINTERRATHOCOVTime to trigger for non-verified GSM cellParameter ID: TimeToTrigForNonVerifyValue range 0 to 64000 , 65535 , step:1msThe default value of this parameter is 65535 (never)Content: This parameter specifies the delay time for triggering a GSM cell with BSIC unacknowledged.In the period specified by this parameter, if the signal quality of an adjacent GSM cell meets therequirement of inter-RAT handover, and this cell is unacknowledged, the network will start inter-RAThandover.The value 65535 means that the RNC does not perform handover to an unacknowledged GSM cell. .Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SETINTERRATHOCOVInter-RAT hysteresisParameter ID: HystforInterRATValue range 0 to 15 , step:0.5dBThe default value of this parameter is 0 (0dB)Content: This parameter determines whether to trigger inter-RAT handover decision together with thequality threshold. The smaller the shadow fading, the smaller the value of this parameter.Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SETINTERRATHOCOV224
    • Page159Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Coverage-based inter-frequency handoverHandover Decision and ExecutionEvent-Triggered Measurement Report ModeBased on the event 3AAfter receiving the event 3A measurement report of GSM cells, the RNC performs thefollowing decision and execution procedures:Put all the GSM cells that trigger event 3A into a cell set and arrange the cells accordingto the measurement quality in descending order.Select the cells in sequence from the cell set to perform inter-RAT handover.225
    • Page160Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover226
    • The handover procedure is divided into four phases: handover triggering, handover measurement,handover decision, and handover execution.Besides the triggering step, the rest 3 steps are the same with Coverage-based inter-RAT handoverIn the triggering phaseIf the service quality of the current cell deteriorates, the Link Stability Control Algorithm makes a handovermeasurement decision.In the measurement phaseThe RNC requests the NodeB and the UE to start the compressed mode to measure the qualities of inter-frequency and inter-RAT neighboring cells. Then, the RNC sends measurement control messages forinter-frequency measurement and inter-RAT measurementIn the measurement phase, the method of periodical measurement report or event-triggered measurementreport can be used.In the decision phaseAfter the UE reports event 3A, the RNC performs the handover. Otherwise, the UE periodicallygenerates measurement reports, and the RNC makes a decision after evaluation.In theexecution phaseThe RNC executes the handover procedure.Note :About “Link Stability Control Algorithm” :When the uplink transmit power of the UE or downlink transmitted code power of the NodeB exceeds theassociated threshold :For AMR, a fixed sequence of rate downsizing, inter-frequency handover, and then inter-RAT handoverare performed,for VP ,inter-frequency handover are performed,For BE service, rate downsizing, inter-frequency handover, and then inter-RAT handover are performedaccording to the configured sequenceProcedure of QoS-based inter-RAT handover :227
    • Page162Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inRAT-frequency handoverInterRAT Handover Switch based on Uplink Traffic AMRParameter ID: UlQoSAmrInterRATHoSwitchThe default value of this parameter is NOInterRAT Handover Switch based on Downlink Traffic AMRParameter ID: DlQoSAmrInterRATHoSwitchThe default value of this parameter is NOInterRAT Handover Switch based on Uplink/Downlink Traffic AMRParameter ID : UlQoSAmrInterRATHoSwitch/ DlQoSAmrInterRATHoSwitchValue range NO, YESThe default value of this parameter is NOContent: If the value of this parameter is YES, inter-RAT handover can beexecuted on the basis of the downlink/uplink QoS of AMR services.Set this parameter through SET QOSACT228
    • Page163Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-frequency handoverFirst / Second / Third Uplink QOS Enhancement Action for Traffic BEParameter ID: BeUlAct1/ BeUlAct2/ BeUlAct3The default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOFirst / Second / Third Downlink QOS Enhancement Action for Traffic BEParameter ID: BeDlAct1/ BeDlAct2/ BeDlAct3The default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOFirst / Second / Third Uplink QOS Enhancement Action for Traffic BEParameter ID : BeUlAct1/ BeUlAct2/ BeUlAct3Value range None, RateDegrade, InterFreqHO, InterRatHOThe default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOContent: This parameter defines the action sequence to enhance the Uplink QoS ofBE services .Set this parameter through SET QOSACTFirst / Second / Third Downlink QOS Enhancement Action for Traffic BEParameter ID : BeDlAct1/ BeDlAct2/ BeDlAct3Value range None, RateDegrade, InterFreqHO, InterRatHOThe default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHOContent: This parameter defines the action sequence to enhance the downlink QoSof BE services .Set this parameter through SET QOSACT229
    • Page164Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverDown Link QoS Measure timer lengthParameter ID: DLQoSMcTimerLenThe default value of this parameter is 20 (20s)Up Link QoS Measure timer lengthParameter ID: UpQoSMcTimerLenThe default value of this parameter is 20 (20s)3A Used-Freq Measure Quantity for QoSParameter ID: UsedFreqMeasQuantityForQoS3AThe default value of this parameter is CPICH_RSCPThese two parameters are shared by QoS based inter-frequency and QoS basedinter-RAT handover:Down Link QoS Measure timer lengthUp Link QoS Measure timer lengthSet these parameters through ADD CELLQOSHO/MOD CELLQOSHO/SETQOSHO3A Used-Freq Measure Quantity for QoSParameter ID : UsedFreqMeasQuantityForQoS3AValue range CPICH_Ec/No, CPICH_RSCPThe default value of this parameter is CPICH_RSCPContent: This parameter indicates the measurement quantity used in QoS-basedUMTS-to-GSM measurement in event-triggered reporting mode.If the coverage and QoS-based UMTS-to-GSM handovers are triggeredsimultaneously, the RNC distributes QoS-based measurement parameters.Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO230
    • Page165Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover231
    • The handover procedure is divided into three phases: handover triggering, handover decision,and handover executionIn the triggering phaseWhen the load of the UMTS cell that the UE accesses is higher than the related threshold, theLoad Reshuffling (LDR) algorithm makes a handover decision.In the measurement phaseThe RNC enables the compressed mode and starts the inter-RAT handover measurement.In the decision phaseAfter the UE reports event 3C, the RNC makes a handover decision.In the execution phaseThe RNC initiates a handover procedure.Based on the service ARP, Traffic class, Channel type(R99, HSDPA), RNC will choose the userswith lower priority to execute handover .Procedure of Load-based inter-RAT handover :232
    • Page167Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT measure timer lengthParameter ID: InterRATMeasTimeThe default value of this parameter is 60 sInter-RAT measure timer lengthParameter ID : InterRATMeasTimeValue range 0 to 512The default value of this parameter is 60 sContent: If no inter-RAT handover occurs upon expiry of the inter-RATmeasurement timer, the system stops the inter-RAT measurement and disables thecompressed mode. If this parameter is 0, the system does not start the inter-RATmeasurement timer.Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHOCOV/SET INTERRATHONCOV233
    • Page168Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Event 3C is triggered on the basis of the following formula3C EVENTMOtherRAT + CIOOtherRAT >= TOtherRAT + H3c/2Load-based inter-RAT handoverMOtherRAT is the measurement value of the cell (in another RAT) in the reporting range.CIOOtherRAT is the cell individual offset value of the cell (in another RAT) in the reportingrange, which is equal to the sum of Cell oriented Cell Individual Offset and Neighboringcell oriented CIO.TOtherRAT is the absolute inter-RAT handover threshold. Based on the service type (CS , PSdomain R99 service, or PS domain HSPA service), this threshold can be configured throughthe following parameters:Inter-RAT CS handover decision THDInter-RAT R99 PS handover decision THDH3c is 3C hysteresis, the hysteresis value of event 3C.For the PS and CS combined services, the threshold(s) for CS services is (are) used.When the conditions for event 3C are met and the delay requirement specified by the 3Cevent trigger delay time parameter can be satisfied, the UE sends the measurementreport of event 3C.234
    • Page169Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT CS handover decision THDParameter ID: InterRATNCovHOCSThThe default value of this parameter is 21 (-90dBm)Inter-RAT PS handover decision THDParameter ID: InterRATNCovHOPSThdThe default value of this parameter is 21 (-90dBm)Inter-RAT CS handover decision THDParameter ID : InterRATNCovHOCSThValue range 0 to 63 ,step:1dBThe default value of this parameter is 21 (-90dBm)Content: This parameter is used to set measurement control on the event 3C. Theevent 3C is triggered when the quality of the target frequency is higher than thisthreshold. Note that the value 0 means the physical value is smaller than -110 dBm .Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHOCOV/SET INTERRATHONCOVInter-RAT PS handover decision THDParameter ID : InterRATNCovHOPSThValue range 0 to 63 ,step:1dBThe default value of this parameter is 21 (-90dBm)Content: This parameter is used to set measurement control on the event 3C. Theevent 3C is triggered when the quality of the target frequency is higher than thisthreshold. Note that the value 0 means the physical value is smaller than -110 dBm .Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHOCOV/SET INTERRATHONCOV235
    • Page170Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handover3C hysteresisParameter ID: Hystfor3CThe default value of this parameter is 0 dB3C event trigger delay timeParameter ID: TrigTime3CThe default value of this parameter is D640 (640 ms)3C hysteresisParameter ID : Hystfor3CValue range 0 to 15 ,step:0.5 dBThe default value of this parameter is 0 dBContent: This parameter specifies the event 3C trigger hysteresis, which is related to slowfading . The larger the value of this parameter, the smaller the probability of ping-pong effectand decision mistakes. In this case, however, event 3C cannot be triggered in time .Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHOCOV/SET INTERRATHONCOV3C event trigger delay timeParameter ID : TrigTime3CValue range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640,D1280, D2560, D5000The default value of this parameter is D640 (640 ms)Content: This parameter specifies the time of event 3C trigger delay, which is related toslow fading. The larger the value of this parameter, the smaller the probability of decisionmistakes. In this case, however, event 3C responds to the changes of measured signals moreslowly.Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHOCOV/SET INTERRATHONCOV236
    • Page171Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Load-based inter-RAT handoverDecision and Execution ProcedureDecision3C Eventload information interchanging between the 3G and 2G cellExecutionAfter receiving the event 3C measurement report of GSM cells, the RNC performs thefollowing handover decision and execution procedure:Put all the GSM cells that trigger event 3C into a cell set and arrange the cellsaccording to the measurement quality in descending order.Select the cells in sequence from the cell set.The load status between the source cell and the target cell can be acquired byinterchanging load information between a UMTS cell and a GSM cell during theload-based and service-based UMTS-to-GSM handover. Thus, whether to furtherconduct the handover can be determined to avoid the 2G cell overload andpossible handover to the congested cell.237
    • The procedure of load information interchanging between the 3G source cell and 2G target cellis described as follows:When the RNC sends a RELOCATION REQUIRED message to the 3G CN,If the switch Send Load Info to GSM Ind is set to ON, the RELOCATIONREQUIRED message includes the load information of the 3G source cell.If the switch Send Load Info to GSM Ind is set to OFF, then the RELOCATIONREQUIRED message does not include the InformationWhen the RNC receives the RELOCATION COMMAND message from the 2G CN,If the switch NCOV Reloc Ind based on GSM cell load is set to ON, the RNCobtains the load information of the 2G target cell by reading the RELOCATIONCOMMAND message.If the 2G load is lower than CS domain Reloc GSM load THD (for CSservice), or if the 2G load is lower than PS domain Reloc GSM load THD(for PS service), the RNC continues the inter-RAT handover procedure;otherwise, the RNC returns the RELOCATION CANCEL message to theCN to cancel this inter-RAT handover and makes another handoverattempt to the next candidate cell generated in the cell list based on inter-RAT measurement.If the load information of the 2G target cell is not included in theRELOCATION COMMAND message, the load information of the 2G targetcell is not considered and this inter-RAT handover is continued.If the switch NCOV Reloc Ind based on GSM cell load is set to OFF, the RNCcontinues the inter-RAT handover procedure without considering the thresholds.238
    • Page173Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverSend Load Info to GSM IndParameter ID: SndLdInfo2GsmIndThe default value of this parameter is ONNCOV Reloc Ind based on GSM cell loadParameter ID: NcovHoOn2GldIndThe default value of this parameter is ONSend Load Info to GSM IndParameter ID : SndLdInfo2GsmIndValue range ON, OFFThe default value of this parameter is ONContent:When the parameter is set to ON, the RNC sends UMTS cell loadinformation to the GSM CN during the non-coverage based systemrelocation in or out process.When the parameter is set to OFF, the RNC does not send UMTS cell loadinformation to the GSM during the system relocation in or out process.Set this parameter through SET INTERRATHONCOVNCOV Reloc Ind based on GSM cell loadParameter ID : NcovHoOn2GldIndValue range ON, OFFThe default value of this parameter is ONContent:When the parameter is set to ON, the RNC stops the non-coveragebased system relocation out process if the GSM cell load exceeds theCS dormain Reloc GSM load THD or PS dormain Reloc GSM loadTHD.When the parameter is set to OFF, the RNC continues the systemrelocation out process without considering the thresholds. Thisparameter specifies the time of event 3C trigger delay, which is relatedto slow fading. The larger the value of this parameter, the smaller theprobability of decision mistakes. In this case, however, event 3Cresponds to the changes of measured signals more slowly.Set this parameter through SET INTERRATHONCOV239
    • Page174Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverCS domain Reloc GSM load THDParameter ID: CSHOOut2GLoadThdThe default value of this parameter is 80 (80%)PS domain Reloc GSM load THDParameter ID: PSHOOut2GLoadThdThe default value of this parameter is 60 (60%)CS domain Reloc GSM load THDParameter ID : CSHOOut2GLoadThdValue range 0 to 100 ,step:1%The default value of this parameter is 80 (80%)Content:When the parameter is set to ON, the RNC sends UMTS cell loadinformation to the GSM CN during the non-coverage based systemrelocation in or out process.When the parameter is set to OFF, the RNC does not send UMTS cell loadinformation to the GSM during the system relocation in or out process.Set this parameter through SET INTERRATHONCOVPS domain Reloc GSM load THDParameter ID : PSHOOut2GLoadThdValue range 0 to 100 ,step:1%The default value of this parameter is 80 (80%)Content:When the parameter is set to ON, the RNC sends UMTS cell loadinformation to the GSM CN during the non-coverage based systemrelocation in or out process.When the parameter is set to OFF, the RNC does not send UMTS cell loadinformation to the GSM during the system relocation in or out process.Set this parameter through SET INTERRATHONCOV240
    • Page175Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT handover max attempt timesParameter ID: InterRATHOAttemptsThe default value of this parameter is 16Inter-RAT handover max attempt timesParameter ID : InterRATHOAttemptsValue range 1 to 16The default value of this parameter is 16Content: This parameter specifies the maximum number of attempts of load-basedand service-based inter-RAT handover.Set this parameter through ADD CELLINTERRATHONCOV/MODCELLINTERRATHONCOV/SET INTERRATHONCOV241
    • Page176Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover242
    • The handover procedure is divided into four phases: handover triggering, handover measurementhandover decision, and handover executionIn the triggering phaseWhen a service is established (RAB Assignment ), If the Service Handover Indicator is set toHO_TO_GSM_SHOULD_BE_PERFORM, the RNC requests the handover to the GSMIn the measurement phaseThe RNC enables the compressed mode and starts the inter-RAT handover measurement.In the decision phaseAfter the UE reports event 3C, the RNC makes a handover decision.In the execution phaseThe RNC initiates a handover procedure.service type is defined by parameters on cell level:Inter-RAT CS handover switch and Inter-RAT PS handover switchWhen a single CS service is initially set up by the UE, the RNC allows the UMTS-to-GSMservice-based handover if Inter-RAT CS handover switch is set to ON.When a single PS service is initially set up by the UE, the RNC allows the UMTS-to-GSMservice-based handover if Inter-RAT PS handover switch is set to ON.For the CS and PS combined services, no service-based handover is triggedservice handover indicator assigned by the Core Network. Only the services with the indicator“HO_TO_GSM_SHOULD_BE_PERFORM” can trigger Service-based inter-RAT handoverProcedure of Service-based inter-RAT handover :243
    • Page178Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverInter-RAT CS handover switchInter-RAT PS handover switchParameter ID:CSServiceHOSwitchPSServiceHOSwitchThe default value of this parameter is OFFInter-RAT CS handover switchInter-RAT PS handover switchParameter ID :CSServiceHOSwitchPSServiceHOSwitchValue range ON, OFFThe default value of this parameter is OFFContent:This parameter indicates whether the cell allows the service-basedinter-RAT handover for the CS or PS servicesSet this parameter through ADD CELLHOCOMM/MOD CELLHOCOMM244
    • Page179Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover245
    • Page180Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.VP service:•speech•videosUMTS-to-GSM Multimedia FallbackAMR service:•speechGSMWCDMAVP AMR AMRCompared with the traditional speech service of the GSM, the VP service of the UMTScan transmit not only speech services but also the images and videos captured byboth partiesFor the UMTS-to-GSM handover, network-initiated multimedia fallback on the followingoccasions:The RNC decides to send an inter-RAT handover request after receiving periodicalmeasurement reports or event 1F, 3A, or 3C.The service is combined with a VP, and the "Alternative RAB Para" in the RABASSIGNMENT message is a valid AMR speech format.246
    • The procedure for the fallback service is described as follows:In the service set up stage, the CN sends the SRNC a RANAP RAB ASSIGNMENTREQUIREMENT message to set up the VP service. The message includes the "AlternativeRAB Para" that has QoS parameters required for setting up the speech service.During UMTS-to-GSM handover, the SRNC sends a RANAP MODIFY REQUEST message tochange the VP service to the AMR speech service. In the 3GPP R6 protocol, the AlternativeRAB Configuration is also added to the RAB MODIFY REQUEST message, which enablesthe RNC to request the CN to change the VP service to the AMR speech service.The MSC initiates the Bearer Capability (BC) negotiation with the UE.After the negotiation is modified, the RNC is informed of performing service change. Themultimedia fallback ends when the service change is completed.When the multimedia fallback ends, the RNC decides whether to perform the UMTS-to-GSMhandover according to the current measurements reported by the UE.At the beginning of the service setup, the RNC saves the RAB Para and "Alternative RAB Para"in the RAB ASSIGNMENT or REQUEST RELOCATION REQUEST message. This makespreparations for notifying the CN of changing the VP service to the AMR speech service.The CN initiates the RAB reconfiguration to inform the two calling parties of performing themultimedia fallback. The multimedia fallback of the calling party is consistent with that of thecalled party. The single VP service falls back to the single AMR speech service. The multi-RAB service combined with VP falls back to the multi-RAB service combined with AMR. If themultimedia fallback succeeds, that is, the video phone in the service falls back to speechsuccessfully, the inter-RAT handover is initiated. Otherwise, the inter-RAT handover fails.Procedure of Multimedia Fallback247
    • Page182Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover248
    • Page183Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.PS UMTS-to-GSM Handover withNACCWhat is NACC?Network Assisted Cell ChangeWhat is the use of NACCTo reduce the delay of PS UMTS-to-GSM handoverNormal PS is realized by cell reselection, the time delay can not be guaranteed. ButSome PS services have requirements for the delay. If the handover takes too long,TCP may start slowly or data transmission of the stream service may beinterrupted due to the overflow of the UE buffer.The introduction of NACC enables the system information exchange between BSSand RAN , Thus the inter-system delay in PS domains, can be reduced.With NACC, the RNC sends the cell change order to the UE, which contains the GSMEDGE Radio Access Network (GERAN) system information, when the UMTS-to-GSM handover in the PS domain is triggered.249
    • After the SRNC receives a measurement report from the UE, the UE is reselectedto the GERAN cell according to the decision.The SRNC sends a RAN INFORMATION REQUEST message to the SGSN.The SGSN forwards the message to the corresponding BSS.The BSS sends a GERAN SI/PSI message to the SRNC via the SGSN. RANINFORMATION message can either be On-demand (single report) or On-modification (multiple reports).The SGSN forwards the report message to the SRNC through Iu interface.If there are several report messages, the SRNC terminates reporting by theTERMINATION/END message.To enable the NACC function, do as follows:Run the SET CORRMALGOSWITCH command to setPS_3G2G_CELLCHG_NACC_SWITCH to ON.Run the ADD GSMCELL/MOD GSMCELL command to set Inter-RAT cellsupport RIM indicator to TRUE.Procedure of NACC250
    • Page185Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Parameters of inter-RAT handoverPS 3G to 2G Cell change order NACC SwitchParameter ID: PS_3G2G_CELLCHG_NACC_SWITCHThe default value of this parameter is OFFInter-RAT cell support RIM indicatorParameter ID: SuppRIMFlagThe default value of this parameter is FALSEPS 3G to 2G Cell change order NACC SwitchParameter ID : PS_3G2G_CELLCHG_NACC_SWITCHValue range OFF, ONThe default value of this parameter is OFFContent: When it is checked, and inter-RAT handover of the PS domainfrom UTRAN use cell change order method, inter-RAT handover supportNACC(Network Assisted Cell Change) function.Set this parameter through SET CORRMALGOSWITCHInter-RAT cell support RIM indicatorParameter ID: SuppRIMFlagValue range FALSE, TRUEThe default value of this parameter FALSEContent: The parameter indicates whether the inter-RAT cell supports RIM.Set this parameter through ADD GSMCELL/MOD GSMCELL251
    • Page186Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure1. Coverage-based inter-RAT handover2. QoS-based inter-RAT handover3. Load-based inter-RAT handover4. Service-based inter-RAT handover5. UMTS-to-GSM Multimedia Fallback6. PS UMTS-to-GSM Handover with NACC7. UMTS-to-GSM Handover retry3. Signaling Procedures for Inter-RAT Handover252
    • Page187Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UMTS to GSM Handover RetryIn case of event triggered inter-RAT handover failure, if the causeof the failure is not a configuration failure and the retry timerexpires, the handover attempts to the cell again until the retrynumber exceeds the maximum retry number253
    • Page188Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.UMTS to GSM Handover RetryParameters3A event retry periodParameter ID: PeriodFor3AThe default value of this parameter is 1 (500ms)3A event retry max timesParameter ID: AmntOfRpt3AThe default value of this parameter is 63 (infinity)3C event retry periodParameter ID: PeriodFor3CThe default value of this parameter is 4 (2000ms)3C event retry max timesParameter ID: AmntOfRpt3CThe default value of this parameter is 53A event retry period3A event retry max timesSet this parameter through ADD CELLINTERRATHOCOV / MODCELLINTERRATHOCOV / SET INTERRATHOCOV3C event retry period3C event retry max timesSet this parameter through ADD CELLINTERRATHONCOV / MODCELLINTERRATHONCOV / SET INTERRATHONCOV254
    • Page189Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.Contents3. Inter-RAT Handover1. Inter-RAT Handover Overview2. Inter-RAT Handover Procedure3. Signaling Procedures for Inter-RAT Handover255
    • Page190Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.The signaling procedures for PS and CS inter-RAT handoverare different:• UMTS-to-GSM Handover in CS Domain• UMTS to GSM Handover in PS DomainSignaling Procedures for Inter-RAT Handover256
    • UMTS-to-GSM Handover in CS Domain257
    • UMTS-to-GSM Handover in CS Domain1. The SRNC sends the 3G MSC a RANAP message RELOCATION REQUIRED ifthe condition of inter-RAT outgoing handover is met.2. As indicated in the received message, the 3G MSC forwards this request to the 2GMSC on the MAP/E interface through a MAP message PREPARE HANDOVER.3. The 2G MSC forwards the request to the BSC. The message shown in the figure isfor reference only and is subject to the actual condition of the GSM.4. The BSC responds to this request. The message shown in the figure is for referenceonly and is subject to the actual condition of the GSM.5. Once the initial procedures are completed in the 2G MSC/BSS, the 2G MSC returnsa MAP/E message PREPARE HANDOVER RESPONSE.6. The 3G MSC sends the SRNC a RANAP message RELOCATION COMMAND.7. The SRNC sends the UE an RRC message HANDOVER FROM UTRAN throughthe existing RRC connection. This message may include information from one orseveral other systems.8. The BSC performs handover detection. The figure does not show such proceduresas GSM BSS synchronization. The message shown in the figure is for referenceonly and is subject to the actual condition of the GSM.9. The UE sends the BSC a HANDOVER COMPLETE message.10. The BSC sends the MSC a HANDOVER COMPLETE message. The messageshown in the figure is for reference only and is subject to the actual condition of theGSM.11. After detecting the UE in the coverage area of the GSM, the MSC sends the CN aMAP/E message SEND END SIGNAL REQUEST.12. The CN sends the former SRNC an IU RELEASE COMMAND message, requestingthe former SRNC to release the allocated resource.13. After the bearer resource is released in the UMTS, the former SRNC sends the CNan IU RELEASE COMPLETE message.14. After the call ends, the CN sends the MSC a MAP/E message SEND END SIGNALRESPONSE.258
    • UMTS-to-GSM Handover in PS DomainThe signal quality of the WCDMA cell where the UE camps on is dissatisfactory or the load ofthe serving cell is heavy.When the UE is in CELL_DCH state, the UTRAN sends a CELL CHANGE ORDER message tothe UE to perform a handover to GSM by cell reselection.The NodeB sends a RADIO LINK FAILURE INDICATION message, because the UE shuts downtransmission towards the WCDMA cell after cell reselection to a GSM cell.After the UE accesses a GSM cell, the SGSN directly sends an IU RELEASE COMMANDmessage to the SRNC, if the Packet Data Protocol (PDP) context does not need to betransferred.259
    • UMTS-to-GSM Handover in CS Domain1. The UE in CELL_DCH state or the UTRAN (when the UE is in CELL_FACH state)decides to initiate an inter-RAT handover in the PS domain to hand over the UE to anew GSM cell and stop the data transmission between the UE and the network.2. The UE sends a ROUTING AREA UPDATE REQUEST message to the 2G SGSN.The Update Type in the message indicates RA update, combined RA/LA update, orcombined RA/LA update with IMSI attach. The BSS adds the CGI including the RACand LAC of the cell to the received message before forwarding the message to anew 2G SGSN.3. The new 2G SGSN sends an SGSN CONTEXT REQUEST message to the old 3GSGSN to obtain the MM and PDP contexts. The old 3G SGSN validates the old P-TMSI Signature. If the old P-TMSI Signature is valid, the old 3G SGSN starts a timer.Otherwise, the old 3G SGSN responds with an error cause.4. If the UE stays in connected mode before handover, the old 3G SGSN sends anSRNS CONTEXT REQUEST message. After receiving this message, the SRNSbuffers the DPUs, stops sending the PDUs to the UE, and sends an SRNSCONTEXT RESPONSE message to the old 3G SGSN.5. The old 3G SGSN sends an SGSN CONTEXT RESPONSE message to the 2GSGSN, including the MM and PDP contexts.6. The security functions can be executed.7. The new 2G SGSN sends an SGSN CONTEXT ACKNOWLEDGE message to theold 3G SGSN. This informs the old 3G SGSN that the new 2G SGSN is ready toreceive the PDUs belonging to the activated PDP contexts.8. The old 3G SGSN sends a DATA FORWARD COMMAND message to the SRNS.The SRNS starts a data-forwarding timer and sends the buffered PDUs to the old3G SGSN.9. The old 3G SGSN tunnels the GTP PDUs to the new 2G SGSN. In the PDUs, thesequence numbers in the GTP header remain unchanged.10. The new 2G SGSN sends an UPDATE PDP CONTEXT REQUEST message toeach related GGSN. Each GGSN sends an UPDATE PDP CONTEXT RESPONSEmessage after updating its PDP context fields.11. The new 2G SGSN sends an UPDATE GPRS LOCATION message, requesting theHLR to modify the SGSN number.12. The HLR sends a CANCEL LOCATION message to the old 3G SGSN. The old 3GSGSN responds with a CANCEL LOCATION ACK message. After the timer expires,the old 3G SGSN removes the MM and PDP contexts.13. The old 3G SGSN sends an IU RELEASE COMMAND message to the SRNS. Afterthe data-forwarding timer expires, the SRNS responds with an IU RELEASECOMPLETE message.260
    • UMTS-to-GSM Handover in CS Domain14. The HLR sends an INSERT SUBSCRIBER DATA message to the new 2G SGSN.The 2G SGSN constructs an MM context and PDP contexts for the UE and returnsan INSERT SUBSCRIBER DATA ACK message to the HLR.15. The HLR sends an UPDATE GPRS LOCATION ACK message to the new 2GSGSN.16. If the association has to be established, the new 2G SGSN sends a LOCATIONUPDATE REQUEST message to the VLR. The VLR stores the SGSN number forcreating or updating the association.17. If the subscriber data in the VLR is marked as not confirmed by the HLR, the newVLR informs the HLR. The HLR cancels the old VLR and inserts subscriber data inthe new VLR.1. The new VLR sends an UPDATE LOCATION message to the HLR.2. The HLR cancels the data in the old VLR by sending a CANCELLOCATION message to the old VLR.3. The old VLR acknowledges the message by responding with aCANCEL LOCATION ACK message.4. The HLR sends an INSERT SUBSCRIBER DATA message to thenew VLR.5. The new VLR acknowledges the message by responding with anINSERT SUBSCRIBER DATA ACK message.6. The HLR responds with a UPDATE LOCATION ACK message to thenew VLR.18. The new VLR allocates a new TMSI and responds with a LOCATION UPDATEACCEPT message to the 2G SGSN.19. The new 2G SGSN checks the presence of the MS in the new RA. If all checks aresuccessful, the new 2G SGSN constructs the MM and PDP contexts for the MS. Alogical link is established between the new 2G SGSN and the UE. The 2G SGSNresponds to the UE with a ROUTING AREA UPDATE ACCEPT message.20. The UE acknowledges the new P-TMSI by returning a ROUTING AREA UPDATECOMPLETE message, including all PDUs successfully sent to the UE before therouting area update procedure.21. The new 2G SGSN sends a TMSI REALLOCATION COMPLETE message to thenew VLR if the UE confirms the VLR TMSI.22. The 2G SGSN and the BSS perform the BSS PACKET FLOW CONTEXTprocedure.261
    • Thank youwww.huawei.com262
    • www.huawei.comCopyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.WCDMA Load ControlThe WCDMA system is a self interference system. As the load of the WCDMA systemincreases, the interference rises. A relatively high interference may affect the coverageand Quality of Service (QoS) of established services. Therefore, capacity, coverage andQoS of the WCDMA system are mutually affected. The purpose of load control is tomaximize the system capacity while ensuring coverage and QoS.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.ObjectivesUpon completion of this course, you will be able to:Know load control principlesKnow load control realization methods in WCDMA systemKnow load control parameters in WCDMA system
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Load Control Overview2. Load Control Algorithms
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Load Control Overview1.1 Load Control Algorithms Overview1.2 Load Measurement1.3 Priorities Involved in Load Control
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load DefinitionLoad: the occupancy of capacityTwo kinds of capacity in WCDMA systemHard capacityCell DL OVSF CodeNodeB Transport resourceNodeB processing capability (NodeB credit)Soft capacityCell Power (UL and DL)WCDMA network load can be defined by 4 factors:1,Power ,include DL transmitting power of cell and increased UL interference (RTWP).2,DL OVSF code of a cell3,DL and UL NodeB processing capability which is defined by NodeB credit.4,Iub transmission bandwidth of a NodeBThe power resource is related to the mobility, distribution of the UE and also effected bythe radio conditions. Therefore, for a fixed power resource, the numbers of service canbe supported is not a fix result. We believe the UL and DL power resources are soft.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.The Objectives of Load ControlKeeping system stableMaximizing system capacity while ensuring coverage andQoSRealize different priorities for different service and differentuserWCDMA network load can be defined by 4 factors:1,Power ,include DL transmitting power of cell and increased UL interference (RTWP).2,DL OVSF code of a cell3,DL and UL NodeB processing capability which is defined by NodeB credit.4,Iub transmission bandwidth of a NodeBThe power resource is related to the mobility, distribution of the UE and also effectedby the radio conditions. Therefore, for a fixed power resource, the numbers of servicecan be supported is not a fix result. We believe the UL and DL power resources aresoft.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load Control AlgorithmsThe load control algorithms are applied to the differentUE access phases as follows:PUC: Potential User Control CAC: Call Admission ControlIAC: Intelligent Admission Control LDB : Intra-frequency Load BalancingLDR: Load Reshuffling OLC: Overload ControlThe load control algorithms are applied to the different UE access phases as follows:Before UE access: Potential User Control (PUC)During UE access: Intelligent Access Control (IAC) and Call Admission Control (CAC)After UE access: intra-frequency Load Balancing (LDB), Load Reshuffling (LDR), andOverload Control (OLC)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load Control AlgorithmsLoad control algorithm in the WCDMA systemThe load control algorithms are built into the RNC. The input of load control comesfrom the RNC and measurement information of the NodeB.RNC can calculate hard resource load, that is OVSF ,NodeB credit, Iub occupancy.The soft load need the NodeB reporting.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Load Control Overview1.1 Load Control Algorithms Overview1.2 Load Measurement1.3 Priorities Involved in Load Control
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Soft Load MeasurementThe major measurement objects of the load measurementReceived scheduled Enhanced Dedicated Channel (E-DCH)power share (RSEPS)•Uplink Received Total Wideband Power (RTWP)UL LoadHSDPA GBPHSDPA PBRNon-HSPA TCPDL LoadTCPE-DCH Provided Bit RateThe soft load control algorithms use load measurement values in the uplink and thedownlink. A common Load Measurement (LDM) algorithm is required to control loadmeasurement in the uplink and the downlink.The NodeB and the RNC perform measurements and filtering in accordance with theparameter settings. The statistics obtained after the measurements and filtering serveas the data input for the load control algorithms.The major measurement objects of the LDM are as follows:Uplink Received Total Wideband Power (RTWP)•Received scheduled Enhanced Dedicated Channel (E-DCH) power share (RSEPS)•E-DCH Provided Bit RateDownlink Transmitted Carrier Power (TCP)TCP of all codes not used for High Speed Physical Downlink Shared Channel (HS-PDSCH), High Speed Shared Control Channel , (Non-HSPA TCP)Provided Bit Rate on HS-DSCH (PBR)HS-DSCH required power ,also called Guaranteed Bit Rate (GBR) required power(GBP)
    • Based on the measurement parameters set on the NodeB Local Maintenance Terminal(LMT), the NodeB measures the major measurement quantities and then obtainsoriginal measurement values. After layer 3 filtering on the NodeB side, the NodeBreports the cell measurement values to the RNC.Based on the measurement parameters set on the RNC LMT, the RNC performssmooth filtering on the measurement values reported from the NodeB and then obtainsthe measurement values, which further serve as data input for the load controlalgorithms.Filtering on the NodeB SideA is the sampling value of the measurement.B is the measurement value after layer 1 filtering.C is the measurement value after layer 3 filtering ,which is the reported measurementvalueLayer 1 filtering is not standardized by protocols and it depends on vendor equipment.Layer 3 filtering is standardized. The filtering effect is controlled by a higher layer.Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load Measurement procedureSmooth Window Filtering on the RNC SideN : the size of the smooth window: the reported measurement value10( )Nn iiPP nN−−==∑nP
    • The interval at which the NodeB reports each measurement quantity to the RNC isconfigured by the Time unit and Report cycle on RNC LMT: SET LDMThe report interval = Time unit * Report cycleBy default, Time unit for all measurement are set to 10ms ;Report cycle forRTWP is 100, that is 1s; Report cycle for TCP and Non HSPA TCP is 20 ,that is200ms ;Report cycle for HSDPA GBP is 10, that is 100 ms; Report cycle forHSDPA PBR is 10, that is 100 msSmooth Window Filtering on the RNC SideAfter the RNC receives the measurement report, it filters the measurement valuewith the smooth window.Assuming that the reported measurement value is Qn and that the size of thesmooth window is N, the filtered measurement value is :Delay susceptibilities of PUC, CAC, LDB,LDR, and OLC to common measurementare different. The LDM algorithm must apply different smooth filter coefficients andmeasurement periods to those algorithms , on RNC LMT, we can set the smoothwindow length for different algorithms by SET LDM:The following table lists the parameters :251 to 32DlOLCAvgFilterLenDL OLC moving averagefilter length251 to 32UlOLCAvgFilterLenUL OLC moving averagefilter length31 to 32DlCACAvgFilterLenDL CAC moving averagefilter length31 to 32UlCACAvgFilterLenUL CAC moving averagefilter length251 to 32DlLdrAvgFilterLenDL LDR moving averagefilter length251 to 32UlLdrAvgFilterLenUL LDR moving averagefilter length321 to 32LdbAvgFilterLenLDB moving averagefilter length321 to 32PucAvgFilterLenPUC moving averagefilter lengthdefaultValueValueRangeParameter IDParameter NameSmooth window for GBP for all related algorithms are the same and the default setting is 1
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents1. Load Control Overview1.1 Load Control Algorithms Overview1.2 Load Measurement1.3 Priorities Involved in Load Control
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.PriorityThe service of user with low priority will be affected by theload control algorithms firstThree kinds of prioritiesUser PriorityRAB Integrate PriorityUser Integrate PriorityUser Priority: mainly applying to provide different QoS for different users. Eg., settingdifferent GBR according to the user priority for BE service. No consideration about theservice.RAB Integrate Priority: Priority of a service, related to the service type, and the userpriority of the user.User Integrate Priority: Only used for multi-RAB user ,it is a temporary priority of anongoing-service user.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.User PriorityThere are three levels of user prioritygold (high), silver (middle) and copper (low) user32kbps64kbps128kbpsUplinkCopperSilverGoldUser priority32kbps64kbps128kbpsDownlinkgolduserPay $100for 3GservicesIn CN HLR, we can set ARP (Allocation Retention Priority ), during service setup, CNsends ARP to RNC .Based on the mapping relation( configured in RNC), RNC canidentify the user is a gold, silver or copper one.The user priority affect GBR of BE service in RAN, Iub transmission management and soon.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.User PriorityThe mapping relation between user priority and ARP(Allocation/Retention Priority) is configured in RNC by SETUSERPRIORITYThe default relation is:CopperSilverGoldUserPriority151413121110987654321ARPThe user priority mapping can be configured in RNC by SET USERPRIORITYARP 15 is always the lowest priority and it cannot be configured. It corresponds tocopper.If ARP is not received in messages from the Iu interface, the user priority is regarded ascopper.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.RAB Integrate PriorityRAB Integrate Priority is mainly used in load controlalgorithmsRAB Integrate Priority are set according to :ARPTraffic ClassTHP(for interactive service only)HSPA or DCHRAB Integrate Priority is mainly used in load control algorithms.The values of RAB Integrate Priority are set according to the Integrate PriorityConfigured Reference parameter as follows:If Integrate Priority Configured Reference is set to Traffic Class, the integrate priorityabides by the following rules:Traffic classes: conversational -> streaming -> interactive -> background =>Services of the same class: Priority based on Allocation/Retention Priority (ARP)values, that is, ARP1 -> ARP2 -> ARP3 -> ... -> ARP14 =>Only for the interactive service of the same ARP value: priority based on TrafficHandling Priority (THP, defined in CN , sent to RNC during service setup), that is,THP1 -> THP2 -> THP3 -> ... -> THP14 =>Services of the same ARP, class and THP (only for interactive services): HighSpeed Packet Access (HSPA) or Dedicated Channel (DCH) service preferreddepending on the value of the Indicator of Carrier Type Priority parameter.
    • If Integrate Priority Configured Reference is set to ARP, the integrate priority abides bythe following rules:ARP1 -> ARP2 -> ARP3 -> ... -> ARP14 =>Traffic classes: conversational -> streaming -> interactive -> background =>Only for the interactive service of the same ARP value: priority based on TrafficHandling Priority (THP), that is, THP1 -> THP2 -> THP3 -> ... -> THP14 =>Services of the same ARP, class and THP (only for interactive services): HSPAor DCH service preferred depending on the value of the Indicator of CarrierType Priority parameter.Integrate Priority Configured Reference and Indicator of Carrier TypePriority are set by SET USERPRIORITY .By defaultIntegrate Priority Configured Reference is set to ARPIndicator of Carrier Type Priority is set to NONE, that means HSDPA and DCHservices have the same priority.ARP and THP are carried in the RAB ASSIGNMENT REQUEST message, and they arenot configurable on the RNC LMT.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Example for RAB Integrate PriorityDCHBackground2DDCHConversational2CHSDPAInteractive1BDCHInteractive1ABeartypeTraffic ClassARPServiceIDServices attribution in the cellBased on ARP, HSDPA priority is higherBased on Traffic Class, HSDPA priority is higherDCHBackground2DDCHConversational2CDCHInteractive1AHSDPAInteractive1BBeartypeTraffic ClassARPServiceIDBackgroundInteractiveInteractiveConversationalTraffic ClassDCH2DDCH1AHSDPA1BDCH2CBeartypeARPServiceIDThis example shows the RAB Integrate Priority calculation in 2 different conditions
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.User Integrate PriorityWhen the user has one RAB, User integrate priority is thesame as the RAB integrate priorityFor multiple RAB users, the integrate priority of the user isbased on the service of the highest priorityWhen the user has one RAB, User integrate priority is the same as the service of theRAB integrate priority;For multiple RAB users, the integrate priority of the user is based on the service of thehighest priority.User integrate priority is used in user-specific load control. For example, the selection ofR99 users during preemption, the selection of users during inter-frequency loadhandover for LDR, and the selection of users during switching BE services to CCH areperformed according to the user integrate priority.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Integrate Priority Configured ReferenceParameter ID: PRIORITYREFERENCEThe default value of this parameter is ARPIndicator of Carrier Type PriorityParameter ID: CARRIERTYPEPRIORINDThe default value of this parameter is NONEKey parameters of PriorityIntegrate Priority Configured ReferenceParameter ID: PRIORITYREFERENCEValue range: ARP, Traffic ClassContent: This parameter is used to set the criterion by which the priority is first sorted.The default value of this parameter is ARPSet this parameter through SET USERPRIORITYIndicator of Carrier Type PriorityParameter ID: CARRIERTYPEPRIORINDValue range: NONE, DCH, HSPAContent: This parameter is used to decide which carrier (DCH or HSPA) takesprecedence when ARP and Traffic Class are identical. When this parameter is set toNONE, the bearing priority of services on the DCH is the same as that of HSPAservices.The default value of this parameter is NONE,Set this parameter through SET USERPRIORITY
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.PUC PrinciplesThe Potential User Control (PUC) algorithm controls theInter-frequency cell reselection of the potential UE, andprevents UE from camping on a heavily loaded cell.Potential UE :IDLE Mode UECELL-FACH UE,CELL-PCH UE,URA-PCH UEThe function of PUC is to balance traffic load among inter-frequency cells. By modifyingcell selection and reselection parameters and broadcasting them through systeminformation, PUC leads UEs to cell with light load. The UE may be in idle mode,Cell_FACH state, Cell _PCH state, URA_PCH state
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.PUC Load JudgmentCell load for PUC is of three states: heavy, normal, and lightThe RNC periodically monitors the downlink load of the cell and compares themeasurement results with the configured thresholds Load level division threshold 1 andLoad level division threshold 2, that is, load level division upper and lower thresholds.If the cell load is higher than the load level division upper threshold plus the Load leveldivision hysteresis, the cell load is considered heavy.If the cell load is lower than the load level division lower threshold minus the Load leveldivision hysteresis, the cell load is considered light.Otherwise the cell load is considered normal
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.PUC ProcedureNodeB UEHeavy?Light?Normal?Cell TCPRNCThresholdcell reselectionparametersEvery 200msEvery 30 minutesSystem informationThe parameters related to cell selection and cell reselection are Qoffset1(s,n) (load leveloffset), Qoffset2(s,n) (load level offset), and Sintersearch (start threshold for inter-frequency cell reselection).The NodeB periodically reports the total TCP of the cell, and the PUC periodically triggersthe following activities:Assessing the cell load level based on the total TCPConfiguring Sintersearch, Qoffset1(s,n), and Qoffset2(s,n) based on the cell load levelPUC can Modify inter-frequency cell reselection parameters based on the load:1. Sintersearch :when the load of a cell is “Heavy”, PUC will increase Sintersearchwhen the load of a cell is “Light”, PUC will decrease Sintersearch2. QOffset:when the load of current cell is “Heavy” and neighbor is “Non heavy”, PUC will decreaseQOffsetwhen the load of current cell is “Non heavy” and neighbor is “Heavy”, PUC will increaseQOffsetUpdating the parameters of system information SIB3 and SIB11
    • →: indicates that the parameter value remains unchanged.↗: indicates that the parameter value increases.↘: indicates that the parameter value decreases.↗Sintersearch = Sintersearch + Sintersearch offset 2Heavy→Sintersearch = SintersearchNormal↘Sintersearch = Sintersearch + Sintersearch offset 1LightChange ofSintersearchSintersearchLoad of Current Cell
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.PUC PrinciplesFreq1Freq2System InfoSIB3,11System InfoSIB3,11System InfoSIB3,11Heavy loadLight load Normal loadIdle state CCH stateModify1.Easy to trigger reselection2.Easy to select light loadInter-freq neighbor CellDecrease the POTENTIAL loadModify1.Hard to trigger reselection2.Easy to camp on the cellIncrease the POTENTIAL loadStayBased on the characteristics of inter-frequency cell selection and reselection.SintersearchWhen this value is increased by the serving cell, the UE starts inter-frequency cellreselection ahead of schedule.When this value is decreased by the serving cell, the UE delays inter-frequencycell reselection.Qoffset1(s,n): applies to R (reselection) rule with CPICH RSCPWhen this value is increased by the serving cell, the UE has a lower probability ofselecting a neighboring cell.When this value is decreased by the serving cell, the UE has a higher probabilityof selecting a neighboring cell.Qoffset2(s,n): applies to R (reselection) rule with CPICH Ec/I0When this value is increased by the serving cell, the UE has a lower probability ofselecting a neighboring cell.When this value is decreased by the serving cell, the UE has a higher probabilityof selecting a neighboring cell.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell LDC algorithm switchParameter ID: NBMLDCALGOSWITCH PUCThe default value of this parameter is OffLoad level division threshold 1 (Heavy)Parameter ID: SPUCHEAVYThe default value of this parameter is 70(70%)Load level division threshold 2 (Light)Parameter ID: SPUCLIGHTThe default value of this parameter is 45(45%)Key parameters PUCCell LDC algorithm switchParameter ID: NBMLDCALGOSWITCH PUCValue range: OFF, ONContent: This parameter is used to enable or disable the PUC algorithm..The default value of this parameter is OFFSet this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH
    • Load level division threshold 1 (Heavy)Parameter ID: SPUCHEAVYValue range: 0 to 100Content: This parameter is one of the thresholds used to assess cell load level and todecide whether the cell load level is heavy or not.The default value of this parameter is 70%,Set this parameter through ADD CELLPUC / MOD CELLPUCLoad level division threshold 2 (Light)Parameter ID: SPUCLIGHTValue range: 0 to 100Content: This parameter is one of the thresholds used to assess cell load level and todecide whether the cell load level is heavy or not.The default value of this parameter is 45%,Set this parameter through ADD CELLPUC / MOD CELLPUC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load level division hysteresisParameter ID: SPUCHYSTThe default value of this parameter is 5 (5%)PUC period timer lengthParameter ID: PUCPERIODTIMERLENThe default value of this parameter is 1800(s)Key parameters PUCLoad level division hysteresisParameter ID: SPUCHYSTValue range: OFF, ONContent: This parameter specifies the hysteresis used during cell load levelassessment to avoid unnecessary ping-pong effect of a cell between two load levelsdue to a little load change.The default value of this parameter is 5 (5%)Set this parameter through ADD CELLPUC / MOD CELLPUCPUC period timer lengthParameter ID: PUCPERIODTIMERLENValue range: 6 to 86400 sContent: This parameter specifies the period of potential user control. The higher theparameter is set, the longer the period to trigger the PUC is.The default value of this parameter is 1800(s)Set this parameter through SET LDCPERIOD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Sintersearch offset 1Parameter ID: OFFSINTERLIGHTThe default value of this parameter is –2 (-4dB)Sintersearch offset 2Parameter ID: OFFSINTERHEAVYThe default value of this parameter is 2 (4dB)Key parameters PUCSintersearch offset 1Parameter ID: OFFSINTERLIGHTValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Sintersearch when the center cell loadlevel is "Light". It is strongly recommended that this parameter be set to a value nothigher than 0. The default value of this parameter is –2 (-4dB)Set this parameter through ADD CELLPUC / MOD CELLPUCSintersearch offset 2Parameter ID: OFFSINTERHEAVYValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Sintersearch when the center cell loadlevel is "Heavy". It is strongly recommended that this parameter be set to a value notlower than 0. The default value of this parameter is 2 (4dB)Set this parameter through ADD CELLPUC / MOD CELLPUC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Qoffset1 offset 1Parameter ID: OFFQOFFSET1LIGHTThe default value of this parameter is –4 (-8dB)Qoffset1 offset 2Parameter ID: OFFQOFFSET1HEAVYThe default value of this parameter is 4 (8dB)Key parameters PUCQoffset1 offset 1Parameter ID: OFFQOFFSET1LIGHTValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Qoffset1(RSCP) when the currentcell has heavy load and the neighboring cell has light or normal load. To enable theUE to select a neighboring cell with relatively light load, it is strongly recommendedthat this parameter be set to a value not higher than 0.The default value of this parameter is -4 (-8dB)Set this parameter through ADD CELLPUC/MOD CELLPUCQoffset1 offset 2Parameter ID: OFFQOFFSET1HEAVYValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Qoffset1(RSCP) when the load of aneighboring cell is heavier than that of the center cell. To enable the UE to select aneighboring cell with relatively light load, it is strongly recommended that thisparameter be set to a value not lower than 0.The default value of this parameter is 4 (8dB)Set this parameter through ADD CELLPUC/MOD CELLPUC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Qoffset2 offset 1Parameter ID: OFFQOFFSET2LIGHTThe default value of this parameter is –4 (-8dB)Qoffset2 offset 2Parameter ID: OFFQOFFSET2HEAVYThe default value of this parameter is 4 (8dB)Key parameters PUCQoffset1 offset 1Parameter ID: OFFQOFFSET1LIGHTValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Qoffset1(RSCP) when the current cellhas heavy load and the neighboring cell has light or normal load. To enable the UE toselect a neighboring cell with relatively light load, it is strongly recommended that thisparameter be set to a value not higher than 0.The default value of this parameter is -4 (-8dB)Set this parameter through ADD CELLPUC/MOD CELLPUCQoffset1 offset 2Parameter ID: OFFQOFFSET2HEAVYValue range: –10 to 10 ,step:2dBContent: This parameter defines the offset of Qoffset2(EcNo) when the load of aneighboring cell is heavier than that of the center cell. To enable the UE to select aneighboring cell with relatively light load, it is strongly recommended that thisparameter be set to a value not lower than 0.The default value of this parameter is 4 (8dB)Set this parameter through ADD CELLPUC / MOD CELLPUC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Intra-Frequency Load BalancingIntra-frequency Load Balancing (LDB) is performed to adjustthe coverage areas of cells by modifying PCPICH powerLDB affect UEs in all statesIntra-frequency Load Balancing (LDB) is performed to adjust the coverage areas ofcells according to the measured values of cell downlink power load. RNC checks theload of cells periodically and adjusts the transmit power of the P-CPICH in theassociated cells based on the cell load.When the load of a cell increases, the cell reduces its coverage to lighten its load.When the load of a cell decreases, the cell extends its coverage so that some traffic isoff-loaded from its neighboring cells to it.Reduction of the pilot power will make the UEs at the edge of the cell handed over toneighboring cells, especially to those with a relatively light load and with relatively highpilot power. After that, the downlink load of the cell is lightened accordingly.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDB ProcedureNodeB UEHeavy?Light?Normal?Cell TCPRNCThresholdModify cell PCPICHpowerUpdated PCPICHPOWERHandover orCell ReselectionThe NodeB periodically reports the total TCP of the cell, and the LDB periodically triggersthe following activities:Assessing the cell load level based on the total TCPIf the downlink load of a cell is higher than the value of the Cell overload threshold, it isan indication that the cell is heavily loaded. In this case, the transmit power of the P-CPICH needs to be reduced by a step, which is defined by the Pilot power adjustmentstep parameter. However, if the current transmit power is equal to the value of the Mintransmit power of PCPICH parameter, no adjustment is performed.If the downlink load of a cell is lower than the value of the Cell underload threshold, it isan indication that the cell has sufficient remaining capacity for more load. In this case, thetransmit power of the P-CPICH increases by a step, which is defined by the Pilot poweradjustment step parameter, to help to lighten the load of neighboring cells. However, ifthe current transmit power is equal to the value of the Max transmit power of PCPICHparameter, no adjustment is performed.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell LDC algorithm switchParameter ID: NBMLdcAlgoSwitch LDBThe default value of this parameter is OffIntra-frequency LDB period timer lengthParameter ID: IntraFreqLdbPeriodTimerLenThe default value of this parameter is 1800 (s)Key parameters LDBCell LDC algorithm switchParameter ID: NBMLdcAlgoSwitch LDBValue range: OFF, ONContent: This parameter is used to enable or disable the LDB algorithm..The default value of this parameter is OFFSet this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCHIntra-frequency LDB period timer lengthParameter ID: IntraFreqLdbPeriodTimerLenValue range: 0 to 86400Content: This parameter specifies the length of the intra-frequency LDB period.The default value of this parameter is 1800 (s)Set this parameter through SET LDCPERIOD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell overload threshold (Heavy)Parameter ID: CellOverrunThdThe default value of this parameter is 90(90%)Cell underload threshold (Light)Parameter ID: CellUnderrunThdThe default value of this parameter is 30(30%)Key parameters LDBCell overload thresholdParameter ID: CellOverrunThdValue range: 0 to 100Content: If the downlink load of a cell exceeds this threshold, the algorithm candecrease the pilot transmit power of the cell so as to extend the capacity of the wholesystem.The default value of this parameter is 90%,Set this parameter through ADD CELLLDB / MOD CELLLDBCell underload thresholdParameter ID: CellUnderrunThdValue range: 0 to 100Content: If the downlink load of a cell is lower than this threshold, the algorithm canincrease the pilot transmit power of the cell so as to share the load of other cells.The default value of this parameter is 30%,Set this parameter through ADD CELLLDB / MOD CELLLDB
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Pilot power adjustment stepParameter ID: PCPICHPowerPaceThe default value of this parameter is 2 (0.2dB)Max transmit power of PCPICHParameter ID: MaxPCPICHPowerThe default value of this parameter is 346 (34.6dBm)Key parameters LDBPilot power adjustment stepParameter ID: PCPICHPowerPaceValue range: 0 to 10 , Step 0.1dBContent: This parameter defines the step for the adjustment to the pilot power.The default value of this parameter is 2, 0.2dBSet this parameter through ADD CELLLDB / MOD CELLLDBMax transmit power of PCPICHParameter ID: MaxPCPICHPowerValue range: –100 to 500 ,Step 0.1dBContent: This parameter defines the maximum transmit power of the P-CPICH in a cell.This parameter has to be set according to the actual system environment, that is, forexample, cell coverage (radius) and geographical environment. If the maximum transmitpower of the P-CPICH is set too low, the cell coverage decreases. When a certainproportion of soft handover area is ensured, any more increase in the pilot powerachieves no improvement on the performance of the downlink coverage.The default value of this parameter is 346 (34.6dBm)Set this parameter through ADD PCPICH / MOD PCPICHPWR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Min transmit power of PCPICHParameter ID: MinPCPICHPowerThe default value of this parameter is 313 (31.3dBm)Key parameters LDBMin transmit power of PCPICHParameter ID: MinPCPICHPowerValue range: -100 to 500Content: This parameter defines the minimum transmit power of the P-CPICH in a cell.This parameter has to be set according to the actual system environment, that is, forexample, (radius) and geographical environment. If the minimum transmit power of theP-CPICH is set too low, the cell coverage will be affected. The parameter has to be setunder the condition that a certain proportion of soft handover area is ensured or theoccurrence of coverage hole can be prevented.The default value of this parameter is 313 (31.3dBm)Set this parameter through ADD PCPICH / MOD PCPICHPWR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Why we need CAC?WCDMA is an interference limited system, after a new call isadmitted, the system load will be increasedIf a cell is high loaded, a new call will cause ongoing userdroppedWe must keep the coverage planned by the Radio NetworkPlanningCAC is needed under such scenarios:1. RRC connection setup request2. RAB setup and Bandwidth increasing3. Handover4. RB reconfiguration
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Flow chart of CACThe admission decision is based on:• Cell available code resource: managed in RNC• Cell available power resource, that is DL/UL load : measured in NodeB• NodeB resource state, that is, NodeB credits : managed in RNC• Available Iub transport layer resource, that is, Iub transmission bandwidth:managed in RNC• HSPA user number (only for HSPA service)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Admission control Switches can be set on RNC LMT:Power CACUplink CAC algorithm switchDownlink CAC algorithm switchNodeB Credit CACCAC algorithm switch : CacSwitchCell CAC algorithm switch: CRD_ADCTRLHSDPA user number CACCAC algorithm switch :HSDPA_UU_ADCTRLHSUPA user number CACCAC algorithm switch: HSUPA_UU_ADCTRLAlgorithm Switch of CACExcept the mandatory code and Iub resource admission control, the admission control basedon power and NodeB credit ,HSDPA User Number can be disabled through the LMT command:Power CAC can be switched off by ADD CELLALGOSWITCH / MOD CELLALGOSWITCHUplink CAC algorithm switch (NBMULCACALGOSELSWITCH ) specifies the algorithm usedfor power admission in the uplink.Downlink CAC algorithm switch (NBMDLCACALGOSELSWITCH) specifies the algorithmused for power admission in the downlink.NodeB Credit CAC can be switched off by SET CACALGOSWITCH or ADDCELLALGOSWITCH / MOD CELLALGOSWITCHCAC algorithm switch (CacSwitch) specifies the NodeB level credit CAC algorithmCell CAC algorithm switch (CRD_ADCTRL) specifies the Cell level credit CAC algorithmHSDPA user number CAC switched off by ADD CELLALGOSWITCH / MODCELLALGOSWITCHHSDPA_UU_ADCTRL specifies whether to enable or disable the HSDPA admission controlalgorithm.HSUPA user number CAC switched off by ADD CELLALGOSWITCH / MODCELLALGOSWITCHHSUPA_UU_ADCTRL specifies whether to enable or disable the HSUPA admission controlalgorithm
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Code ResourceCode Resource CAC functions in:RRC connection setupHandoverR99 services RAB setupNote: RRC connection setup and Handover have higher priorityWhen a new service attempts to access the network, code resource admission ismandatory.1. For RRC connection setup requests, the code resource admission is successful if thecurrent remaining code resource is enough for the RRC connection.2. For handover services, the code resource admission is successful if the currentremaining code resource is enough for the service.3. For other R99 services, the RNC has to ensure that the remaining code does notexceed the configurable threshold after admission of the new service.4. For HSDPA services, the reserved codes are shared by all HSDPA services. Therefore,the code resource admission is not needed.So the RRC connection setup and Handover has higher priority to access a cell
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Power ResourceUL and DL Power Resource CAC functions in:R99 cellRRC connection setupR99 RAB setupHandoverHSPA cellRRC connectionR99 RAB setupHSPA RAB setupHandoverNote: RRC connection setup and Handover have higher priorityThe UL CAC and DL CAC are independent .The basic principle of Power CAC is: RNC predict the cell power load after the access. Ifthe load will be higher than a threshold, the admission is failed.So, by setting different threshold for different access, we can realize different priorities.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Power CAC AlgorithmsAlgorithm 1: based on UL/DL load measurement and loadprediction (RTWP and TCP)Algorithm 2: based on Equivalent Number of User (ENU)Algorithm 3: loose call admission control algorithmHuawei provide 3 Power CAC AlgorithmsAlgorithm 1: power resource admission decision based on power or interference.Depending on the current cell load (uplink load factor and downlink transmitted carrier power)and the access request, the RNC determines whether the cell load will exceed the thresholdupon admitting a new call. If yes, the RNC rejects the request. If not, the RNC accepts therequest.Algorithm 2: power resource admission decision based on the number of equivalentusers.Based on Huawei testing and experience, The 12.2 kbit/s AMR traffic is used tocalculate the Equivalent Number of Users (ENU) of all other services in UL and DL. The12.2 kbit/s AMR traffics ENU is assumed to be 1. Depending on the current number ofequivalent users and the access request in UL and DL, the RNC determines whether thenumber of equivalent users will exceed the threshold upon admitting a new call. If yes, theRNC rejects the request. If not, the RNC accepts the request.Algorithm 3: power resource admission decision based on power or interference, but withthe estimated load increment always set to 0.Depending on the current cell load (uplink loadfactor and downlink TCP) and the access request, the RNC determines whether the cellload will exceed the threshold, with the estimated load increment set to 0. If yes, the RNCrejects the request. If not, the RNC accepts the request.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Basic principle of Uplink CAC Algorithm 1Get current RTWP, and calculate thecurrent load factorAdmission requestGet the traffic characteristic, andestimate the increment of load factorCalculate the predicted load factoradmitted rejectedEnd of UL CACY NSmaller thanthe threshold?RTWPPNUL −= 1ηηΔCCHULpredictedUL ηηηη +Δ+=_Pn is uplink receive background noise.The procedure for uplink power resource decision is as follows:1. The RNC obtains the uplink RTWP of the cell, and calculate the current uplink loadfactor.2. The RNC calculates the uplink load increment ΔηUL based on the service request.3. The RNC uses the formula ηUL,predicted=ηUL + ΔηUL to forecast the uplink loadfactor.4. By comparing the forecasted uplink load factor ηUL,predicted with the correspondingthreshold ,the RNC decides whether to accept the access request or not.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Basic principle of Downlink CAC Algorithm1The procedure for downlink power resource decision is as follows:1. The RNC obtains the cell downlink TCP, and calculates the downlink load factor bymultiplying the maximum downlink transmit power by this TCP.2. The RNC calculates the downlink load increment ΔP based on the service request andthe current load.3. The RNC forecasts the downlink load factor.4. By comparing the downlink load factor with the corresponding threshold (DL thresholdof Conv AMR service, DL threshold of Conv non_AMR service, DL threshold of otherservices, DL Handover access threshold), the RNC decides whether to accept theaccess request or not.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Basic principle of CAC Algorithm 2Get current total ENUAdmission requestGet the traffic characteristic, andestimate the increment of ENUCalculate the predicted ENUadmitted rejectedEnd of UL/DL CACY NSmaller thanthe threshold?∑==Niitotal ENUNENU1)(newENUnewtotaltotal ENUNENUNENU +=+ )()1(max/)1( ENUNENUENULoad total +=The procedure for ENU resource decision is as follows:1. The RNC obtains the total ENU of all exist users ENUtotal.2. The RNC get the ENU of the new incoming user ENUnew.3. The RNC forecast the ENU load.4. By comparing the forecasted ENU load with the corresponding threshold (the samethreshold as power resource), the RNC decides whether to accept the access requestor not.The ENUmax can be set by LMT, the ENUnew and ENUi is determined by Huaweialgorithm, there is an example in next slide.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Power CAC for RRC connection SetupFor the RRC connection request is, tolerance principles areapplied :Emergency call, Detach , RegistrationDirect AdmissionRRC connection request for other reasonsUL/ DL OLC Trigger threshold AdmissionTo ensure that the RRC connection request is not denied by mistake, tolerance principlesare applied.The admission decision is made for the following reasons of the RRC connection request:1. For the RRC connection request for the reasons of emergency call, detach orregistration, direct admission is used ,that is no limitation.2. For the RRC connection request for other reasons, UL/DL OLC Triggerthreshold is used for admission. By default, the OLC trigger threshold isrelatively high (DL/UL 95%), which make the RRC connections are easily setup.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL Power CAC for R99 Cell (Algorithm1)For R99 DCH RAB Setup, The RNC uses the following formulato predict the uplink load factor :Where theBy comparing the predicted uplink load factor ηUL,predicted with thecorresponding threshold ,the RNC decides whether to accept theaccess request or notCCHULULULpredictedUL −+Δ+= ηηηη _RTWPPNUL −=1ηThe threshold for Conv AMR service , Conv non_AMR service , Other R99 services ,Handover are set independently, which provide different priorities.Normally, Other R99 services < Conv non_AMR service services < Conv AMRservice < HandoverThe uplink load increment ΔηUL is determined by :1. The Eb/No of the new incoming call2. The uplink load increment is proportional to the value of Eb/No.3. UL neighbor interference factor4. Active Factor of the new incoming call
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL Power CAC for R99 Cell (Algorithm1)For R99 DCH RAB Setup, The RNC uses the following formula topredict the downlink load factor :Where theBy comparing the predicted downlink load factor ηDL,predicted withthe corresponding threshold ,the RNC decides whether to acceptthe access request or notCCHDLDLDLpredictedDL −+Δ+= ηηηη _maxPTCPDL =ηmaxPDLDLηηΔ=ΔThe threshold for Conv AMR service , Conv non_AMR service , Other R99 services ,Handover are set independently, which provide different priorities.Normally, Other R99 services < Conv non_AMR service services < Conv AMR service <HandoverThe downlink load increment ΔηDL is determined by :1. The Eb/No of the new incoming call2. Non-orthogonality factor3. Current transmission carrier power4. Active Factor of the new incoming call
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL Power CAC for HSPA Cell (Algorithm1)The power increment of an HSUPA service is related to Ec/No,GBR requirement, neighboring interference factor, active factor ofthe service. The formula of UL power CAC for HSUPA is similar tothat for R99After RSEPS measurement is introduced, the UL RTWP is dividedinto two parts:Controllable partThe UL interference generated by E-DCH scheduling services belong tothe controllable partUncontrollable partRSEPS: Received scheduled E-DCH power share
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL Power CAC for HSPA Cell (Algorithm1)E-DCH scheduling service consists of following two types:TypeA: all UEs for which this cell is the serving E-DCH cellThe uplink load generated by TypeA E-DCH scheduling service is defined as follows:TypeB: all UEs for which this cell isNOT the serving EDCH-cellThe uplink load generated byTypeB E-DCH scheduling serviceis defined by ηUL,EDCH,f,which is fixed to zeroThe Uplink uncontrollable loadIs defined as follows:RTWPRSEPSSEDCHUL =− ,ηfEDCHULsEDCHULULctrlnonUL ,,,,, ηηηη −−=−
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL Power CAC for HSPA Cell (Algorithm1)UL Power CAC for HSUPA Scheduling Services and HSUPA Non-Scheduling ServicesRNC admits HSUPA scheduling service in either of the following casesFormula 1,2 or 3 is fulfilledFormula 4 is fulfilledRNC admits HSUPA Non-scheduling service in either of the following casesFormula 1,2 or 3 is fulfilledFormula 4 and 5 are fulfilledThdL is the Low priority HSUPA user PBR threshold of the current cellThdE is the Equal priority HSUPA user PBR threshold of the current cellThdGE is the High priority HSUPA user PBR threshold of the current cellηHS-DPCCH is the value of the UL HS-DPCCH reserve factor parameter, which defines the factor ofUL HS-DPCCH resource reservedηthd is the cell UL admission threshold for specific type of service, that is UL threshold of ConvAMR service, UL threshold of Conv non_AMR service, UL threshold of other services or ULhandover access service threshold
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL Power CAC for HSPA Cell (Algorithm1)UL Power CAC for R99 service in HSPA cellUncontollable interference must be kept within a givenrange. The purpose is to ensure the stability of system andto prevent non-scheduling services and DCH servicesfrom seizing the resources of HSUPA servicesRNC admits R99 services if formula 1 and 2 are fulfilledthdDPCCHHScchULULctrlnonUL ηηηηη <++Δ+ −− ,,totalthdDPCCHHScchULULUL −− <++Δ+ ηηηηη .,ηthd-total is the UL total power threshold of the current cellηthd is the cell UL admission threshold for specific type of service, that is UL threshold of ConvAMR service, UL threshold of Conv non_AMR service, UL threshold of other services or ULhandover access service threshold
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL Power CAC for HSPA Cell (Algorithm1)DL Power incremental estimation for DCH RAB in HSPAcell is similar to the DCH RAB in R99 cellDL Power incremental estimation for HSDPA RAB ΔPDL ismade based on GBR, Ec/No, Non-orthogonality factor
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL Power CAC for HSPA Cell (Algorithm1)DL power CAC for R99 service in HSPA cellRNC admits R99 service (i.e. DCH RAB) in either of thefollowing situations:Formula 1 and 2 are fulfilledFormula 1 and 3 are fulfilledPnon-hspa is the current non-HSDPA powerPcch-res is the power reserved for the common channelPmax is the cell maximum transmit powerThdnon-hspa-cac is the cell DL admission threshold for different types of service, that is DLthreshold for Conv AMR service, DL threshold for Conv non-AMR service, DL threshold forother service or DL handover access thresholdPtotal is the current downlink transmitted carrier powerThdtotal-cac is the threshold of cell DL total power. It is defined by the DL total power thresholdparameterGBP is power requirement for GBRPhsupa-res is the power reserved for HSUPA downlink control channels (E-AGCH/E-RGCH/E-HICH)Pmax-hspa is the maximum available power for HSPA. Its value is associated with the HSDPApower allocation mode.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL Power CAC for HSPA Cell (Algorithm1)DL power CAC for HSDPA RAB in HSPA cellRNC admits the HSDPA streaming service in any of the following situations:Formula 1 is fulfilledFormulas 3 and 4 are fulfilledFormulas 3 and 5 are fulfilledRNC admits the HSDPA BE service in any of the following situations:Formula 2 is fulfilledFormulas 3 and 4 are fulfilledFormulas 3 and 5 are fulfilledPBRstrm is the provided bit rate of all existing streaming servicesThdhsdap-str is the admission threshold for streaming PBR decision. It is defined by the Hsdpastreaming PBR threshold parameterPBRbe is the provided bit rate of all existing BE servicesThdhsdap-be is the admission threshold for BE PBR decision. It is defined by the Hsdpa best effortPBR threshold parameterGBR is the power requirement for GBRPhsupa-res is the power reserved for HSUPA downlink control channels (E-AGCH/E-RGCH/E-HICH)Pmax-hspa is the maximum available power for HSPA. Its value is associated with the HSDPApower allocation mode.Ptotal is the current downlink transmitted carrier powerPmax is the cell maximum transmitted powerThdtotal-cac is the threshold of cell DL total power, which is defined by the DL total powerthreshold parameterPcch-res is the power reserved for the common channelsPnon-hspa is the current non-HSDPA power
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL Power CAC for HSPA Cell (Algorithm1)DL power CAC for HSUPA control channels in HSPA cellThe power of downlink control channels (E-AGCH/E-RGCH/E-HICH) are reserved by DL HSUPA reserved factor. Therefore,the power admission for these channels is NOT needed
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Power CAC for Algorithm2For R99 and HSDPA RAB, The RNC uses the following formulato predict the uplink load factor :(ENUtotal + ENUnew) / ENUmaxBy comparing the forecasted ENU load with the correspondingthreshold ,the RNC decides whether to accept the access requestor notENUtotal is the total ENU of all existing users.ENUnew is ENU of the new incoming user .ENUmax is the configured maximum ENU (UL total equivalent user number or DL totalnonhsdpa equivalent user number) .The threshold for Algorithm2 are the same with Algorithm1,for Conv AMR service ,Conv non_AMR service , Other R99 services , Handover , HSDPA are set independently:DL total power thresholdHSDPADL threshold of Conv AMR serviceDL threshold of Conv non_AMR serviceDL threshold of other servicesDL Handover access thresholdDL DCHUL threshold of Conv AMR serviceUL threshold of Conv non_AMR serviceUL threshold of other servicesUL Handover access thresholdUL DCH/HSUPAAdmission ThresholdService Type
    • Typically ENU (equivalent number of users) for different services (with activity factor to be100%)DL total power thresholdHSDPADL threshold of Conv AMR serviceDL threshold of Conv non_AMR serviceDL threshold of other servicesDL Handover access thresholdDL DCHUL threshold of Conv AMR serviceUL threshold of Conv non_AMR serviceUL threshold of other servicesUL Handover access thresholdUL DCH/HSUPAAdmission ThresholdService Type
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL threshold of Conv AMR serviceParameter ID: UlNonCtrlThdForAMRThe default value of this parameter is 75%UL threshold of Conv non_AMR serviceParameter ID: UlNonCtrlThdForNonAMRThe default value of this parameter is 75%Key parametersUL threshold of Conv AMR serviceParameter ID: UlNonCtrlThdForAMRValue range: 0 to 100 %Content: The uplink threshold for the AMR conversational service is used for the uplinkadmission of AMR conversational service users. The threshold is shared by algorithm 1,algorithm 2 and algorithm 3.The default value of this parameter is 75%Set this parameter through ADD CELLCAC / MOD CELLCACUL threshold of Conv non_AMR serviceParameter ID: UlNonCtrlThdForNonAMRValue range: 0 to 100 %Content: The downlink threshold for the AMR conversational service is used for thedownlink admission of AMR conversational service users. The threshold is shared byalgorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 75%Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL threshold of other servicesParameter ID: UlNonCtrlThdForOtherThe default value of this parameter is 60%UL Handover access thresholdParameter ID: UlNonCtrlThdForHoThe default value of this parameter is 80%Key parametersUL threshold of other servicesParameter ID: UlNonCtrlThdForOtherValue range: 0 to 100 %Content: This parameter is the uplink threshold for services other than theconversational service. It is used for uplink admission of other services. The threshold isshared by algorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 60%Set this parameter through ADD CELLCAC / MOD CELLCACUL Handover access thresholdParameter ID: UlNonCtrlThdForHoValue range: 0 to 100 %Content: The uplink handover threshold is used for uplink admission of handover users.The parameter is useful only to uplink inter-frequency handovers. Do not make theadmission decision in the uplink soft handover. The threshold is shared by algorithm 1,algorithm 2 and algorithm 3.The default value of this parameter is 80%Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL threshold of Conv AMR serviceParameter ID: DLCONVAMRTHDThe default value of this parameter is 80%DL threshold of Conv non_AMR serviceParameter ID: DLCONVNAMRTHDThe default value of this parameter is 80%Key parametersDL threshold of Conv AMR serviceParameter ID: DLCONVAMRTHDValue range: 0 to 100 %Content: The downlink threshold for the AMR conversational service is used for thedownlink admission of AMR conversational service users. The threshold is shared byalgorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 80%Set this parameter through ADD CELLCAC / MOD CELLCACDL threshold of Conv non_AMR serviceParameter ID: DLCONVNAMRTHDValue range: 0 to 100 %Content: The downlink threshold for the non-AMR conversational service is used for thedownlink admission of non-AMR conversational service users. The threshold is sharedby algorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 80%Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL threshold of other servicesParameter ID: DLOTHERTHDThe default value of this parameter is 75%DL Handover access thresholdParameter ID: DLHOTHDThe default value of this parameter is 85%Key parametersDL threshold of other servicesParameter ID: DLOTHERTHDValue range: 0 to 100 %Content: This parameter is the downlink threshold for services other than theconversational service. It is used for downlink admission of users of other services. Thethreshold is shared by algorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 75%Set this parameter through ADD CELLCAC/MOD CELLCACDL Handover access thresholdParameter ID: DLHOTHDValue range: 0 to 100 %Content: The downlink handover threshold is used for downlink admission of handoverusers. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3.The default value of this parameter is 85%Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL total power thresholdParameter ID: DLCELLTOTALTHDThe default value of this parameter is 90%Hsdpa streaming PBR thresholdParameter ID: HSDPASTRMPBRTHDThe default value of this parameter is 70%Hsdpa best effort PBR thresholdParameter ID: HSDPABEPBRTHDThe default value of this parameter is 70%Key parametersDL total power thresholdParameter ID: DLCELLTOTALTHDValue range: 0 to 100 %Content: This parameter specifies the total downlink power threshold of the cell.The default value of this parameter is 90%Set this parameter through ADD CELLCAC / MOD CELLCACHsdpa streaming PBR thresholdParameter ID: HSDPASTRMPBRTHDValue range: 0 to 100 %Content: This parameter specifies the average throughput admission threshold of theHSDPA streaming traffic.The default value of this parameter is 70%Set this parameter through ADD CELLCAC / MOD CELLCACHsdpa streaming PBR thresholdParameter ID: : HSDPABEPBRTHDValue range: 0 to 100 %Content: This parameter specifies the average throughput admission threshold of theHSDPA best effort traffic.The default value of this parameter is 70%Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL total equivalent user numberParameter ID: ULTOTALEQUSERNUMThe default value of this parameter is 80DL total equivalent user numberParameter ID: DLTOTALEQUSERNUMThe default value of this parameter is 80Key parametersUL total equivalent user numberParameter ID: ULTOTALEQUSERNUMValue range: 1 to 200Content: When algorithm 2 is used, this parameter defines the total equivalent numberof users corresponding to the 100% uplink load.The default value of this parameter is 80Set this parameter through ADD CELLCAC/MOD CELLCACDL total equivalent user numberParameter ID: DLTOTALEQUSERNUMValue range: 1 to 200Content: When algorithm 2 is used, this parameter defines the total equivalent numberof users corresponding to the 100% downlink load.The default value of this parameter is 80Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on NodeB Credit ResourceWhen a new service accesses the network, NodeB creditresource admission is optionalThe principles of NodeB credit admission control are similarto those of power resource admission control, that is, tocheck in the local cell whether the remaining credit cansupport the requesting servicesCE stands for NodeB credit on RNC side and for Channel Element on NodeB side. It isused to measure the channel demodulation capability of the NodeBsThe resource of one 12.2kbps voice service, including 3.4kbps signaling on the DCCH,consumed in baseband is defined as one CE. If there is 3.4kbps signaling on the DCCH,but no voice channel, one CE is consumed.The credit resource are divided into severalresource pools. Each resource pool is shared by a local cell.According to the common and dedicated channels capacity consumption laws, as well asthe addition, removal, and reconfiguration of the common and dedicated channels, theControlling RNC (CRNC) debits the amount of the credit resource consumed from orcredits the amount to the Capacity Credit of the local cell group (and local cell , if any)based on the spreading factor.the UL Capacity Credit and DL Capacity Credit are separate, so the CAC is performed inthe UL and DL, respectively.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on NodeB Credit ResourceFor DCH service, MBR is used to calculate the NodeBCredit based on spreading factor :The total NodeB Credit Resource of a local cell is depend onthe configuration.204UL 384 kbit/s PS88DL108UL 128 kbit/s PS416DL616UL 64 kbit/s PS232DL332UL 32 kbps PS164DL616UL 64 kbit/s VP232DL264UL 12.2 kbit/s AMR1128DL264UL 13.6 kbit/s SRB1128DL2256UL 3.4 kbit/s SRB1256DLTypical Traffic ClassCorresponding Credits ConsumedSpreadingFactorDirection
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on NodeB Credit ResourceFor HSUPA service, the rate used to calculate thespreading factor is MBR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on NodeB Credit ResourceWhen a new service tries to access the network, the creditresource admission CAC functions in :RRC connection setupHandover serviceThe other servicesFor an RRC connection setup request, the credit resource admission is successful if the currentremaining credit resource is sufficient for the RRC connection.For a handover service, the credit resource admission is successful if the current remaining creditresource is sufficient for the service.For other services, the RNC has to ensure that the remaining credit does not exceed theconfigurable thresholds after admission of the new services.There is no capacity consumption law for HS-DSCH in 3GPP TS 25.433, so certain credits arereserved for HSDPA RAB, and credit admission for HSDPA is not needed.UL Capacity Credit and DL Capacity Credit are separate, the credit resource admission isimplemented in the UL and DL, respectively.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Ul HandOver Credit Reserved SFParameter ID: UlHoCeResvSfThe default value of this parameter is SF16Dl HandOver Credit and Code Reserved SFParameter ID: DlHoCeCodeResvSfThe default value of this parameter is SF32Key parametersUl HandOver Credit Reserved SFParameter ID: UlHoCeResvSfValue range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFFContent: The spreading factor specified by this parameter is used to define the uplinkcredit resource reserved for handover services.SFOFF means that none of resources are reserved for handover services. If theremaining uplink resource cannot fulfill the requirement for the reserved resource afterthe admission of a new service, the service is rejected.The default value of this parameter is SF16Set this parameter through ADD CELLCAC / MOD CELLCACDl HandOver Credit and Code Reserved SFParameter ID: DlHoCeCodeResvSfValue range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFFContent: The spreading factor specified by this parameter is used to define the downlinkcredit and channelized code resources reserved for handover services.SFOFF means that none of the resources is reserved for handover. If the remainingdownlink resource cannot fulfill the requirement for the reserved resource after theaccess of a new service, the service is rejected.The default value of this parameter is SF32Set this parameter through ADD CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Iub Interface ResourceThe CAC of the Iub transmission resources is similarAdmission Control is used to determine whether the Iubresources are enough to accept a new access requestIt functions in:RRC connection setup and Services RAB setupHandoverA user accessing the network from a path should go through the admission of the path,resource group, and physical port in turn. The user that passes all the admission can besuccessfully admitted by the transport layer.Path means AAL2 PATH, IP PATHThe physical ports correspond to IMA, UNI, FRAATM, NCOPT, ETHER, PPP, and MLPPP.The priority of the 2 types of access follows : Handover >RRC connection setup andServices RAB setup
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Iub Interface ResourceIub OverbookingThe Iub overbooking feature considers the statistic multiplexingof service activities and multiple usersAdmit more users, increases the resource utilization on the Iubinterface.The Iub overbooking feature considers the statistic multiplexing of service activities andmultiple users. Through the admission of more users, Iub overbooking increases theresource utilization on the Iub interface.If the RNC allocates the maximum bandwidth to the subscriber when a service isestablished, a large proportion of the Iub transmission bandwidth is unused. For example,downloading a 50 KB page takes only about one second, but reading this page needsdozens of seconds. Thus, over 90% of the Iub transmission bandwidth is not used.To save the Iub transmission bandwidth for operator use, Huawei provides the Iuboverbooking function, which applies an admission control mechanism to access theservice.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Iub Interface ResourceIub OverbookingCS voice servicesService rate:12.2 kbit/sSIDPS interactive and background servicesDownload timeReading timeThe UMTS supports four traffic classes: conversational, streaming, interactive, andbackground.The transmission rate varies with the traffic class as follows:For Circuit Switched (CS) conversational services, the channel transmits voice signals ata certain rate (for example, 12.2 kbit/s) during a conversation and only transmits SilenceDescriptors (SIDs) at intervals when there is no conversation.For Packet Switched (PS) interactive and background services, such as web browsing,there is data transmitted during data downloading. After a web page has beendownloaded, and when the user is reading the page, however, there is very little data totransfer.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Iub Interface ResourceIub OverbookingCS voice servicesActivity FactorPS interactive and background servicesGBRMMLSET DEFAULTFACTORTABLESET USERGBRSET CORRMALGOSWITCH (IUB_OVERBOOKING_SWITCH)ADD AAL2PATHADD IPPATHUse SET DEFAULTFACTORTABLE to set a default of Activity Factor table for all theservices.Use SET USERGBR to set GBR for BE servicesUse SET CORRMALGOSWITCH (IUB_OVERBOOKING_SWITCH) to define the switchof Iub overbooking
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.CAC Based on Number of HSPA UsersHSPA user number can be limited in:Cell levelmaximum number of HSPA users in a cellNodeB levelMaximum number of HSPA users in all the cells configured inone NodeBWhen the HSDPA_UU_ADCTRL is on, the HSDPA services have to undergo HSDPAuser number admission decision.When a new HSDPA service attempts to access the network, it is admitted if the numberof HSDPA users in the cell and that in the NodeB do not exceed the associatedthresholdsWhen the HSUPA_UU_ADCTRL is on, the HSUPA services have to undergo HSUPAuser number admission decision.When a new HSUPA service attempts to access the network, it is admitted if the numberof HSUPA users in the cell and that in the NodeB do not exceed the associatedthresholds
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.HSDPA_UU_ADCTRLParameter ID: HSDPA_UU_ADCTRLMaximum HSDPA user numberParameter ID: MaxHSDSCHUserNumThe default value of this parameter is 64HSDPA_UU_ADCTRLParameter ID: HSUPA_UU_ADCTRLMaximum HSUPA user numberParameter ID: MaxHsupaUserNumThe default value of this parameter is 20Key parametersMaximum HSDPA user numberParameter ID: MaxHSDSCHUserNumValue range: 0 to 100Content: This parameter specifies the maximum number of HSDPA users in a cell.The default value of this parameter is 64Set this parameter through ADD CELLCAC/MOD CELLCACHSDPA_UU_ADCTRLParameter ID: HSDPA_UU_ADCTRLValue range: 0 ,1Content: This parameter specifies whether to enable or disable the HSDPA admission control algorithm.Set this parameter through ADD CELLALGOSWITCH / LST CELLALGOSWITCH/MODCELLALGOSWITCHHSUPA_UU_ADCTRLParameter ID: HSDPA_UU_ADCTRLValue range: 0 ,1Content: This parameter specifies whether to enable or disable the HSDPA admission control algorithm.Set this parameter through ADD CELLALGOSWITCH / LST CELLALGOSWITCH/MODCELLALGOSWITCHMaximum HSUPA user numberParameter ID: MaxHsupaUserNumValue range: 0 to 100Content: This parameter specifies the maximum number of HSDPA users in a cell.The default value of this parameter is 20Content: This parameter specifies the maximum number of HSUPA users in a cell.Set this parameter through ADD CELLCAC / LST CELLCAC / MOD CELLCAC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Why we need IAC?The disadvantage of CACFor PS NRT (Non-Real Time) services, CAC is not flexibleNo consideration about the priority of different usersNo consideration about Directed Retry after CAC rejection“Intelligent” means the algorithm can increase admissionsuccessful rateCAC limits the setup of RRC and RAB . When the cell is overloaded , the CAC will causeaccess failure.In order to improve the access success rate the Intelligent Access Control (IAC) algorithm isused to improve the access success rate. The IAC procedure includes rate negotiation,Call Admission Control (CAC), preemption, queuing, and Directed Retry Decision (DRD).
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC OverviewThe access procedure (include the IAC)As shown in the Figure, the procedure for the UE access includes the procedures for RRCconnection setup and RAB setup. The success in the RRC connection setup is one of theprerequisites for the RAB setup.During the RRC connection processing, if resource admission fails, DRD and redirection apply.During the RAB processing, the RNC performs the following steps:• Performs RAB DRD to select a suitable cell to access, for service steering or load balancing.• Performs rate negotiation according to the service requested by the UE.• Performs cell resource admission decision. If the admission is passed, UE access is granted.Otherwise, the RNC performs the next step.• Selects a suitable cell, according to the RAB DRD algorithm, from the cells where no admissionattempt has been made, and then goes to rate negotiation and cell resource admission again. Ifall DRD admission attempts to the cells fail, go to the next step.• Makes a preemption attempt. If the preemption is successful, UE access is granted. If thepreemption fails or is not supported, the RNC performs the next step, queuing.• Makes a queuing attempt. If the queuing is successful, UE access is granted. If the queuing failsor is not supported, the RNC Rejects UE access.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC - RRC Connection ProcessingWhen a new service accesses the network, an RRC connection must be set up first. If theRRC connection request is denied, DRD is performed. If DRD also fails, RRCredirection is performed to direct the UE to an inter-frequency or inter-RAT cellthrough cell reselection.After the RNC receives the RRC CONNECTION REQUEST message, the CAC algorithmdecides whether an RRC connection can be set up between the UE and the currentcell.If the RRC connection can be set up between the UE and the current cell, the RNC sendsan RRC CONNECTION SETUP message to the UE. If the RRC connection cannotbe set up between the UE and the current cell, the RNC takes the followingactions:RRC DRD :If the DRD_SWITCH is set to 0, the RRC DRD fails, and RRC redirection is performed.Else, the RNC performs the following steps:1. The RNC selects inter-frequency neighboring cells of the current cell. Theseneighboring cells are suitable for blind handovers.2. The RNC generates a list of candidate DRD-supportive inter-frequency cells. Thequality of the candidate cell meets the requirements of inter-frequency DRD:(CPICH_Ec/No)RACH > DRD_Ec/No nbcellwhere(CPICH_Ec/No)RACH is the cached CPICH Ec/N0 value included in the RACHmeasurement report.DRD_Ec/No nbcell is the DRD Ec/N0 Threshold set for the inter-frequencyneighboring cell.
    • 3. RNC selects a target cell from the candidate cells for UE access. If the candidate cell list containsmore than one cell, the UE tries a cell randomly.1. If the admission is successful, the RNC initiates an RRC DRD procedure.2. If the admission to a cell fails, the UE tries admission to another cell in the candidate celllist. If all the admission attempts fail, the RNC makes an RRC redirection decision.4. If the candidate cell list does not contain any cell, the RRC DRD fails. The RNC performs the nextstep, that is, RRC redirection.5. RRC redirection, the RNC performs the following steps:1. The RNC selects all inter-frequency cells of the local cell.2. The RNC selects candidate cells. That is, exclude the cells to which inter-frequency RRCDRD attempts have been made from the cells selected in the previous step.3. If more than one candidate cell is available, the RNC selects a cell randomly and redirectsthe UE to the cell.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Key parametersRRC redirect switchParameter ID: RrcRedictSwitchThe default value of this parameter isOnly_To_Inter_FrequencyDRD Ec/N0 thresholdParameter ID: DRDEcN0ThreshholdThe default value of this parameter is -18(-9 dB)RRC redirect switchParameter ID: RrcRedictSwitchValue range: OFF, Only_To_Inter_Frequency, Allowed_To_Inter_RATContent: This parameter specifies the RRC redirection strategy.The default value of this parameter is Only_To_Inter_FrequencySet this parameter through SET DRDDRD Ec/N0 thresholdParameter ID: DRDEcN0ThreshholdValue range: –24 to 0Content: If the measured Ec/N0 value of the neighbor cell is less than thisparameter, this neighboring cell cannot be selected to be the candidate DRDcell.The default value of this parameter is -18(-9 dB)Set this parameter through ADD INTERFREQNCELL
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – PS Rate NegotiationPS Service Rate Negotiation Includes:Maximum expected rate negotiationInitial rate negotiationTarget rate negotiationRate negotiation includes the maximum expected rate negotiation, initial rate negotiation, and target rate negotiation.When setting up, modifying, or admitting a PS service (conversational, streaming, interactive, or background service)the RNC and the CN negotiate the rate according to the UE capability to obtain the maximum expected rate whileensuring a proper QoS.For a non-real-time service in the PS domain, the RNC selects an initial rate to allocate bandwidth for the servicewhen Setup or UE state transits from CELL_FACH to CELL_DCH based on cell code and credit resourceThe Initial rate selection is affected by 2 algorithm switches: RAB Downsizing Switch, DCCC SwitchFor DCH For HSUPAFor a non-real-time service in the PS domain, if cell resource admission fails, the RNC chooses a target rate toallocate bandwidth for the service based on cell resource in Service setup or Soft handover
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Key parametersRAB_Downsizing_SwitchParameter ID: RAB_DOWNSIZING_SWITCHThe default value of this parameter is 1 (on)UL/DL BE traffic Initial bit rateParameter ID:ULBETRAFFINITBITRATE / DLBETRAFFINITBITRATEThe default value of this parameter is D64 (64k)RAB_Downsizing_SwitchParameter ID: RAB_DOWNSIZING_SWITCHValue range: (0,1)Content: This parameter specifies whether to support the RAB downsizing function.The default value of this parameter is 1 (on)When this parameter is set to 1, the RAB downsizing function is applied todetermine the initial bit rate based on cell resources (code and credit). .Set this parameter through SET CORRMALGOSWITCHUL/DL BE traffic Initial bit rateParameter ID: ULBETRAFFINITBITRATE / DLBETRAFFINITBITRATEValue range: D8, D16, D32, D64, D128, D144, D256, D384, D768, D1024, D1536,D1800, D2048 kContent: This parameter defines the uplink initial access rate of background andinteractive services in the PS domain.The default value of this parameter is D64 (64k)Set this parameter through SET FRC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – RAB Directed Retry DecisionRAB Directed Retry Decision (DRD) is used to select asuitable cell for the UE to try an accessInter-frequency DRDService SteeringLoad BalancingInter-RAT DRDThrough the RAB DRD procedure, the RNC selects a suitable cell for RAB processingduring access control. RAB DRD is of two types: inter-frequency DRD and inter-RATDRD. For inter-frequency DRD, the service steering and load balancing algorithms areavailable.After receiving a RANAP RAB ASSIGNMENT REQUEST, the RNC initiates an RABDRD procedure to select a suitable cell for RAB processing during access control.The RNC performs inter-frequency DRD firstly. If all admission attempts of inter-frequency DRD fail, the RNC performs an inter-RAT DRD. If all admission attempts ofinter-RAT DRD fail, the RNC selects a suitable cell to perform preemption andqueuing .Relation Between Service Steering DRD and Load Balancing DRDWhen both service steering DRD and load balancing DRD are enabled, the generalprinciples of inter-frequency DRD are as follows:• Service steering DRD takes precedence over load balancing DRD. That is,preferably take service priorities into consideration.• To services of the same service priority, load balancing applies.
    • IAC – RAB Directed Retry DecisionRAB Directed Retry SwitchsDRD is applicable to RAB setup only when thisswitch is on.RAB_SETUP_DRD_SWITCHRAB setupDRD is applicable to traffic-volume-basedDCCC procedure or UE state transition, onlywhen this switch is on.RAB_DCCC_DRD_SWITCHDCCCDRD is applicable to RAB modification onlywhen this switch is on.RAB_MODIFY_DRD_SWITCHRAB modificationDRD is applicable to HSUPA services onlywhen this switch is on.HSUPA_DRD_SWITCHHSUPA serviceDRD is applicable to HSDPA services onlywhen this switch is on.HSDPA_DRD_SWITCHHSDPA serviceDRD is applicable to combined services onlywhen this switch is on.COMB_SERV_DRD_SWITCHCombinedservicesThis is the primary DRD algorithm switch. Thesecondary DRD switches are valid only whenthis switch is on.DRD_SWITCHDRD switchDescriptionSwitchScenarioDRD algorithm switchParameter ID: DRDSWITCHThe default value of this parameter is offSet this parameter through SET CORRMALGOSWITCH
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD for Service SteeringDRD for Service Steering is based on Service priorities ofcells ,include:– R99 RT services priority– R99 NRT services priority– HSPA services priority– Other services priorityCalled Service priority groupIf the UE requests a service in an area covered by multiple frequencies, the RNC selectsthe cell with the highest service priority for UE access, based on the service type ofRAB and the definitions of service priorities in the cells.Cell service priorities help achieve traffic absorption in a hierarchical way.The priorities of specific service types in cells are configurable. If a cell does not support aservice type, the priority of this service type is set to 0 in this cell.The service priorities in each cell is called Service priority group , which is identified bythe Service priority group Identity parameter.Service priority groups are configured on the LMT. In each group, priorities of R99 RTservices, R99 NRT services, HSPA services, and other services are defined.When selecting a target cell for RAB processing, the RNC check the service type firstly ,then, selects a cell with a high priority for the service, that is, a cell that has a smallvalue of service priority.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD for Service SteeringAn example of service priority group0021201121Servicepriority ofother serviceService priorityof HSPAserviceService priorityof R99 NRTserviceService priorityof R99 RTserviceServicepriority groupIdentityCell A and cell B are of different frequencies.Assume that the service priority groups given in the table are defined on an RNC, 2groups of service priorities are defined.Then ,Cell A is configured with service priority group 1. Cell B is configured with servicepriority group 2If UE requests a R99 RT service in cell A ,Cell B has a higher service priority of the R99RT service than cell A. If the UE requests an RT service in cell A, preferably, the RNCselects cell B for the UE to access.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD procedure for Service SteeringThe procedure for the service steering DRD is as follows:1、The RNC determines candidate cells to which blind handovers can be performed and sorts thecandidate cells into a descending order according to service priority.A candidate cell must meet the following conditions:• The frequency of the candidate cell is within the band supported by the UE.• The quality of the candidate cell meets the Ec/No requirements of inter-frequency DRD (DRDEc/N0 Threshold )• The candidate cell supports the requested service.2、The RNC selects a target cell from the candidate cells in order of service priority for UE access.3、The CAC algorithm makes an admission decision based on the status of the target cell.• If the admission attempt is successful, the RNC accepts the service request.• If the admission attempt fails, the RNC removes the cell from the candidate cells and thenchoose next candidate cell.4、If admission decisions have been made in all the candidate cells• For HSPA access, the HSPA request falls back to a DCH one. Then, the algorithm goes backto Step 1 to make an admission decision based on R99 service priorities.• For DCH access, the RNC initiates an inter-RAT DRD.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Key parametersService differential drd switchParameter ID: ServiceDiffDrdSwitchThe default value of this parameter is OFFService priority group IdentityParameter ID: PriorityServiceForR99RTService differential drd switchParameter ID: ServiceDiffDrdSwitchValue range: ON, OFFContent: This parameter specifies whether to enable the service steering DRD algorithmThe default value of this parameter is OFF.Set this parameter through ADD CELLDRDService priority of R99 RT serviceParameter ID: SpgIdValue range: 1 to 8Content: This parameter uniquely identifies a group of service priorities that map to cellsand indicate the support of each cell for the following service types: R99 RT service,R99 NRT service, HSPA service, and other services.Set this parameter through ADD SPG
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Service priority of R99 RT serviceParameter ID: SpgIdService priority of R99 NRT servicePriorityServiceForR99NRTService priority of HSPA servicePriorityServiceForHSPAService priority of Other servicePriorityServiceForExtRabKey parametersService priority of R99 RT serviceParameter ID: PriorityServiceForR99RTValue range: 0 to 7Content: This parameter specifies the support of the cells with a specific Service prioritygroup Identity for R99 RT services.The value 0 means that these cells do not support R99 RT services.For the values 1 through 7, the service priority is inversely proportional to the value, that is,the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest.Set this parameter through ADD SPG
    • Service priority of R99 NRT serviceParameter ID: PriorityServiceForR99NRTValue range: 0 to 7Content: This parameter specifies the support of the cells with a specific Service prioritygroup Identity for R99 NRT services.The value 0 means that these cells do not support R99 NRT services.For the values 1 through 7, the service priority is inversely proportional to the value, that is,the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest.Set this parameter through ADD SPGService priority of HSPA serviceParameter ID: PriorityServiceForHSPAValue range: 0 to 7Content: This parameter specifies the support of the cells with a specific Service prioritygroup Identity for HSPA services.The value 0 means that these cells do not support HSPA services.For the values 1 through 7, the service priority is inversely proportional to the value, that is,the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest.Set this parameter through ADD SPGService priority of Other serviceParameter ID: PriorityServiceForExtRabValue range: 0 to 7Content: This parameter specifies the support of the cells with a specific Service prioritygroup Identity for Other services .The value 0 means that these cells do not support Other service .For the values 1 through 7, the service priority is inversely proportional to the value, that is,the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest.Set this parameter through ADD SPG
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD for Load BalanceThe resources triggering DRD for Load Balance include:DL PowerOVSF codeAny of these 2 resources can trigger inter-frequency DRD forLoad BalanceLoad balancing considers two resources: power, and code.If both are activated, power-based load balancing DRD takes precedence over code-based load balancing DRD.Code-based load balancing DRD is applicable to only R99 services because HSDPAservices use reserved codes.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD procedure for DL Power Load BalanceThe procedure for the service steering DRD is as follows:1、The RNC determines candidate cells to which blind handovers can be performed and sortsthe candidate cells into a descending order according to service priority.A candidate cell must meet the following conditions:• The frequency of the candidate cell is within the band supported by the UE.• The quality of the candidate cell meets the Ec/No requirements of inter-frequencyDRD (DRD Ec/N0 Threshold )• The candidate cell supports the requested service.2、The RNC determines whether the DL radio load of the current cell is lower than the powerthreshold for load balancing DRD (condition 1 )power threshold for load balancing DRD is CAC parameter.•If the DL load of the current cell is lower than the threshold, the service tries admission tothe current cell.•If the DL load of the current cell is equal to or higher than the threshold, the RNC checksthe candidate cells to try to find out a target cell for UE access.RNC will check if there is a candidate cell will meet the following condition (condition 2 ) :•Ptotal_thd,nbcell is DL total power threshold for the inter-frequency neighboring cell.•Pload,nbcell is total power load of the inter-frequency neighboring cell. For a R99 cell, it isthe Downlink Transmitted Carrier Power of the cell, and for an HSPA cell, it is the non-HSDPA power and GBP.•Ptotal_thd,cutcell is DL total power threshold for the current cell.•Pload,cutcell is the total downlink load of the current cell.•Ploadoffset is the Power balancing drd offset of the current cell.
    • Then, the RNC selects the target cell as follows:• If there is only one inter-frequency neighboring cell that meets the load balancing DRDconditions, the RNC selects this cell as the target cell.• If there are multiple such cells, the RNC selects the cell with the lightest load as thetarget cell.• If there is no such cell, the RNC selects the current cell as the target cell.3、The CAC algorithm makes an admission decision based on the status of the target cell.• If the admission attempt is successful, the RNC accepts the service request.• If the admission attempt fails, the RNC removes the cell from the candidate cells andthen choose next candidate cell.4、If admission decisions have been made in all the candidate cells•For HSPA access, the HSPA request falls back to a DCH one. Then, the algorithm goesback to Step 1 to make an admission decision based on R99 service priorities.•For DCH access, the RNC initiates an inter-RAT DRD.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Power balance DRD switch on DCHParameter ID: LdbDrdSwitchDCHThe default value of this parameter is OFFPower balance DRD switch on HSDPAParameter ID: LdbDrdSwitchHSDPAThe default value of this parameter is OFFMax transmit power of cellParameter ID: MaxTxPowerThe default value of this parameter is 430 (43dBm)Dl power balancing drd power threshold for DCHParameter ID: LdbDRDOffsetDCHThe default value of this parameter is 10%Dl power balancing drd power threshold for HSDPAParameter ID: LdbDRDOffsetHSDPAThe default value of this parameter is 10%Key parametersPower balancing drd switchParameter ID: PowerBalancingDrdSwitchValue range: ON, OFFContent: This parameter specifies whether to enable the power-based loadbalancing DRD algorithm .The default value of this parameter is OFF.Set this parameter through SET DRD / ADD CELLDRDMax transmit power of cellParameter ID: MaxTxPowerValue range: 0 to 500 , step:0.1dBmContent: This parameter specifies the sum of the maximum transmit power ofall the downlink channels in a cell.The default value of this parameter is 430 (43dBm).Set this parameter through MOD CELLPower balancing drd offsetParameter ID: LoadBalanceDRDOffsetValue range: 0% to 100%Content: This parameter specifies the load offset threshold of the current celland the inter-frequency cell when power balancing drd algorithm is applied.Only when the cell load offset reaches this threshold, the inter-frequency cellcan be selected to be the target drd cell.The default value of this parameter is 10%Set this parameter through SET DRD / ADD CELLDRD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-frequency DRDInter-Frequency DRD procedure for Code Load BalanceThe procedure of load balancing DRD based on code resource is similar to that based on powerresource.1、The RNC determines whether the minimum remaining spreading factor of the current cell issmaller than Minimum SF threshold for code balancing drd.• If the minimum SF is smaller than Minimum SF threshold for code balancing drd, theRNC tries the admission of the service request to the current cell.• If the minimum SF is not smaller than Minimum SF threshold for code balancing drd,the RNC performs the next step .2、The RNC determines whether the code load of the current cell is lower than Code occupiedrate threshold for code balancing drd. .• If the code load is lower than Code occupied rate threshold for code balancing drd,the service tries the admission to the current cell.• If the code load is not lower than Code occupied rate threshold for code balancingdrd, the RNC selects the cell with the lightest code load or the current cell as the targetcell.3、The RNC selects the cell as follows:• If the difference between the code resource occupancies of the cell and the current cellis larger than the value of Delta code occupied rate , the RNC selects the cell with thelightest code load as the target cell. Otherwise, the RNC selects the current cell as thetarget cell.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Code balancing drd switchParameter ID: CodeBalancingDrdSwitchThe default value of this parameter is OFFMinimum SF threshold for code balancing drdParameter ID: CodeBalancingDrdMinSFThdThe default value of this parameter is SF8Key parametersCode balancing drd switchParameter ID: CodeBalancingDrdSwitchValue range: ON, OFFContent: This parameter specifies whether to enable the code-based loadbalancing DRD algorithm.The default value of this parameter is OFF.Set this parameter through SET DRD / ADD CELLDRDMinimum SF threshold for code balancing drdParameter ID: CodeBalancingDrdMinSFThdValue range: SF4, SF8, SF16, SF32, SF64, SF128, SF256Content: If the downlink minimum SF of the best cell is below this threshold,the code-based load balancing DRD is not triggered.The default value of this parameter is SF8 .Set this parameter through SET DRD / ADD CELLDRD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Code occupied rate threshold for code balancing drdParameter ID: CodeBalancingDrdCodeRateThdThe default value of this parameter is 13%Delta code occupied rateParameter ID: DeltaCodeOccupiedRateThe default value of this parameter is 7%Key parametersCode occupied rate threshold for code balancing drdParameter ID: CodeBalancingDrdCodeRateThdValue range: 0% to 100%Content: This parameter specifies the code occupancy threshold of the current cell forcode-based load balancing DRD.Only when the code occupancy of the best cellreaches this threshold can code-based load balancing DRD be triggered.The default value of this parameter is 13%.Set this parameter through SET DRD / ADD CELLDRDDelta code occupied rateParameter ID: DeltaCodeOccupiedRateValue range: 0% to 100%Content: This parameter specifies the code occupied rate offset threshold of thecurrent cell and the inter-frequency cell when code balancing drd algorithm is applied.Only when the code occupied rate offset reaches this threshold, the inter-frequencycell can be selected to be the target drd cell.The default value of this parameter is 7% .Set this parameter through SET DRD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Inter-RAT DRDInter-RAT DRDInter-RAT DRD is available for AMR service only in RAN 10:The inter-RAT DRD procedure is as follows:1,If the current cell is configured with any neighboring GSM cell suitable for blind handoverand the Service Handover Indicator is set to HO_TO_GSM_SHOULD_BE_PERFORM,the RNC performs next step. Otherwise, the service request undergoes preemption andqueuing.2,The RNC generates a list of candidate DRD-supportive inter-RAT cells that fulfill the Ec/Nothreshold.3,The service request then tries admission to a target GSM cell in order of blind handoverpriority.4,If all admission attempts fail or the number of inter-RAT directed retries exceeds the valueof Max inter-RAT direct retry number, the service request undergoes preemption andqueuing.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Max inter-RAT direct retry numberParameter ID: DRMaxGSMNumThe default value of this parameter is 2Key parametersMax inter-RAT direct retry numberParameter ID: DRMaxGSMNumValue range: 0 to 5Content: This parameter defines the maximum number of inter-RAT directedretries for an RAB. The value 0 means that inter-RAT DRD is not allowed.The default value of this parameter is 2Set this parameter through ADD CELLDRD
    • Preemption and Queuing guarantees the success in the access of a higher-priority userby forcibly releasing the resources of a lower-priority user.After cell resource admission fails, the RNC performs Preemption and Queuing if thefollowing conditions are met:The RNC receives an RAB ASSIGNMENT REQUEST message indicating thatPreemption and Queuing is supported.By default, Preemption and Queuing setting in CN may be:Preemption and Queuing is applicable to the following cases:Setup or modification of a serviceHard handover or SRNS relocationUE state transits from CELL_FACH to CELL_DCHThe RNC selects a suitable cell according to the settings of the DRD algorithms.Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – Preemption and QueuingAfter cell admission fails, the RNC performs preemptionand QueuingPrecondition of Preemption and Queuing– According to CN setting, Preemption and Queuing is supportedTarget cell of Preemption and Queuing– Based on DRDNotallowedallowedNot ableLowallowedallowedAbleMediumallowedNot allowedAbleHighQueuingPreemptablePreemptioncapabilityUSERLEVEL
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – PreemptionPreemption on different resources√√-Number ofusers√√√Iub bandwidth---CE√√√Power---CodeHSDPAservice√√√Iub bandwidth√-√CE√√√Power√-√CodeR99 serviceR99 + HSPA Combined ServiceHSDPA ServiceR99 ServiceService That can Be PreemptedResourceServiceThe preemption procedure is as follows:1、The preemption algorithm determines which radio link sets can be preempted. Thealgorithm proceeds as follows:Chooses SRNC users first. If no user under the SRNC is available, thealgorithm chooses users under the DRNC.Sorts the pre-emptable users by user integrate priority, or sorts the pre-emptable RABs by RAB integrate priority.Determines candidate users or RABs.Only the users or RABs with priorities lower than the RAB to beestablished are selected.Selects as many users or RABs as necessary in order to match the resourceneeded by the RAB to be established. When the priorities of two users orRABs are the same, the algorithm chooses the user or RAB that can releasethe most resources.2、The RNC releases the resources occupied by the candidate users or RABs.3、The requested service directly uses the released resources to access the networkwithout admission decision.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Preempt algorithm switchParameter ID: PREEMPTALGOSWITCHThe default value of this parameter is OFFKey parametersPreempt algorithm switchParameter ID: PREEMPTALGOSWITCHValue range: ON, OFFContent: This parameter specifies whether to support the preemption function.The default value of this parameter is OFFSet this parameter through SET QUEUEPREEMPT
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.IAC – QueuingAfter Preemption rejection, UE can wait in queue, thenadmission attempts for the service are made periodically tillTmax expires.Admission attempts are made based on Queuing priority:Pqueue = Tmax – TelapsedTmax is the maximum time in the queue, default value is 5sTelapsed is the time has queuedAfter the cell resource decision fails, the RNC performs queuing if the RNC receives an RABASSIGNMENT REQUEST message indicating the queuing function is supportedThe queuing algorithm checks whether the queue is full, that is, whether the number of servicerequests in the queue exceeds the queue length that is defined by the Queue lengthThe queuing algorithm is triggered by the heartbeat timer, which is set through the Poll timerlength .If the queue is not full:• Stamps this request with the current time.• Puts this request into the queue.If the queue is full:• Checks whether there are requests whose integrate priorities are lower than that ofthe priority of the new request. If there is, delete the low priority request, put the newservice in the queue. (Otherwise, the queuing algorithm rejects the new requestdirectly.)• Stamps the new request with the current time and then puts it into the queue.After the heartbeat timer (Poll timer length) expires, the queuing algorithm proceeds as follows:• Selects the request with the highest integrate priority for an attempt of resourceallocation .• If the attempt fails, the queuing algorithm proceeds as follows:• Puts the service request back into the queue with the time stampunchanged for the next attempt.• Chooses the request with the greatest weight from the rest and makesanother attempt until a request is accepted or all requests are rejected.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Queue algorithm switchParameter ID: QUEUEALGOSWITCHThe default value of this parameter is OFFQueue lengthParameter ID: QUEUELENThe default value of this parameter is 5Key parametersQueue algorithm switchParameter ID: QUEUEALGOSWITCHValue range: ON, OFFContent: This parameter specifies whether to support the queuing function.The default value of this parameter is OFFSet this parameter through SET QUEUEPREEMPTQueue lengthParameter ID: QUEUELENValue range: 5 to 20Content: This parameter defines the length of a queue.The default value of this parameter is 5Set this parameter through SET QUEUEPREEMPT
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Poll timer lengthParameter ID: POLLTIMERLENThe default value of this parameter is 50 (500ms)Max queuing time lengthParameter ID: MAXQUEUETIMELENThe default value of this parameter is 5Key parametersPoll timer lengthParameter ID: POLLTIMERLENValue range: 1 to 6000 , step: 10msContent: This parameter defines the length of the heartbeat timer. Each time the timerexpires, the RNC chooses the service that meets the requirement to make anadmission attempt .The default value of this parameter is 50 (500ms)Set this parameter through SET QUEUEPREEMPTMax queuing time lengthParameter ID: MAXQUEUETIMELENValue range: 1 to 60sContent: This parameter defines the maximum time that the service request can be inthe queue.The default value of this parameter is 5sSet this parameter through SET QUEUEPREEMPT
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LCC (Load Congestion Control)Overload state: OLC will beusedLoad%THLDRTHOLC100%section Asection Bsection C1 2Normal state: Permit entryTimesBasic congestion state: LDRwill be usedLCC (Load Congestion Control) consist of LDR (Load Reshuffling) and OLC (Over LoadControl).In basic congestion state, LDR will be used to optimize resource distribution, the mainrules is not to affect the feeling of users as possible as we can.In overload state, OLC will be used to release overload state quickly, keep system stabilityand the service of high priority users.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load ReshufflingReasonsWhen the cell is in basic congestion state, new coming callscould be easily rejected by systemPurposeOptimizing cell resource distributionDecreasing load level, increasing admission successful rateWhen the usage of cell resource exceeds the basic congestion triggering threshold, thecell enters the basic congestion state. In this case, LDR is required to reduce the cell loadand increase the access success rate.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load ReshufflingTriggering of LDRPower resourcesCode resourceIub resourcesNodeB Credit resourceFor power resource, the RNC performs periodic measurement and checks whether thecells are congested. For code, Iub, and NodeB credit resources, event-triggered congestionapplies, that is, the RNC checks whether the cells are congested when resource usagechanges.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Load ReshufflingLDR Actions:Inter-frequency load handoverCode reshufflingBE service rate reductionAMR rate reductionInter-RAT load handover in the CS domainInter-RAT load handover in the PS domainReal time service Iu QoS renegotiationMBMS power reductionWhen the cell is in basic congestion state, the RNC takes one of the actions in eachperiod until the congestion is resolved
    • Load Reshuffling Actions triggered by different resourcesIf the downlink power admission uses the equivalent user number algorithm, basic congestion can also betriggered by the equivalent number of users. In this situation, LDR actions do not involve AMR ratereduction or MBMS power reduction, as indicated by the symbol "*" in above tableCongestion of different resource may trigger different actions.For example, Credit congestion do not trigger “Inter-Frequency Load Handover”, “AMR RateReduction”, and “Code Reshuffling”When congestion of all resources is triggered, the action to be taken is based on the resource priorityconfiguration.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell LDC algorithm switchParameter ID: NBMLDCALGOSWITCHUL_UU_LDRDL_UU_LDRCELL_CODE_LDRNodeB LDC algorithm switchParameter ID: NodeBLdcAlgoSwitchIUB_LDRNODEB_CREDIT_LDRKey parametersCell LDC algorithm switchParameter ID: NBMLDCALGOSWITCHValue range: ON, OFFContent: If ULLDR, DLLDR, CELL_CODE_LDR are selected, the correspondingalgorithms are enabled. .Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCHNodeB LDC algorithm switchParameter ID: NodeBLdcAlgoSwitchValue range: ON, OFFContent: If IUB_LDR, NODEB_CREDIT_LDR, are selected, the correspondingalgorithms will be enabled; otherwise, disabled. .Set this parameter through ADD NODEBALGOPARA / MOD NODEBALGOPARA /SET LDCALGOPARA
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL (RTWP) LDR trigger thresholdParameter ID: ULLDRTRIGTHDThe default value of this parameter is 55%UL (RTWP) LDR release thresholdParameter ID: ULLDRRELTHDThe default value of this parameter is 45%Key parametersUL LDR trigger thresholdParameter ID: ULLDRTRIGTHDValue range: 0 to 100 , %Content: If the UL load of the cell is not lower than this threshold, the UL loadreshuffling function of the cell is triggered.The default value of this parameter is 55%Set this parameter through ADD CELLLDM/MOD CELLLDMUL LDR release thresholdParameter ID: ULLDRRELTHDValue range: 0 to 100 , %Content: If the UL load of the cell is lower than this threshold, the UL load reshufflingfunction of the cell is stopped.The default value of this parameter is 45%Set this parameter through ADD CELLLDM / MOD CELLLDM
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL (TX POWER) LDR trigger thresholdParameter ID: DLLDRTRIGTHDThe default value of this parameter is 70%DL (TX POWER) LDR release thresholdParameter ID: DLLDRRELTHDThe default value of this parameter is 60%Key parametersDL LDR trigger thresholdParameter ID: DLLDRTRIGTHDValue range: 0 to 100 , %Content: If the DL load of the cell is not lower than this threshold, the DL loadreshuffling function of the cell is triggered.The default value of this parameter is 70%Set this parameter through ADD CELLLDM / MOD CELLLDMDL LDR release thresholdParameter ID: DLLDRRELTHDValue range: 0 to 100 , %Content: If the DL load of the cell is lower than this threshold, the DL load reshufflingfunction of the cell is stopped.The default value of this parameter is 60%Set this parameter through ADD CELLLDM / MOD CELLLDM
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell LDR SF reserved thresholdParameter ID: CELLLDRSFRESTHDThe default value of this parameter is SF8Ul LDR Credit SF reserved thresholdParameter ID: ULLDRCREDITSFRESTHDThe default value of this parameter is SF8Dl LDR Credit SF reserved thresholdParameter ID: DLLDRCREDITSFRESTHDThe default value of this parameter is SF8Key parametersCell LDR SF reserved thresholdParameter ID: CELLLDRSFRESTHDValue range: SF4, SF8, SF16, SF32, SF64, SF128, SF256Content: If the SF corresponding to the current remaining code of the cell is higher thanthe threshold defined by this parameter, code congestion is triggered and the relatedhandling actions are taken.The default value of this parameter is SF8Set this parameter through ADD CELLLDR / MOD CELLLDRUl LDR Credit SF reserved thresholdParameter ID: ULLDRCREDITSFRESTHDValue range: 0 to 100 , %Content: If the SF corresponding to the current UL remaining credit resource is higherthan the threshold defined by this parameter, the UL credit LDR can be performed andthe related handling actions are taken.The default value of this parameter is 60%Set this parameter through ADD NODEBLDR/MOD NODEBLDRDl LDR Credit SF reserved thresholdParameter ID: DLLDRCREDITSFRESTHDValue range: 0 to 100 , %Content: If the value of SF corresponding to the current DL remaining credit resource ishigher than the threshold defined by this parameter, the DL credit LDR can beperformed and the related handling actions are taken.The default value of this parameter is SF8Set this parameter through ADD NODEBLDR/MOD NODEBLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.The First / Second/ Third/ Fourth priority for load reshufflingParameter ID:LdrFirstPriLdrSecondPriLdrThirdPriLdrFourthPriThe default configuration is :IUBLDR > CREDITLDR > CODELDR > UULDRKey parametersThe First / Second/ Third/ Fourth priority for load reshufflingParameter ID: LdrFirstPri / LdrSecondPri / LdrThirdPri / LdrFourthPriValue range: IUBLDR(Iub load reshuffling), CREDITLDR(Credit load reshuffling),CODELDR (Code load reshuffling), UULDR (Uu load reshuffling)Content: These parameters specify the triggering resource order when congestion of allresources are triggered.The default configuration is IUBLDR > CREDITLDR > CODELDR > UULDRSet this parameter through SET LDCALGOPARA
    • LDR procedureMark "current LDR state = uncongested"Wait for congestion indicationCongestionstate indicationTurn on LDR algorithm switchCurrent LDR state = congested?Start LDM congestion indication reportMark "current action = first LDR action"Clear "selected" mark of all UE LDR actionsSequence ofactions can beconfigured(current actionis taken firstly)Inter-systemhandoverin CS domainAMR ratereductionInter-freqload handoverQoS renogiationon Iu interfaceBE ratereductionSucceed?Mark"current action= successfulaction"Wait timefor LDRaction durationYYYYYNNNNNNMark "current action = first LDR action"No related action can be foundNInter-systemhandoverin PS domainSucceed?Succeed?Succeed?Succeed?Succeed?CodereshufflingSucceed?YNMBMS powerreductionNSucceed?YY
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR period timer lengthParameter ID: LDRPERIODTIMERLEThe default value of this parameter is 10 sGold User Load Control SwitchParameter ID: GoldUserLoadControlSwitchThe default value of this parameter is OFFKey parametersLDR period timer lengthParameter ID: LDRPERIODTIMERLEValue range: 0 to 86400 sContent: This parameter specifies the period of load reshuffling .The default value of this parameter is 10 sSet this parameter through SET LDCPERIODGold User Load Control SwitchParameter ID: GoldUserLoadControlSwitchValue range: ON, OFFContent: This parameter specifies whether LDR actions are applicable to users of goldpriority.The default value of this parameter is OFFSet this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL LDR first / second / third / fourth / fifth / sixth / seventh /eighth / ninth / tenth actionParameter ID:DlLdrFirstAction / DlLdrSecondAction / DlLdrThirdAction /DlLdrFourthAction / DlLdrFifthAction / DlLdrSixthAction /DlLdrSeventhAction / DlLdrEighthAction / DlLdrNinthAction /DlLdrTenthActionThe default configuration is :1st:CODEADJ , 2nd: INTERFREQLDHO , 3rd: BERATEREDKey parametersDL LDR first / second / third / fourth / fifth / sixth / seventh / eighth / ninth / tenth actionParameter ID: DlLdrFirstAction / DlLdrSecondAction / DlLdrThirdAction /DlLdrFourthAction / DlLdrFifthAction / DlLdrSixthAction / DlLdrSeventhAction /DlLdrEighthAction / DlLdrNinthAction / DlLdrTenthActionValue range: NOACT (NO ACTION), INTERFREQLDHO (INTER-FREQ LOADHANDOVER), BERATERED (BE TRAFF RATE REDUCTION), QOSRENEGO(UNCONTROLLED REAL-TIME TRAFF QOS RE-NEGOTIATION),CSINTERRATSHOULDBELDHO (CS DOMAIN INTER-RAT SHOULD BE LOADHANDOVER), PSINTERRATSHOULDBELDHO (PS DOMAIN INTER-RAT SHOULDBE LOAD HANDOVER), AMRRATERED (AMR TRAFF RATE REDUCTION),MBMSDECPOWER(MBMS DESCEND POWER), CODEADJ(CODE ADJUST),CSINTERRATSHOULDNOTLDHO (CS DOMAIN INTER-RAT SHOULD NOT BELOAD HANDOVER), PSINTERRATSHOULDNOTLDHO (PS DOMAIN INTER-RATSHOULD NOT BE LOAD HANDOVER).Content: These parameters specify the LDR action order.The default configuration is 1st:CODEADJ , 2nd: INTERFREQLDHO , 3rd:BERATERED ,Set this parameter through ADD CELLLDR / MOD CELLLDR / ADD NODEBLDR /MOD NODEBLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsInter-frequency load handoverTarget usersBased on user integrate priorityCurrent bandwidth for DCH or “GBR bandwidth for HSPA” has to be lessthan the UL/DL Inter-freq cell load handover maximum bandwidthparameterTarget cellsLoad difference between current load and the basic congestion triggerthreshold of target cell is larger than “UL/DL Inter-freq cell load handoverload space threshold”It is implemented as follows:1. The LDR check whether the existing cell has a target cell of inter-frequency blind handover. If there is nosuch a target cell, the action fails, and the LDR performs the next action.2. The principles of selecting inter-freq handover target cell are different as a result of the different resourceswhich trigger the basic congestion.1. If the basic congestion is triggered by the power resource:The LDR checks whether the load difference between the current load and the basic congestion triggeringthreshold of each target cell for blink handover is larger than the UL/DL Inter-freq cell load handover loadspace threshold (both the uplink and downlink conditions must be fulfilled). The other resources (coderesource, Iub bandwidth, and NodeB credit resource) in the target cell do not trigger basic congestion.If the difference is not larger than the threshold, the action fails, and the LDR takes the next action.If there are more than one cell meeting the requirements, the first one is selected as the blind handovertarget cell.2. If the basic congestion is triggered by the code resource:Weather there are blind handover target cells meeting the requirements is decided by the followingconditions:The minimum SF of the target cell is not greater than that of current cell.The difference of code occupy rate between current cell and the target cell is greater than InterFreq HOcode used ratio space threshold.The state of target cell is normal.If there is no such cell, this action fails and the LDR performs the next action. If there are more than one cellmeeting the requirements, the first cell is selected as the blind handover target cell.3. If the LDR finds out a target cell that meets the specified blind handover conditions, the LDR selects one UEto make an inter-frequency blind handover, depending on the UE’s ARP and occupied bandwidth. For theselected UE other than a gold user, its UL/DL current bandwidth for DCH, GBR bandwidth for HSPA, shall beless than and have the least difference from the UL/DL Inter-freq cell load handover maximum bandwidthparameter (Both the uplink and downlink condition must be fulfilled). If the LDR cannot find such a UE, theaction fails. The LDR performs the next action.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL/DL Inter-freq cell load handover load space thresholdParameter ID: UL/DLINTERFREQHOCELLLOADSPACETHDThe default value of this parameter is 20InterFreq HO code used ratio space thresholdParameter ID: LdrCodeUsedSpaceThdThe default value of this parameter is 13UL/DL Inter-freq cell load handover maximum bandwidthParameter ID: UL/DLINTERFREQHOBWTHDThe default value of this parameter is 200000Key parametersUL/DL Inter-freq cell load handover load space thresholdParameter ID: UL/DLINTERFREQHOCELLLOADSPACETHDValue range: 0 to 11 %Content: The target cell can be a cell for inter-frequency blind handover only when theUL/DL load space is higher than the threshold.The UL/DL load space is the difference between the UL/DL basic congestion triggeringthreshold and the current UL/DL load of a target cell for blind handover. .The default value of this parameter is 20%Set this parameter through ADD CELLLDR / MOD CELLLDRInterFreq HO code used ratio space thresholdParameter ID: LdrCodeUsedSpaceThdValue range: 0% to 100% (0~1) ,step:1%Content: The target cell can be used for inter-frequency blind handover only when theDL Code used ratio space is higher than the threshold. The DL Code used ratio spaceis the difference of code used ratio between the source cell and the target cell.The default value of this parameter is 13%Set this parameter through ADD CELLLDR / LST CELLLDR / MOD CELLLDRUL/DL Inter-freq cell load handover maximum bandwidthParameter ID: UL/DLINTERFREQHOBWTHDValue range: 0 to 400000 bpsContent: During the inter-frequency load handover, the UE is selected as the target ofinter-frequency load handover from the UE set where the bandwidth is less than thisthreshold.The default value of this parameter is 200000Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsBE Rate ReductionTarget RABsBased on RAB integrate priorityThe data rate of BE service is larger than GBRNumber of RABs to be selected is configurableBE rate reduction is implemented by reconfiguring the bandwidth. Bandwidthreconfiguration requires signaling interaction on the Uu interface.The LDR algorithm is implemented as follows:1. Based on the integrate priority, the LDR sorts the RABs into a descending order. Thetop RABs related to the BE services (whose current rate is higher than its GBRconfigured by SET USERGBR command) are selected. If the integrate priorities ofsome RABs are identical, the RAB with the highest rate is selected. The number ofRABs to select is determined by the UL/DL LDR-BE rate reduction RAB numberparameter.2. The bandwidth of the selected services is reduced to the specified rate.3. If services can be selected, the action is successful. If services cannot be selected, theaction fails. The LDR takes the next action.4. The reconfiguration is completed as indicated by the RB RECONFIGURATIONmessage on the Uu interface and through the RL RECONFIGURATION message onthe Iub interface.5. The BE rate reduction algorithm is controlled by the DCCC algorithm switch. BE ratereduction can be performed only when the DCCC algorithm is enabled.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL /DL LDR-BE rate reduction RAB numberParameter ID: UL/DLLDRBERATEREDUCTIONRABNUMThe default value of this parameter is 1Key parametersUL /DL LDR-BE rate reduction RAB numberParameter ID: UL/DLLDRBERATEREDUCTIONRABNUMValue range: 1 to 10Content: These parameters specify the number of RABs to select in a UL/DL LDR BErate reduction.If the number of RABs that fulfil the criteria for BE rate reduction is smaller than thevalue of this parameter, then all the RABs that fulfil the criteria are selected.The default value of this parameter is 1Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsUncontrolled Real-time service QoS RenegotiationTarget RABsBased on RAB integrate priorityReal-time services in the PS domainThe load is reduced by adjusting the rate of the real-time services through uncontrolled real-time OoS renegotiation.Upon receipt of the message, the CN sends the RAB ASSIGNMENT REQUEST messageto the RNC for RAB parameter reconfiguration. Based on this function, the RNC canadjust the rate of real-time services to reduce the load.The LDR algorithm is implemented as follows:1. Based on the integrate priority, the LDR sorts the real-time services in the PS domain indescending order. The top services are selected for QoS renegotiation.2. The LDR performs QoS renegotiation for the selected services. The GBR duringservice setup is the rate of the service after QoS renegotiation.3. The RNC initiates the RAB Modification Request message to the CN for QoSrenegotiation.4. If the RNC cannot find a proper service for QoS renegotiation, the action fails. The LDRperforms the next action.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL / DL LDR un-ctrl RT Qos re-nego RAB numParameter ID: UL/DLLDRPSRTQOSRENEGRABNUMThe default value of this parameter is 1Key parametersUL / DL LDR un-ctrl RT Qos re-nego RAB numParameter ID: UL/DLLDRPSRTQOSRENEGRABNUMValue range: 1 to 10Content: These parameters specify the number of RABs to select in a UL/DL LDRuncontrolled real-time QoS renegotiation.If the number of RABs that fulfil the criteria for uncontrolled real-time QoS renegotiationis smaller than the value of this parameter, then all the RABs that fulfil the criteria areselected.The default value of this parameter is 1Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsInter-system Handover In the CS/PS DomainTarget userBased on the user integrate priorityHandover Indicator– “Handover to GSM should be performed”– "handover to GSM should not be performed"WCDMA cellGSM cellThe 2G and 3G systems have different cell sizes and coverage modes. Therefore, blindhandover across systems is not taken into account.The LDR is implemented in the downlink (e.g.) as follows:1. Based on the integrate priority, the LDR sorts the UEs in descending order. The topCS/PS services are selected.2. For the selected UEs, the LDR sends the load handover command to the inter-systemhandover module to ask the UEs to hand over to the 2G system.3. The handover module decides to trigger inter-system handover, depending on thecapability of the UE and the capability of the algorithm switch to support thecompression mode.4. This action is successful if any load handover UE is found. Otherwise, this action fails.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL / DL CS should be ho user numberParameter ID: UL/DLCSINTERRATSHOULDBEHOUENUMThe default value of this parameter is 3UL / DL CS should not be ho user numberParameter ID: UL/DLCSINTERRATSHOULDNOTBEHOUENUMThe default value of this parameter is 3Key parametersUL / DL CS should be ho user numberParameter ID: UL/DLCSINTERRATSHOULDBEHOUENUMValue range: 1 to 10Content: These parameters specify the number of users to select in a UL/DL Inter-RATShould Be Load Handover in the CS Domain.If the number of users that fulfil the criteria for Inter-RAT Should Be Load Handover in theCS Domain is smaller than the value of this parameter, then all the users that fulfil thecriteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLLDR / MOD CELLLDRUL / DL CS should not be ho user numberParameter ID: UL/DLCSINTERRATSHOULDNOTBEHOUENUMValue range: 1 to 10Content: These parameters specify the number of users to select in a UL/DL Inter-RATShould Not Be Load Handover in the CS Domain.If the number of users that fulfil the criteria for Inter-RAT Should Not Be Load Handoverin the CS Domain is smaller than the value of this parameter, then all the users that fulfilthe criteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL / DL PS should be ho user numberParameter ID: UL/DLPSINTERRATSHOULDBEHOUENUMThe default value of this parameter is 3UL / DL PS should not be ho user numberParameter ID: UL/DLPSINTERRATSHOULDNOTBEHOUENUMThe default value of this parameter is 3Key parametersUL / DL PS should be ho user numberParameter ID: UL/DLPSINTERRATSHOULDBEHOUENUMValue range: 1 to 10Content: These parameters specify the number of users to select in a UL/DL Inter-RATShould Be Load Handover in the PS Domain.If the number of users that fulfil the criteria for Inter-RAT Should Be Load Handover inthe PS Domain is smaller than the value of this parameter, then all the users that fulfilthe criteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLLDR / MOD CELLLDRUL / DL PS should not be ho user numberParameter ID: UL/DLPSINTERRATSHOULDNOTBEHOUENUMValue range: 1 to 10Content: These parameters specify the number of users to select in a UL/DL Inter-RATShould Not Be Load Handover in the PS Domain.If the number of users that fulfil the criteria for Inter-RAT Should Not Be Load Handoverin the PS Domain is smaller than the value of this parameter, then all the users that fulfilthe criteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsAMR Rate ReductionTarget userAMR services and with the bit rate higher than the GBRBased on RAB integrate priorityIn the WCDMA system, voice services work in eight AMR modes. Each mode has its ownrate. Therefore, mode control is functionally equal to rate control.The LDR algorithm is implemented as follows:1. Based on the integrate priority, the LDR sorts the RABs in the descending order. The topUEs accessing the AMR services (conversational) and with the bit rate higher than theGBR are selected.2. In uplink, the RNC sends the “Rate Control request” message through the Iu-UP to theCN to adjust the AMR rate to the GBR.3. In downlink, The RNC sends the TFC CONTROL command to the UE to adjust the AMRrate to the assured rate.4. If the RNC cannot find a proper service for AMR rate reduction, the action fails. The LDRperforms the next action.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL/DL LDR-AMR rate reduction RAB numberParameter ID: UL/DLLDRAMRRATEREDUCTIONRABNUMThe default value of this parameter is 3Key parametersUL/DL LDR-AMR rate reduction RAB numberParameter ID: UL/DLLDRAMRRATEREDUCTIONRABNUMValue range: 1 to 10Content: These parameters specify the number of RABs to select in a UL/DL LDR AMRrate reduction.If the number of RABs that fulfil the criteria for AMR rate reduction is smaller than thevalue of this parameter, then all the RABs that fulfil the criteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsCode ReshufflingReallocate code resources for candidate userCode AdjustmentThe algorithm operates as follows:1,Initialize the SF_Cur of the root node of subtrees to Cell LDR SF reserved threshold.2,Traverse all the subtrees with this SF_Cur at the root node. Leaving the subtreesoccupied by common channels and HSDPA channels out of account, take thesubtrees in which the number of users is not larger than the value of the Max usernumber of code adjust parameter as candidates for code reshuffling.3,Select a subtree from the candidates according to the setting of the LDR code priorityindicator parameter.If this parameter is set to TRUE, select the subtree with the largest codenumber from the candidates.If this parameter is set to FALSE, select the subtree with the smallestnumber of users from the candidates. In the case that multiple subtrees havethe same number of users, select the subtree with the largest code number.4,Treat each user in the subtree as a new user and allocate code resources to each user.5,Initiate the reconfiguration procedure for each user in the subtree and reconfigure thechannel codes of the users to the newly allocated code resources.The reconfiguration procedure on the air interface is implemented through the PHYSICALCHANNEL RECONFIGURATION message and that on the Iub interface through theRL RECONFIGURATION message.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Max user number of code adjustParameter ID: MAXUSERNUMCODEADJThe default value of this parameter is 1LDR code priority indicatorParameter ID: LdrCodePriUseIndThe default value of this parameter is TRUEKey parametersMax user number of code adjustParameter ID: MAXUSERNUMCODEADJValue range: 1 to 3Content: This parameter specifies the maximum number of users that can be selectedwhenever code reshuffling is performed.The default value of this parameter is 1Set this parameter through ADD CELLLDR / MOD CELLLDRLDR code priority indicatorParameter ID: LdrCodePriUseIndValue range: True, FalseContent: This parameter specifies whether to select preferentially the subtree with arelatively large code number during subtree selection.Set this parameter through ADD CELLLDR / MOD CELLLDR
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.LDR ActionsMBMS Power ReductionPurposeThe downlink power load can be reduced by lowering power onMBMS traffic channelsThe LDR algorithm is implemented as follows:1. Select all RABs with low priorities.2. The RNC initiates the reconfiguration procedure and resets the transmit power ofMTCH (FACH) to the minimum value. The transmit power corresponds to the MBMSservice.3. The reconfiguration procedure on the Iub interface is implemented through theCOMMON TRANSPORT CHANNEL RECONFIGURATION REQUEST message.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Contents2. Load Control Algorithms2.1 PUC (Potential User Control)2.2 LDB (Intra-Frequency Load Balancing)2.3 CAC (Call Admission Control)2.4 IAC (Intelligent Admission Control)2.5 LDR (Load Reshuffling)2.6 OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Over Load ControlReasonsIn overload state, system is not stablePurposeEnsuring the system stability and making the system back tothe normal state as soon as possibleTriggering of Over LoadPower resourceAfter the UE access is granted, the power consumed by a single link is adjusted by thesingle link power control algorithm. The power varies with the mobility of the UE and thechanges in the environment and the source rate. In some situations, the total power load ofthe cell may be higher than the target load. To ensure system stability, overload congestionmust be handled.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Over Load ControlOver Load triggeringIf the current UL/DL load of an R99 cell is not lower than the UL/DL OLC Triggerthreshold for some hysteresis (defined by the DL State Trans Hysteresis threshold inDL; not configurable in UL), the cell works in overload congestion state and the relatedoverload handling action is taken. If the current UL/DL load of the R99 cell is lower than theUL/DL OLC Release threshold for some hysteresis (defined by the DL State TransHysteresis threshold in DL; not configurable in UL), the cell comes back to the normalstate.The HSPA cell has the same uplink decision criterion as the R99 cell. The load in thedownlink, however, is the sum of load of the non-HSPA power (transmitted carrier power ofall codes not used for HS-PDSCH or HS-SCCH transmission) and the GBP..
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Cell LDC algorithm switchParameter ID: NBMLDCALGOSWITCHUL_UU_OLC, DL_UU_OLCUL/DL OLC trigger thresholdParameter ID: UL/DLOLCTRIGTHDThe default value of this parameter is 95%UL/DL OLC release thresholdParameter ID: UL/DLOLCRELTHDThe default value of this parameter is 85%Key parametersCell LDC algorithm switchParameter ID: NBMLDCALGOSWITCHValue range: OFF, ONContent: This parameter specifies the switch of UL/DL OLC.UL_UU_OLC: UL overload control algorithmDL_UU_OLC: DL overload control algorithmSet this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCHUL/DL OLC trigger thresholdParameter ID: UL/DLOLCTRIGTHDValue range: 0 to 100 %Content: If the UL load of the cell is not lower than the value of the UL OLC triggerthreshold, the UL overload congestion control of the cell is activated.If the DL load of the cell is not lower than the value of the DL OLC trigger threshold,the DL overload congestion control of the cell is activated.Set this parameter through ADD CELLLDR / MOD CELLLDRUL/DL OLC release thresholdParameter ID: UL/DLOLCRELTHDValue range: 0 to 100 %Content: If the UL load of the cell is lower than the value of the UL OLC releasethreshold, the UL overload congestion control of the cell is deactivated.If the DL load of the cell is lower than the value of the DL OLC release threshold, theDL overload congestion control of the cell is deactivated.Set this parameter through ADD CELLLDR / MOD CELLLDR
    • The general OLC procedure covers the following actions: TF control of BE services, channelswitching of BE services, and release of RABs. The RNC takes periodical actions if overloadcongestion is detected.When the cell is overloaded, the RNC takes one of the following actions in each period (defined bythe OLC period timer length parameter, e.g.3s) until the congestion is resolved:1. TF control of BE service (only for DCH BE service)2. Switching BE services to common channel3. Choosing and releasing the RABs (for HSPA or DCH service)If the first action fails or the first action is completed but the cell is still in congestion, then thesecond action is taken.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.OLC period timer lengthParameter ID: OLCPERIODTIMERLENThe default value of this parameter is 3000 (ms)Key parametersOLC period timer lengthParameter ID: OLCPERIODTIMERLENValue range: 100 to 86400000Content: This parameter specifies the period of overload control.The default value of this parameter is 3000 (ms)Set this parameter through SET LDCPERIOD
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.OLC ActionTF ControlTarget userBased on RAB integrate priorityThe RABs with the DCH BE servicesExecutionThe RNC sends the “TF control indication” message to the MAC.MAC restricts the TFC selection :TFmax(N+1) = TFmax(N) x RatelimitcoeffBased on the RAB integrate priority, the OLC sorts the RABs into a descending order.Thefollowing RABs are selected:1. The RABs with the DCH BE services2. The RABs with the lowest integrate priority.3. The number of RABs selected is DL/UL OLC fast TF restrict RAB number.The RNC sends the TF control indication message to the MAC. Each MAC of selectedRABs will receive one TF control indication message and will restrict the TFC selectionof the BE services to reduce the data rate step by step.MAC restricts the TFC selection in a way like that the maximum TB number is calculatedwith the formula:TFmax(N+1) = TFmax(N) x RatelimitcoeffRatelimitcoeff is a configurable parameter (DL OLC fast TF restrict data rate restrictcoefficient).If the RNC cannot find an appropriate service for the TF control or the time for performingthe TF control exceed the DL OLC fast TF restrict times parameter, the action fails.The OLC performs the next action.If the congestion is released, the RNC sends the congestion release indication to the MAC.At the same time, the rate recovery timer (whose length is defined by DL OLC fast TFrestrict data rate recover timer length) is started. When this timer is expired, theMAC increases the data rate step by step.MAC recovers the TFC selection by calculating the maximum TB number with the formula:TFmax(N+1) = TFmax(N) x RateRecoverCoeffRateRecoverCoeff is a configurable parameter (DL TF rate recover coefficient)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.OLC ActionTF Control exampleBefore point A, the cell is not in OLC state. The downlink data transfer rate is 384 kbit/s, thecorresponding TF is 12 x 336, and TFS is {12 x 336, 8 x 336, 4 x 336, 2 x 336, 1 x 336,0 x 336}.336 is the TB size, 320 payload + 16 MAC headAt point A, the cell enters OLC state. The RNC selects this RAB to do fast TF restriction.MAC restricts the TFC selection during time between point A and point B by calculatingthe maximum TB number as follows:TFmax(1) = TFmax(0) x Ratelimitcoeff = 12 x 0.68 = 8.16Match 8.16 and the TFS. Therefore, the maximum TB number is 8.At point B, MAC performs further TFC restriction by calculating maximum TB number asfollows:TFmax(2) = TFmax(1) x Ratelimitcoeff = 8 x 0.68 = 5.44Match 5.44 and the TFS. Then, the maximum TB number is 4.At point C and point D, similar process is followed.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL/DL OLC fast TF restrict RAB numberParameter ID: UL/DLOLCFTFRSTRCTRABNUMThe default value of this parameter is 3UL/DL OLC fast TF restrict timesParameter ID: UL/DLOLCFTFRSTRCTTIMESThe default value of this parameter is 3Key parametersUL/DL OLC fast TF restrict RAB numberParameter ID: UL/DLOLCFTFRSTRCTRABNUMValue range: 0 to 10Content: These parameters specify the maximum number of RABs selected in a fastTF restriction of UL/DL OLC.If the number of RABs that fulfil the criteria for TF control is smaller than the value ofthis parameter, then all the RABs that fulfil the criteria are selected.The default value of this parameter is 3Set this parameter through ADD CELLOLC / MOD CELLOLCUL/DL OLC fast TF restrict timesParameter ID: UL/DLOLCFTFRSTRCTTIMESValue range: 0 to 100Content: These parameters specify the times of UL/DL OLC fast TF restrictions thatare executed.The default value of this parameter is 3Set this parameter through ADD CELLOLC / MOD CELLOLC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL TF rate restrict coefficientParameter ID: RateRstrctCoefThe default value of this parameter is 68%DL TF rate restrict timer lengthParameter ID: RateRstrctTimerLenThe default value of this parameter is 3000 (ms)Key parametersDL TF rate restrict coefficientParameter ID: RateRstrctCoefValue range: 1 to 99 %Content: This parameter specifies the data rate restriction coefficient in the fast TFrestriction. The smaller the parameter is, the more effective the TF restriction is. Afterreceiving the TF control indication, the MAC obtains the maximum TF format with theformula TFmax = TFmax x Ratelimitcoeff .The default value of this parameter is 68 %Set this parameter through ADD CELLOLC / MOD CELLOLCDL TF rate restrict timer lengthParameter ID: RateRstrctTimerLenValue range: 1 to 65535 msContent: This parameter specifies the length of the data rate restriction timer in the fastTF restriction. The smaller the value of this parameter is, the more effective the TFrestriction is.The default value of this parameter is 3000 msSet this parameter through ADD CELLOLC / MOD CELLOLC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.DL TF rate recover timer lengthParameter ID: RateRecoverTimerLenThe default value of this parameter is 5000 (ms)DL TF rate recover coefficientParameter ID: RecoverCoefThe default value of this parameter is 130 %Key parametersDL TF rate recover timer lengthParameter ID: RateRecoverTimerLenValue range: 1 to 65535 msContent: This parameter specifies the length of the data rate recovery timer. Thesmaller the value of this parameter is, the faster the BE traffic rate increases after thecongestion is resolved.The default value of this parameter is 5000 msSet this parameter through ADD CELLOLC / MOD CELLOLCDL TF rate recover coefficientParameter ID: RecoverCoefValue range: 100 to 200 %Content: This parameter specifies the data rate recovery coefficient in the fast TFrestriction. The larger the parameter is, the larger the TF recover effect. After receivingcongestion release indication, the MAC obtains the maximum TF format with theformula TFmax = TFmax x RateRecovercoeff.The default value of this parameter is 130%Set this parameter through ADD CELLOLC / MOD CELLOLC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.OLC ActionSwitching BE Services to Common ChannelTarget userBased on the user integrate priorityThe users with the DCH or HSDPA BE services in PSExecutionThe RNC sends “RB Reconfiguration” message to UEUE make a response by “RB Reconfiguration Complete”The OLC algorithm for switching BE services to common channel operates as follows:Based on the user integrate priority, the OLC sorts all UEs that only have PS servicesincluding HSPA and DCH services (except UEs having also a streaming bearer) into adescending order.The top N UEs are selected. The number of selected UEs is equal to Transfer CommonChannel user number. If UEs cannot be selected, the action fails. The OLC performs thenext action.The selected UEs are switched to common channel.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Transfer Common Channel User numberParameter ID: TransCchUserNumThe default value of this parameter is 1Key parametersTransfer Common Channel User numberParameter ID: TransCchUserNumValue range: 1 to 10Content: This parameter specifies the transfer common channel user numberThe default value of this parameter is 1Set this parameter through ADD CELLOLC / LST CELLOLC / MOD CELLOLC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.OLC ActionRelease of Some RABsTarget userBased on the RAB integrate priorityDCH services RABExecutionThe RNC sends “IU Release Request” message to CNThe RNC sends “RRC Connection Release” message to UEOLC Algorithm for the Release of Some RABs in the Uplink:The OLC algorithm for the release of some RABs in the uplink operates as follows:Based on the integrate priority, the OLC sorts all RABs including HSUPA and DCH servicesinto a descending order.The top RABs selected. If the integrate priorities of some RABs are identical, the RAB withhigher rate (current rate for DCH RAB and GBR for HSUPA RAB) in the uplink isselected. The number of selected RABs is equal to UL OLC traff release RAB number.The selected RABs are released directly.OLC Algorithm for the Release of Some RABs in the DownlinkThe OLC algorithm for the release of some RABs in the downlink operates as follows:Based on the integrate priority, the OLC sorts all RABs into a descending order.The top-priority RABs are selected. If the integrate priorities of some RABs are identical,the RAB with higher rate (current rate) The number of selected RABs is equal to DLOLC traff release RAB number.The selected RABs are directly released.
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.UL/DL OLC traff release RAB numberParameter ID: UL/DLOLCTRAFFRELRABNUMThe default value of this parameter is 0Key parametersUL/DL OLC traff release RAB numberParameter ID: UL/DLOLCTRAFFRELRABNUMValue range: 0 to 10Content: Either parameter specifies the number of RABs released in a UL or DL OLCrelease action.If the number of RABs that fulfil the criteria for release is smaller than the value of thisparameter, then all the RABs that fulfil the criteria are selected.The default value of this parameter is 0Set this parameter through ADD CELLOLC / MOD CELLOLC
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.SummaryLoad Control AlgorithmsPUC (Potential User Control)LDB (Intra-Frequency Load Balancing)CAC (Call Admission Control)IAC (Intelligent Admission Control)LDR (Load Reshuffling)OLC (Overload Control)
    • Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.Thank Youwww.huawei.com