Classify Parameter ProblemsMobile Management Parameter ProblemsPower Control Parameter ProblemsPower Configuration Parameter ProblemsLoad Control Parameter ProblemsOther Parameter Problems
Determine Parameter ValuesList Parameters Changing Form( Original Parameter Values vs. New Parameter Values)List Parameters Changing MML CommandNote : Maybe some Tradeoff considerations need taking into accountto assure the maximal improvement in the whole view such as“coverage and capacity”,“ fast and stable”, “improvement and risk” ,“cost (or efforts) and gain”, etc.
Evaluate Changing InfluenceEvaluate influence on Customer Service and Other NetworksEvaluate influence on OMC ( Efforts , Maintenance)
Prepare Test Plan and Implement ChangingPrepare Test schedule , Routes, Tools and be ready to getInformation .Change Parameters and Make Records.
Parameters Optimization ContentsMobile Management Parameters OptimizationPower Control Parameters OptimizationPower Configuration Parameters OptimizationLoad Control Parameters OptimizationNote: Because there are a lot of parameters , it is not possible to introduceevery parameter . Only some parameters about network optimization arementioned here and maybe more parameters need to be added in the future.
Mobile Management ParametersOptimization Cell Selection & ReselectionThe changing of cell on which UE camped in Idle mode or in Cell FACH ,Cell PCH ,URA PCH states. That assures UE camping the most suitable cell ,receiving system information and establishing a RRC connection on a bestserving cell. HandoverThe changing of cells with which UE connected in DCH mode.That assures seamless coverage and load balancing.
Cell Selection & Reselection ProcedureInitialCell SelectionAny CellSelectiongo herewhen noUSIM inthe UEUSIM insertedCamped onany cellgo here whenever anew PLMN isselected1no cell informationstored for the PLMNcell informationstored for the PLMNStoredinformationCell Selectionno suitable cell foundno suitablecell foundCell Selectionwhen leavingconnectedmodesuitable cell found 2suitablecell foundCampednormallysuitable cell foundno suitablecell foundleaveidle modereturn toidle modeConnectedmodeCellReselectionEvaluationProcesssuitablecell foundtriggerno suitablecell found1Cell Selectionwhen leavingconnectedmodeno acceptable cell foundacceptablecell foundacceptablecell foundsuitablecell found 2leaveidle modereturn toidle modeConnectedmode(Emergencycalls only)CellReselectionEvaluationProcessacceptablecell foundtriggerno acceptablecell foundNAS indicates thatregistration on selectedPLMN is rejected(except with cause #14or #15 )
Cell Selection Criteria (S Criteria)The cell selection criterion S is fulfilled when:for FDD cells: Srxlev > 0 AND Squal > 0for TDD cells: Srxlev > 0Where:Squal = Qqualmeas – QqualminSrxlev = Qrxlevmeas - Qrxlevmin - PcompensationWhen UE wants to select an UMTS cell , the cell should besatisfied with S Criterion.
Cell Re-selection Measure Condition use Squal for FDD cells and Srxlev for TDD for Sx 1. If Sx > Sintrasearch, UE need not perform intra-frequency measurements.If Sx <= Sintrasearch, perform intra-frequency measurements.If Sintrasearch, is not sent for serving cell, perform intra-frequency measurements. 2. If Sx > Sintersearch, UE need not perform inter-frequency measurements.If Sx <= Sintersearch, perform inter-frequency measurements.If Sintersearch, is not sent for serving cell, perform inter-frequency measurements. 3. If Sx > SsearchRAT m, UE need not perform measurements on cells ofRAT"m".If Sx <= SsearchRAT m, perform measurements on cells of RAT "m".If SsearchRAT m, is not sent for serving cell, perform measurements on cells ofRAT "m".
Cell Reselection Criteria (R Criteria) 1) All cells should be satisfied with S Criteria. 2) Select the Cell with the highest R value using the following method to compute.Rs = Qmeas,s + QhystsRn = Qmeas,n - Qoffsets,nThe cells shall be ranked according to the R criteria specified above, deriving Qmeas,n andQmeas,s and calculating the R values using CPICH RSCP, P-CCPCH RSCP and the averaged received signallevel for FDD, TDD and GSM cells, respectively.The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst1s is usedfor Qhysts to calculate Rs.If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICHEc/No, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above, butusing the measurement quantity CPICH Ec/No for deriving the Qmeas,n and Qmeas,s and calculating the R valuesof the FDD cells. The offset Qoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used forQhysts to calculate Rs.. Following this second ranking, the UE shall perform cell re-selection to the best rankedFDD cell.In all cases, the UE shall reselect the new cell, only if the following conditions are met:- the new cell is better ranked than the serving cell during a time interval Treselection.- more than 1 second has elapsed since the UE camped on the current serving cell.
Cell Reselection from GSM to UMTS If the 3G Cell Reselection list includes UTRAN frequencies, the MS shall, at least every 5 supdate the value RLA_C for the serving cell and each of the at least 6 strongest non-servingGSM cells. The MS shall then reselect a suitable (see TS 25.304) UTRAN cell if its measured RSCP valueexceeds the value of RLA_C for the serving cell and all of the suitable (see 3GPP TS 03.22) non-serving GSM cells by the value XXX_Qoffset for a period of 5 seconds and, for FDD, the UTRANcells measured Ec/No value is equal or greater than the value FDD_Qmin. In case of a cellreselection occurring within the previous 15 seconds, XXX_Qoffset is increased by 5 dB.where Ec/No and RSCP are the measured quantities. FDD_Qmin and XXX_Qoffset are broadcast on BCCH of the serving cell. XXX indicatesother radio access technology/mode.Note:The parameters required to determine if the UTRAN cell is suitable are broadcast onBCCH of the UTRAN cell. An MS may start reselection towards the UTRAN cell beforedecoding the BCCH of the UTRAN cell, leading to a short interruption of service if theUTRAN cell is not suitable. Cell reselection to UTRAN shall not occur within 5 seconds after the MS has reselected aGSM cell from an UTRAN cell if a suitable GSM cell can be found. If more than one UTRAN cell fulfils the above criteria, the MS shall select the cell with thegreatest RSCP value.
Soft Handover Event – 1A1A (Add a cell in Active Set))2/(10)1(1010 111aaBestNiiNewNew HRLogMWMLogWCIOLogMA−−⋅⋅−+⋅⋅≥+⋅ ∑=MNew : the measurement result of the cell entering the reporting range.CIONew : the individual cell offset for the cell entering the reporting rangeif an individual cell offset is stored for that cell. Otherwise it is equal to 0.Mi : measurement result of a cell not forbidden to affect reporting range inthe active set.NA : the number of cells not forbidden to affect reporting range in thecurrent active set.MBest : the measurement result of the cell not forbidden to affect reporting rangein the active set with the highest measurement result, not taking into accountany cell individual offset.W : a parameter sent from UTRAN to UE.R1a : the reporting range constant.H1a : the hysteresis parameter for the event 1a.
Soft Handover Event – 1B1B (Remove a cell from Active Set))2/(10)1(1010 111bbBestNiiOldOld HRLogMWMLogWCIOLogMA+−⋅⋅−+⋅⋅≤+⋅ ∑=MOld : the measurement result of the cell leaving the reporting range.CIOOld : the individual cell offset for the cell leaving the reporting range ifan individual cell offset is stored for that cell. Otherwise it is equal to 0.Mi : measurement result of a cell not forbidden to affect reporting range in theactive set.NA : the number of cells not forbidden to affect reporting range in the currentactive set.MBest : the measurement result of the cell not forbidden to affect reporting rangein the active set with the lowest measurement result, not taking into accountany cell individual offset.W : a parameter sent from UTRAN to UE.R1b : the reporting range constant.H1b : the hysteresis parameter for the event 1b.
Soft Handover Event – 1C 1C (A non-active primary CPICH becomes better than an activeprimary CPICH. If Active Set is not full ,add the non-active cell intoactive set .Otherwise use the cell substitute the active cell . )2/1010 1cInASInASNewNew HCIOLogMCIOLogM ++⋅≥+⋅MNew : the measurement result of the cell not included in the active set.CIONew : the individual cell offset for the cell becoming better than the cell in the activeset if an individual cell offset is stored for that cell. Otherwise it is equal to 0.MInAS : the measurement result of the cell in the active set with the highestmeasurement result.MInAS : the measurement result of the cell in the active set with the lowestmeasurement result.CIOInAS : the individual cell offset for the cell in the active set that is becoming worsethan the new cell.H1c : the hysteresis parameter for the event 1c.
Soft Handover Event – 1D1D (Change of best cell. If the chosen cell is not in Active Set ,add the cell into Active Set and modify measurement control.Otherwise only modify measurement control. )2/1010 1dBestBestNotBestNotBest HCIOLogMCIOLogM ++⋅≥+⋅MNotBest : the measurement result of a cell not stored in "best cell"CIONotBest : the cell individual offset of a cell not stored in "best cell" .MBest: the measurement result of the cell stored in "best cell".CIOBest : the cell individual offset of a cell stored in "best cell" .H1d : the hysteresis parameter for the event 1d.
Soft Handover ParametersParameter Name Description Default SettingIntraRelThdFor1A Relative thresholds of soft handover for Event 1A (R1a) 10 , namely 5dB (step 0.5)IntraRelThdFor1B Relative thresholds of soft handover for Event 1B (R1b) 10 , namely 5dB (step 0.5)Hystfor1A, Hystfor1B,Hystfor1C, Hystfor1DSoft handover hysteresis (H1x) 6,namely 3dB (step 0.5) for H1a .8,namely 4dB(step 0.5) for H1b,H1c,H1d.CellIndividalOffset Cell CPICH measured value offset; the sum of thisparameter value and the actually tested value is used forUE event estimation. (CIO)0WEIGHT Weighting factor, used to determine the relativethreshold of soft handover according to the measuredvalue of each cell in the active set.0TrigTime1A,TrigTime1B,TrigTime1C,TrigTime1DSoft handover time-to-trigger parameters (event time-to-trigger parameters. Only the equation are alwayssatisfied during the trigger time, the event will betriggered).D640, namely 640ms .FilterCoef Filter coefficient of L3 intra-frequencymeasurementD5 ,namely 5
Intersystem Handover Measure1) Use Inter-frequency measurement reporting Event 2D ,2Fto reflect the currently used frequency quality.Event 2d: The estimated quality of the currently used frequency is below a certain threshold. The variables in the formula are defined as follows: QUsed is the quality estimate of the used frequency. TUsed 2d is the absolute threshold that applies for the used frequency and event 2d. H2d is the hysteresis parameter for the event 2d.Event 2f: The estimated quality of the currently used frequency is above a certainthreshold. The variables in the formula are defined as follows: QUsed is the quality estimate of the used frequency. TUsed 2f is the absolute threshold that applies for the used frequency and event 2f. H2f is the hysteresis parameter for the event 2f.2/22 ddUsedUsed HTQ −≤2/22 ffUsedUsed HTQ +≥
Intersystem Handover Measure2 ） When Received 2D reports ( that means the currently used frequency signal is poor ) , RNCsends Measurement Control (ID3) to let UE begin to measure other system signal . UE willsend measurement result reports periodically . When Received 2F reports (that means thecurrently used frequency signal is not poor), RNC sends Measurement Control (ID3,butdifferent contents) to let UE stop measuring other system signal .3) When received the periodical reports , RNC use the following formula to judge whether shouldhandover UE to another system .Mother_RAT + CIO > Tother_RAT + H/2Tother_RAT : the inter-system handover decision threshold;Mother_RAT : the inter-system (GSM RSSI) measurement result received by RNC;CIO: Cell Individual Offset, which is the inter-system cell setting offset;H : refers to hysteresis,If the formula is met, a trigger-timer called TimeToTrigForSysHo will be started, and a handover decision will bemade when the timer times out;Note: if the inter-system quality satisfies the following condition before the timer times out:Mother_RAT + CIO < Tother_RAT - H/2The timer will be stopped, and RNC will go on waiting to receive the next inter-system measurement report.The length of the trigger-timer is called time-to-trigger.
Parameters Optimization ContentsMobile Management Parameters OptimizationPower Control Parameters OptimizationPower Configuration Parameters OptimizationLoad Control Parameters Optimization
Power Control Parameters OptimizationPower Control Characteristics Minimize the interference in the network, thus improvecapacity and quality Maintain the link quality in uplink and downlink by adjustingthe powers Mitigate the near far effect by providing minimum required powerlevel for each connection Provides protection against shadowing and fast fading
Power Control Classification Open Loop Power ControlOpen loop power control is used to determine UE’s initial uplink transmit power in PRACH andNodeB’s initial downlink transmit power in DPDCH. It is used to set initial power reference values forpower control. Outer Loop power controlOuter loop power control is used to maintain the quality of communication at the level of bearer service qualityrequirement, while using as low power as possible. Inner loop power control (also called fast closed loop power control)Inner loop power control is used to adjust UE’s uplink / NodeB’s downlink Dpch Power every one slot inaccordance with TPC commands. Inner loop power control frequency is 1500Hz.
Open Loop Power Control - UplinkBCH£ ºCPICH channel powerBCH£ ºCPICH channel powerUL interference leveUL interference leveConstant ValueConstant ValueMeasure CPICH_RSCPMeasure CPICH_RSCPand determine the initialand determine the initialtransmitted powertransmitted powerRACHRACHPreamble_Initial_Power = Primary CPICH TX power - CPICH_RSCP+ UL interference + Constant Valuewhere Primary CPICH TX power , UL interference and Constant Value are broadcastedin the System Information ， and CPICH_RSCP is the measured value by UE 。
Open Loop Power Control - DownlinkDCHDCHMeasure CPICH Ec/I0Measure CPICH Ec/I0RACH reports theRACH reports themeasured valuemeasured valueDetermine the downlink initial powerDetermine the downlink initial powercontrolcontrolwhere R is the user bit rate. W is the chip rate (3.84M).Pcpich is the Primary CPICH transmit power.Eb/Io is the downlink required Eb/Io value for a bearer service.(Ec/Io)cpich is measurement value reported by the UE.a is downlink cell orthogonal factor.Ptotal is the current cell’s carrier transmit power measured at the NodeBand reported to the RNC.))/(( totalocCPICHobPcpichIEPWRIEP ×−××= α
Outer Loop Power ControlSRNC DRNCSet SI RSet SI Rt ar gett ar getSet SI R t ar getSet SI R t ar getSet SI R t ar getSet SI R t ar getMacr o di ver si t yMacr o di ver si t ycombi ni ngcombi ni ngOuter loop control is used to setting SirTarget (Signal to Interference Ratio Target) for inner loop powercontrol. It is divided into uplink outer loop power control and downlink outer loop power control.The uplink outer loop power control is controlled by SRNC (serving RNC) for setting a target SIR for eachUE. This target SIR is updated according to the estimated uplink quality (Block Error Ratio/ Bit Error Ratio).If UE is not in DTX (Discontinuous Transmission)status (that means RNC can receive uplink traffic data),RNC will use Bler (Block Error Ratio) to compute SirTarget . Otherwise , RNC will use Ber (Bit Error Ratio)to compute SirTarget.The downlink outer loop power control is controlled by the UE receiver to converge to required link quality(BLER) set by the network (RNC) in downlink.
Inner Loop Power ControlThe inner-loop power control adjusts the UE or NodeBtransmit power in order to keep the receivedsignal to interference ratio (SIR) at a given SIR target,‑ ‑SIRtarget.It is also divided into uplink inner loop power control anddownlink inner loop power control.
Uplink Inner Loop Power Control UTRAN behaviourThe serving cells (cells in the active set) should estimate signal-to-interference ratioSIRest of the received uplink DPCH. The serving cells should then generate TPCcommands and transmit the commands once per slot according to the following rule: ifSIRest > SIRtarget then the TPC command to transmit is "0", while if SIRest < SIRtargetthen the TPC command to transmit is "1". UE behaviourUpon reception of one or more TPC commands in a slot, the UE shall derive a singleTPC command, TPC_cmd, for each slot, combining multiple TPC commands if morethan one is received in a slot. This is also valid when SSDT transmission is used in thedownlink. Two algorithms shall be supported by the UE for deriving a TPC_cmd. Whichof these two algorithms is used is determined by a UE-specific higher-layer parameter,"PowerControlAlgorithm", and is under the control of the UTRAN. If"PowerControlAlgorithm" indicates "algorithm1", then the layer 1 parameter PCA shalltake the value 1 and if "PowerControlAlgorithm" indicates "algorithm2" then PCA shalltake the value 2.
Uplink Inner Loop Power Control The step size DTPC is a layer 1 parameter which is derived from the UE-specifichigher-layer parameter "TPC-StepSize" which is under the control of the UTRAN. If"TPC-StepSize" has the value "dB1", then the layer 1 parameter DTPC shall take thevalue 1 dB and if "TPC-StepSize" has the value "dB2", then DTPC shall take the value2 dB. The parameter "TPC-StepSize" only applies to Algorithm 1 . For Algorithm 2 DTPCshall always take the value 1 dB. After deriving of the combined TPC command TPC_cmd using one of the two supportedalgorithms, the UE shall adjust the transmit power of the uplink DPCCH with a step ofDDPCCH (in dB) which is given by:DDPCCH = DTPC × TPC_cmd.
Uplink Inner Loop Power Control Algorithm 1 for processing TPC commandsWhen a UE is not in soft handover, only one TPC command will be received ineach slot. In this case, the value of TPC_cmd shall be derived as follows:- If the received TPC command is equal to 0 then TPC_cmd for that slot is –1.- If the received TPC command is equal to 1, then TPC_cmd for that slot is Algorithm 2 for processing TPC commandsWhen a UE is not in soft handover, only one TPC command will be received ineach slot. In this case, the UE shall process received TPC commands on a 5-slotcycle, where the sets of 5 slots shall be aligned to the frame boundaries and thereshall be no overlap between each set of 5 slots.The value of TPC_cmd shall be derived as follows:- For the first 4 slots of a set, TPC_cmd = 0.- For the fifth slot of a set, the UE uses hard decisions on each of the 5received TPC commands as follows: - If all 5 hard decisions within a set are 1 then TPC_cmd = 1 in the 5th slot. - If all 5 hard decisions within a set are 0 then TPC_cmd = -1 in the 5th slot. - Otherwise, TPC_cmd = 0 in the 5th slot.
Downlink Inner Loop Power ControlUE behaviourThe UE shall generate TPC commands to control the network transmit powerand send them in the TPC field of the uplink DPCCH. The UE shall checkthe downlink power control mode (DPC_MODE) before generatingthe TPC command: - if DPC_MODE = 0 : the UE sends a unique TPC command in each slot and theTPC command generated is transmitted in the first available TPC field in the uplinkDPCCH; - if DPC_MODE = 1 : the UE repeats the same TPC command over 3 slots andthe new TPC command is transmitted such that there is a new command at thebeginning of the frame.The DPC_MODE parameter is a UE specific parameter controlled by theUTRAN.
Downlink Inner Loop Power ControlUTRAN behaviourUpon receiving the TPC commands UTRAN shall adjust its downlink DPCCH/DPDCHpower accordingly. For DPC_MODE = 0, UTRAN shall estimate the transmitted TPCcommand TPCest to be 0 or 1, and shall update the power every slot. If DPC_MODE =1, UTRAN shall estimate the transmitted TPC command TPCest over three slots to be 0or 1, and shall update the power every three slots.
Common Channels ParametersAll channels’ power is reference to PCPICH Power expect PCPICH itself .
Dedicated Channels ParametersDedicated Channel Power is also reference to PCPICH Power.
Parameters Optimization ContentsMobile Management Parameters OptimizationPower Control Parameters OptimizationPower Configuration Parameters OptimizationLoad Control Parameters Optimization
Load Control Parameters OptimizationCall Admission Control (CAC)Call admission control is used to control cell’s load byadmission/rejection request to assure a cell’s load under control. Dynamic Channel Configuration Control (DCCC)Dynamic Channel Configuration Control is used to dynamicallychange a connection’s load to improve cell resource utilization andcontrol cell’s load.
Call Admission Control ParametersDifferent service type can be configured different threshold. That means leave someresources for important service ( or request), such as HO > Conversation > Other.Ul(Dl)TotolKThd is used when NodeB load report is not available . It uses equivalent12.2k _voice users number method.
Dynamic Channel Configuration Control DCCC: Dynamic Channel Configuration Control aim to making full useof radio resource (codes, power, CE )- Configured bandwidth is fixed when no DCCC- Configured bandwidth is changing when DCCC- Traffic rateRateorband
DCCC ProcedureMeasurement reportMeasurement reportDCCC decisionDCCC decisionTraffic Volumemeasurement controlTraffic Volumemeasurement controlUE and RNC MeasurementUE and RNC MeasurementDCCC executionDCCC execution
SummaryParameter Optimization improves network quality and solvesnetwork problems.Parameter Optimization is a complicated procedure andneeds parameter and algorithm knowledge.Parameter Optimization will be combined with otheroptimization activities making network better !
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