Genuine Call Setup Failure Scenarios– RF issue • Interference / Dominance / Coverage • Missing neighbour– System Issue - BTS • No response to “RRC Connection Request” • “RRC Connection Reject” to “RRC Connection Request”– System issue - RNC • “CC Disconnect” after “Call Proceeding” due to “DL RRC Connection Release”– Core NW • “CM Service Abort” after “CM Service Request”– System issue (test number) • “CC Disconnect” after “CC Progress”
Genuine Drop Call scenariosRF issue – Interference / Dominance / Coverage – Missing NeighboursSystem issue BTS – Sudden “CC Disconnect” due to “DL RRC Connection Release” – Sudden drop to idle, no disconnect messagingSystem issue RNC – Sudden “CC Disconnect” due to “DL RRC Connection Release”
KPI DefinitionsThe KPIs to be monitored from the RAN could be: – Cell availability – Call Setup Success Rate (CSSR) – Call Drop rate – SHO/ISHO/HSPA SCC success rate – Packet Session setup/success rate (NRT, HSDPA, HSUPA)In NOLS: – RNC counter description – NetAct DB description for RNC measurements – WCDMA RAN Key Performance Indicators – Key Indicator Changes – Measurement Changes Presentation / Author / Date
AMR CS Call PhasesUE WBTS DRNC SRNC CN 1. Cell search, BCCH decoding & RACH access 2. RRC connection set-up 3. UE <--> CS-CN signalling 4. RAB set-up 5. UE <--> CS-CN Signalling 6. Service Established 7. Branch addition/deletion & Active set update 8. Service Released
Call Setup Failure StartAnalysis A Coverage Optimization Best server’s NoProcess__DT RSCP > -102dBm No Missing Dominance Optimization Yes Neighbour ? Best server’s No Yes Neighbour list Optimization Ec/No > -12dB Yes UL coverage & RACHB parameter. Optimization (changing serving cell) No AICH(ACK) received? Report & Finish (Check failure cause) Yes No “RRC Connection Setup” received? No “RRC Setup Reject” received? C Yes Yes AC optimization (check PrxNoiseD Report & Finish (Reason of problem: L1 sync fail) No (DCH) “RRC Connection setup Completed” sent from UE? & interferer around BTS) Report & Finish Yes Report & Finish No “Radio Bearer setup (Check failure cause) failure”Received? Ye s E Report & Finish Check failure cause (Not radio problem/cell update)
Call setup failures – Missing A NeighbourMissing neighbour analysis over the whole route (3G-3G, 3G-2G)Search for failures due to missing 3G-3G neighboursSearch for failures due to missing 3G –2G neighbours – It is suggested to place 2G scanner to the test vehicle
Call Setup Failure Analysis- Block B B -The purpose of this activity is to check the Random Access Process is working adequately by investigating whether AI (Acquisition Indicator) has been received through DL AICHIf AICH was not received by UE, the cause of the problem can be classified into: – Inadequate RAN parameter related to Random Access: RAN parameter settings for pre-amble transmission or open loop power control information is not correct.
Call Setup Failure Analysis- Block B B UE - WBTS RNC Preamble/RACH Acquisition Indicator/AICH RRC: RRC Connection Request/PRACH NBAP: RADIO LINK SETUP REQUEST NBAP: RADIO LINK SETUP RESPONSE RRC: RRC CONNECTION SETUP/FACH L1 Synchronisation NBAP: SYNCHRONISATION INDICATOR RRC: RRC CONNECTION SETUP COMPLETE/DCH UE in CELL_DCH state
RACH Process B L1 ACK / AICHDownlink Not detectedBS UEtxPowerMaxPRACHPowerRampStepPRACHpreamble …… ……UplinkMS Preamble Preamble Message part 1 2 PowerOffsetLastPreamblePRACHmessage PRACH_preamble_retrans # PRACH preambles transmitted during one PRACH cycle without receiving AICH response RACH_tx_Max # preamble power ramping cycles that can be done before RACH transmission failure is reported Initial preample power: •Ptx = CPICHtransmissionPower-RSCP(CPICH) +RSSI(BS) + PRACHRequiredReceivedCI
Call Setup Failure Analysis- B Block B-Solutions for RACH optimisation PRACH_Preamble_retrans Max UE Tx power hit No To increase the UE_P_MAX(24dBm)? Or PowerRampStepPRACHPreamble Yes Yes Is UL Interference Report there might be an interfering abnormally HIGH? source Nearby the serving cell NoChange the Serving cell to cover the problem Area=> UE is too far to reach the serving cell
BCall Setup Failure Analysis- Block B Open loop Power Control parameters from RACH Info message
Call setup failures – System issue CNo response to “RRC Connection Request”BTS – Good RF conditions – Wrong MHA settings or cable loss settings can cause the site not to “hear” the UE – PrxNoise statistics, receive link parameters and HW units to be checked (faulty MHA, wrong MHA parameters, wrong cable / feeder loss parameters, faulty units)
Call setup failures – System issue C BTS “RRC Connection“RRC Connection Reject” after Request” – Good RF conditions – Admission Control can reject too many (or admit too many) connection requests due to wrong PrxNoise measurements. – PrxNoise statistics, receive link parameters and HW units to be checked
Call Setup Failure Analysis CUE has the appropriate DL/UL coverage but if RNC does not allow to set up the RRC connection of the requested RAB (Radio Access Bearer), Call setup will fail.Admission Control (AC) is involved in RRC connection setup. AC can reject RRC reject RRC connection Setup due the DL Load, UL load or DL Spreading codes – Marginal Load Area: • If measured UL (PrxTotal) or DL (PtxTotal) load exceeds target thresholds (PrxTarget and PtxTarget) AC can still admit new RAB to the cell if a new non-controllable load keeps below target thresholds (in practice this means that AC can admit only new controllable load RABs i.e. NRT RABs) – Overload Area: • If measured UL (PrxTotal) or DL (PtxTotal) load exceeds overload thresholds (PrxTarget + PrxOffset and PtxTarget + PtxOffset) then AC cant admit more RABs to the cell
Call Setup Failure Analysis C• During the pre-optimization phase it is unlikely that AC will stop an RRC connection setup during the drive testing because there are normally very few UEs in the network. (Traffic loading is trivial)• However, it should be checked that measured PtxTotal and PrxTotal are less than PtxTarget (e.g. 40dBm) and PrxTarget (e.g. 4dB, 60% loading) respectively. • If DL AC does not allow RRC setup check the Tx power of WBTS, # of channels transmitted, Signaling messages. • If UL AC does not allow RRC setup: Check out if there is an interfering source nearby the serving cell.
Call Setup Failure Analysis DTo check if Layer 1 Synchronization (slot/frame sync) has failedIf “RRC Connection Setup” was received by UE but UE does not send “RRC Connection Setup Completed”, we will report “L1 synchronization failure” and have to check L1 system messages.
Call setup failures – System issue E• “CC Disconnect” after RNC “Call Proceeding”• Good RF conditions• Failures in RAB setup occur between the “RAB Assignment Request” being received from Core Network and the RAN sending out Radio Bearer Setup. Therefore the failure is between BTS and Core Network.
Call setup failures – System issue E“CC Disconnect” after “Call RNCProceeding” (cont.)An example (site shows highvalues on counter“RAB_STP_FAIL_CS_VOICE_BTS” during the drive testIn the recent check thecounter showed no failures.
Call setup failures – Core NW E“CM Service Abort” after “CM Service Request”Good RF conditions“Security Mode Command”- message not received by UE, thus the failure is believed to be at Core Network. UE Node B R C N M W G R CC R onnection Establishment Initial Direct Transfer (C S M ervice Request) S C :C C P onnection Request S C :C C P onnection C onfirm Location Reporting Control C m ID om on Security Mode C m om and • R C Initial D R : irect Transfer message is sent using acknowledged mode R to the C core LC S dom R ain. outing is to be based upon the local P-TM I S • The N S m A essage is not read by the R C but is forw N arded to the multimedia gatew The N S ay. A message includes the IM as a U identity SI E • The SC P: C C onnection Request message establishes the connection orientated signalling link in the sam w as it w for the R C connection phase.This does not reserve any resources for the e ay as R A R call itself. M • The Connection Confirmmessage identifies the R C w a destination local reference which is the N ith sam as the source reference w e ithin the Connection Request message • The Connection Confirmmessage identifies the C core w a source local reference S ith • The C core sends a R N P: Location R S A A eporting Control message to the R C requesting N information regarding the location of a particular UE • The R N P: C m IDm A A om on essage specifies the IM belonging to the U SI E • The S ecurity Mode C m om andmessage triggers the start or stop of ciphering and integrity protection.
Call setup failures – System Issue E (test number)“CC Disconnect” after “CC Progress”Cause: recovery on timer expiryThe call goes via IN SCP to a recording.A static test was done by Nokia Customer Care and in few instances the call dropped after 30 seconds of recording passed. Hence the problem is associated with the test number not the RAN 30 sec Cause: recovery on timer expiry
State Transition triggers Phys. Reconfiguration After RT call with inactive Frequent cell updates PS RABs Phys. Reconfiguration Fast call setup from URA Update, UL data, Paging UTRA RRC Connected Mode CELL_PCH URA_PCH CELL_PCH Fast call setup from URA_PCH Phys. Reconfiguration UL/DL activation timerAfter RT call with inactive PS RABs & high mobility in CELL_DCH CELL_FACH Phys. Reconfiguration CELL_DCH Cell Update, UL data, paging RB. Reconfiguration Traffic Volume, RACH load RRC Setup / Release RB. Reconfiguration Inactivity Timer, Overload IDLE Mode
State Transition triggers IDLE Call Setup 1.2 sec DCH Transition DCH-FACH due to inactivity 10 sec )Parameter) FACH Transition FACH-PCH due to inactivity 2 sec PCH )Parameter) FACH DCH Wake up time PCH – DCH due to activity 3 sec IDLE
Cell Availability RNC_183c Cell Availability KPI counts Cell availability from user point of view: 100 WO * _ IN sum AVAIL WCEL __ _STA Cell _ ty Availabili sum _ AVAIL _ EXIS WCEL _IN _ _ RNW DBM1000C178 AVAILABILITY WCELL IN WORKING STATE• # of samples when WCELL is in WO State. Counter M1000C180 is always updated along with this counter• Counter is updated with the value 1 once in approx. 5 seconds when the WCELL is in WO StateM1000C180 AVAILABILITY WCELL EXIST IN RNW DATABASE• # of samples when WCELL is configured in the database. This counter is used as a denominator for cellavailability calculation• Counter is updated with the value 1 one in approx. 5 seconds when the WCELL is configured in the radionetwork database Presentation / Author / Date
Cell Availability – There is also Optional Cell availability KPI, which counts Cell Availability from network point of view. Situation where WCELL is blocked by User are excluded from the formula. – RNC_727a Cell Availability KPI, excluding blocked by user state (BLU), Counts Cell availability from* point of view: WO network _ IN 100 _ sum AVAI WCE _ ST_ Cell state _ ty Availabili __ excluding BLU _ AVAIL _ EXI WCE _ _ _ _ IN RN D sum AVAIL _ BLO WCE _ _ BY _UM1000C179 AVAILABILITY WCELL BLOCKED BY USER• # of samples when WCELL is BLU State. Counter M1000C180 is always updated along with this counter• Counter is updated with the value 1 once in approx. 5 seconds when the WCELL is in BLU state Presentation / Author / Date
Low in CSSR? Identify call setup failure phasesSetup Phases Call CSSR affected if any of the followings take place. 1. RRC Conn. Setup Fail 2. RRC Conn. Access Fail 3. RAB Setup Fail 4. RAB Setup Access Fail Call Setup Success Call Drop Call Setup Phase ConnectedRRC RRC RRC RRC RAB Setup RAB DropConn. Req Conn. Setup Conn. Acc Conn. Act DNO Optimization Processes / JC Ejarque
Low in CSSR? RRC/RAB Setup & Access Analysis Process Flow Chart Top (N) RRCSetup and Access failures Top (N) RAB Setup and Access failures Setup FailureCell and Neighbour Cause? setup Cells availability Sites OK ? Setup Alarms/Tickets /Access RNC Troubleshooting Yes BTS/TRANS/FROZBS setup AC UL/DL Setup Interference Access /Access (DL codes) Capacity Optimisation Access Yes 3G cell at SRNS Relocation inter-RNC troubleshooting border ? NO Interference Coverage/Interf RF Optimisation erence Coverage DNO Optimization Processes / JC Ejarque
Call Setup Success Rate (CSSR)Poor CSSR could be a result of – Poor coverage or dominance or interference issues in Radio interface – Capacity issues in Radio or Iub interface – Configuration issues in WBTS (parameters or HW)CSSR is essentially RRC Setup Success * RAB Setup Success (or successful PS session setups in case of PS call)CSSR covers all the steps from the initial RRC connection request from the UE to the network, through the RRC setup phase and the RAB setup phase, and until user data is starting to get transferred.The CSSR formulas are for different traffic classes like: – CS voice calls (RNC 565 f) – CS video calls (RNC 566e) – PS RT Streaming Calls (RNC 575 d) – PS NRT Calls (Interactive & Background) (RNC 576d) Presentation / Author / Date
Definition of Call Set-Up Success UE Rate (CSSR) RRC: Connection Request BTS RNC CN RRC Connection Setup phase Resource Reservation in RNC, BTS, Transmission RRC: RRC Connection Request Setup RRC Connection Access phase RNC waits reply from UE RRC: RRC Connection CompletedRRC: Initial Direct Transfer cm service request RANAP: Initial UE Message DIRECT TRANSFER (Call Call Set- Proceeding) up RANAP: RAB Assignment Success Request RAB Connection Setup phase Rate Resource Reservation in RNC, BTS, Transmission Call Set- RRC: Radio Bearer Set-up up Time RAB Connection Access phase RNC waits reply from UE RRC: Radio Bearer Setup Complete RANAP: RAB Assignment DIRECT TRANSFER (Alerting) Response DIRECT TRANSFER (Connect) DIRECT TRANSFER (Connect Acknowledge) Presentation / Author / Date
RRC Connection Setup & Access UE and Active BTS RNC CN RRC: RRC connection Request RRC SETUP fails if some of the needed resources (RNC, BTS, AIR, RRC SETUP phase Transport) are not available. When an RRC setup failure occurs the RNC sends an RRC: RRC CONNECTION REJECT message to UERRC Setup time (Resource Reservation in RNC, BTS, Transport) RRC: RRC connection Setup RRC ACCESS fails if the UE does not reply to RRC: RRC RRC ACCESS phase CONNECTION SETUP message with the RRC: RRC CONNECTION (RNC waits for Reply from UE) SETUP COMPLETE message in given time, if the BTS reports a radio RRC: RRC connection Setup Complete link synchronisation failure or in an RNC internal failure occurs RRC ACTIVE phase RRC: Initial Direct Transfer RRC ACTIVE fails when an interface related (Iu, Iur , Iub, or Radio) or RNC internal failure occurs, and the failure causes the release of the RANAP: Initial UE Message RRC Connection. When an RRC active failure occurs, the RRC send a RANAP: IU RELEASE REQUEST to all involved CNs and waits for UE-CN Signalling RANAP: IU RELEASE COMMAND message (s) (E.g. RAB Establishment and Release) RANAP: Iu Release Command RRC: RRC connection Release RRC ACTIVE release cause can be either RRC: RRC connection Release Complete ISHO, IFHO, SRSN relocation or pre-emption Release RRC resources in RNC, BTS, Transport Presentation / Author / Date
RAB Access failures are not so Common UE RAB Setup & Access and Active BTS RNC CN RAB SETUP fails if some of the needed resources (RNC, BTS, AIR, Transport) are not available. When an RAB setup failure occurs the RRC Connection Active Phase, UE-CN Signalling RNC sends a RANAP: RAB ASSINGMENT RESPONSE message to RANAP: RAB Assignment Request the CN with an appropriate failure cause RAB SETUP phaseRAB Setup time (Resource Reservation in RNC, BTS, Transport) RAB ACCESS fails if the UE replies with an RRC: RADIO BEARER RRC: Radio Bearer Setup SETUP FAILURE message or the connection cannot be established in a RAB ACCESS phase give time. When a RAB access failure occurs, the RNC sends a (RNC waits for Reply from UE) RANAP: RAB ASSINGMENT RESPONSE message to the CN with an appropriate failure cause. Immediately after this, the RNC sends also a RRC: RB Setup Complete RANAP: IU RELEASE REQUEST to the CN and waits for RANAP: IU RANAP: RAB Assignment Response RELEASE COMMAND message RAB ACTIVE phase (User Plane Data Transfer) RANAP: RAB Assignment Request with IE: RAB reconfiguration RAB ACTIVE fails when an interface related (Iu, Iur, Iub, or Radio) or RAB Holding Time RNC internal failure occurs, and the failure causes the release of the RAB Reconfiguration Actions RAB connection. (Reconfigure RAB resources in RNC, BTS, Transport) RRC: RB Reconfiguration • If the UE has more than one RAB connection and the failure is not so RRC: RB Reconfiguration Complete critical that it would lease to an RRC Connection drop, only the failed RAB connection is released. The RNC sends a RANAP: RAB RANAP: RAB Assignment Response RELEASE REQUEST message to the CN and waits for a RANAP: RAB RANAP: RAB Assignment Request with IE: RAB Release RELEASE COMMAND or RANAP: IU RELASE COMMAND from CN RRC: Radio Bearer Release • Otherwise, both the RRC connection and RAB connection (s) are RRC: Radio Bearer Release Complete released. The RNC send a RANAP: IU RELASE REQUEST message to RANAP: RAB Assignment Response the CN and waits for a RANAP: IU RELEASE COMMAND MESSAGE from the CN Release RAB resources in RNC, BTS, Transmission Presentation / Author / Date
RRC connection set up failure RRC Connection is rejected ICSU can not process the callprocessing power on ICSU unitoming call request can not be handled due to lack of ICSU processing hand free” is RNC internal clear code. UE BS RNC RRC Connection Request ICSU overload RRC Connection Reject Cause: congestion Failure Counter M1001C618
Call Setup Failures RRC and RAB phases RRC connection setup RAN resources are reserved for signaling connection between UE and RNCPhase: Setup Access Active RRC access Connection between UE and RRC RRC active Active UE has RRC connection. If Success dropped, also active RAB is Setup Access Complete dropped. Complete Complete Access RAB setup Active Attempts to start the call Release RAB setup access Attempts RRC RAB active phase Active UE has RAB connection Drop Failures CSSR affected if any of the followings take Access failures place. • RRC Conn. Setup Fail • RRC Conn. Access Fail Setup failures • RAB Setup Fail (blocking) • RAB Setup Access Fail Presentation / Author / Date
Call Setup Success Rate (CSSR)CSSR KPI for CS voice from end user perspective (RNC 565f) 100 _ * ( ( MOC _ sum CONV _CALL CONV ATTS _ _ MOC FAILS _ CALL MTC _ _ CONV _CALL CONV ATTS _ _ MTC _ CALL FAILS EMERGENCY FAILS _ _ CALL ATTS _ _ EMERGENCY CALL RRC _ _ _ EMERGENCY ACC REL RRC _ _ _ _ MO ACC CONV REL RRC _ _ _ _ MT ACC CONV REL ) ( ( _ _ sum COMP RAB _ _ ACC VOICE CS ) AMR _ CSSR * sum ( _ MOC _ CONV _CALL CONV ATTS _ _ MTC _ CALL ATTS sum _ _ _ ( _ ATT )) RAB CS STP VOICE EMERGENCY _ _ _ CALL ATT CONV ATTS REP RRC _ _ _ MO RRC _ _ _ _ MT RRC _ ATT CONV REP _ _ EMERGENCY ATT REP RRC _ _ _ EMERGENCY ACC REL RRC _ _ _ _ MO ACC CONV REL RRC RRC _ _ _ _ MT RRC _ _ ACC CONV REL _ CONN _ REJ CALL STPEMERG _ ) RAB part partRRC request repetitions done by UE after RRC reject are excluded from denominator (not necessarily seen as failures from the users perspective) – Emergency calls re-directed to GSM layer are excluded from denominatorThe occurred cell re-selections are subtracted both from the numerator and denominator because they are not considered as call attempts from mobile end-user point of view. The UE has made a new RRC connection via another cell and Attempts-counter is Presentation / Author / Date updated in the new cell for the new attempt.
PS Call Setup Success Rate (CSSR) RNC_576d- Packet Call Setup Success Ratio [%] over the reporting period. Includes both Interactive and Background PS calls 100( *( MOC_ sum_ INTER CALLMOC_ _ATTS INTER _ CALL _FAILS MOC _ _BACKG CALLMOC _ _ ATTS BACKG _ CALL _FAILS MTC _ _INTER CALLMTC _ _ATTSINTER _ CALL _FAILS MTC _ _BACKG CALLMTC _ _ATTSBACKG _ CALL _FAILS EMERGENCY _CALLEMERGENCY _ATTS _CALL _FAILS RRC REL RRC REL BACKG ( _ _ACC INTER _ _ _ _ _ _ACC MO ( RAB_ sum ACC _ _ COMPPS INTER RRC REL INTER _ _ _ _ACC MO _ _ _ RRC REL BACKG _ACC MT ) RAB_ _ACC _ _ COMP ) PSBACKG PS _ CSSR * sum_ ( MOC_INTER CALLMOC _ _ATTS BACKG _ CALL _ATTSsum STP_ _ ( _ _ RAB ATTINTER PS MTC _ _INTER CALLMTC _ _ATTS BACKG _ CALL _ATTS RAB ATTBACKG _ _ _ _ STP PS )) RRC REP RRC REP INTER _ _ _ ATT INTER _ _ _ _ATT MO RRC REP BACKG_ _ _ _ _ _ _ ATT MO RRC REPBACKG _ATT MT RRC REL RRC REL BACKG _ACC INTER _ _ _ _ _ _ACC MORRC RRC REL INTER _ _ _ _ACC MO _ _ _ RRC REL BACKG _ACC MT )) RABpart part RRC request repetitions done by UE after RRC reject are included in the formula * The occurred cell re-selections are subtracted both from the numerator and denominator because they are not considered as call attempts from mobile end-user point of view. The UE has made a new RRC connection via another cell and Attempts-counter is updated in the new cell for the new attempt. Presentation / Author / Date
Low in CSSR: Failure Counters RRC Conn Setup & Access AnalysisRRC_CONN_STP_FAIL_AC Check UL Interference, DL Power & Code occupancy if there is need to upgrade radio capacityRRC_CONN_STP_FAIL_BTS Evaluate NBAP counters (radio link reconf. Failures) and KPIs for troubleshooting BTS resources Check BTS configuration in terms of CE allocation – Use Channel Element (5001) Counters in order to evaluate lack of Channel Elements Expand the Capacity or decrease the traffic offered to the site until the problem is solved In case BTS is not responding delete and re-create COCORRC_CONN_STP_FAIL_TRANS Evaluate Number of reconfiguration failure due the transmission Check COCO Configuration Expand the capacity or decrease the traffic offered to the site until the problem is solvedRRC_CONN_STP_FAIL_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care departmentRRC_CONN_STP_FAIL_RNTI ALLO FAIL RNC decides to reject RRC connection request due to RNTI allocation failure caused by RRMU overload DNO Optimization Processes / JC Ejarque
Low in CSSR: Failure Counters RRC Conn Setup & Access AnalysisRRC_CONN_STP_FAIL_IUB_AAL2_TRANS Updated when there is shortage or blocking of AAL2 resource A subset of RRC_CONN_FAIL_TRANS which include ERQ/ECF fail due to some reason such as DMPG problem in RNC + ERQ/ECF fail due to transport resource needed in RNC between RNC/MGWRRC_CONN_ACC_FAIL_RADIO Dominant failure causes due to wrong UL or DL coverage UL Coverage -> Check if cell is affected by an external interference (Thermal Noise measurements). DL Coverage -> Tune SCCPCH Power if UE does not receive the RRC Setup Message -> If UE does not synchronize, reduce N312 from 2 to 1 (depends on UE model) or tune CPICHToRefRABOffset vs. Qqualmin (or Qrxlevmin)RRC_CONN_ACC_FAIL_MS UL Coverage -> Tune Cell Dominance (or CPICH) in order to balance UL and DL (if UL interference if not the cause). Check if cell is affected by an external interference (Thermal Noise measurements). DNO Optimization Processes / JC Ejarque
Low in CSSR: Failure Counters RAB setup & Access Fail Root Cause Analysis: RT and NRT (I/B) domainsRAB_STP_FAIL_XXX_AC Check UL Interference, DL Power & Code occupancy if there is need to upgrade radio capacity using the alreadydistributed Nokia Capacity Check BO report. Check PrxTarget / PrxOffset / of the affected cellsRAB_STP_FAIL_XXX_BTS Evaluate NBAP counters (radio link reconf. Add failures) and KPIs for troubleshooting BTS resources Check BTS configuration in terms of CE allocation – Use Channel Element (5001) Counters in order to evaluate lack of Channel Elements Expand the Capacity or decrease the traffic offered to the site until the problem is solved. In case BTS is not responding delete and re-create COCORAB_STP_FAIL_XXX_TRANS Evaluate Number of reconfiguration failure due the transmission Check M1005C128 CANC_ADD_SRNC_TRAN_STP_FAIL Check RAB_STP_FAIL_XXX_IUB_AAL2, M1001C531-C533 Check COCO ConfigurationRAB_STP_FAIL_XXX_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care department DNO Optimization Processes / JC Ejarque
Low in CSSR: Failure Counters RAB setup & Access Fail Root Cause Analysis: RT and NRT (I/B) domainsRAB_ACC_FAIL_XXX_UE Evaluate Cell resource Prx and Ptx parameters (same as RAB_STP_FAIL_XXX_AC Case)RAB_ACC_FAIL_XXX_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care department. DNO Optimization Processes / JC Ejarque
High in DCR?Top (N) drops Neighbours’ Performance Traffic (use SHO success per adjs counters to identify badly Cell and its Neighbour performing neighbours) & Map Cells availability Site OK ? Alarms/Tickets Audit adjacent sites for alarms, Availability, configuration and capacity YES NO Configuration & Parameter audit Conf OK ? 3G Cell at Iur YES Investigation Iur RNC border? performance YES SHO YES SHO Success Rate < 90%? NO New site ? ISHO ISHO NO Analyse last detailed radio RF and IF/IS HO neighbour Failures measurements optimisation YES 3G cell 3G cell at covers over a To inter-RNC coverage p border ? hole ? iss No cell YES ue RF and ISHO neighbour found ratio s optimisation >40 % Core: Inners / Outers audit NO No cell found 2G : TCH blocking ratio > 90 % ISHO Coverage issue (new site3G : Wrong N’ borgs YES and enough needed) Success definition ADJG Rate < 95% DNO Optimization Processes / JC Ejarque
Call drop analysis process Start SHO Failure Yes SHO Failed Analysis No ISHO Yes Failure ISHO Failed Analysis No No Best server’s No Coverage Optimization RSCP> -102dBm Missing No Dominance Optimization Neighbour Best server’s Ec/No> -12dB Yes Neighbour listB Investigate possible BTS or RNC A Optimization problem Presentation / Author / Date
Call Drop Analysis process – SHO Start Check Iur Analysis Yes Inter RNC HO Check neighbor definition parameters No Yes No DL ASU Fix SC Clash SC Clash received C No YesLoad Yes Congestion No UE TxOptimisation on target cell Check RF Levels Power Max No Yes DL Tx No Load Optimisation/ Uplink Yes Power Max Interference External Interferer Yes No D CPICH Optimisation Link Yes Unbalanced No Presentation / Author / Date
A Drop call failures – RF issueRF drops mostly due to poordominance or interferencePoor coverage could lead to ISHO,although poor dominance orinterference can cause ISHO to fail.Rapid field drop can cause drop dueto coveragePoor dominance or interference cancause Compressed Mode (CM) tostart even if RSCP is still good.In CM UE transmits with higherpower (more interference) andspends less time on 3G (lessaccurate measurement reporting)Poor dominance or interference canlead to Active Set update failures Poor dominanceand eventually to drop call. causes Active Set update failures Presentation / Author / Date
A Drop call failures – RF issueDL synchronisation is lost ->UE has stopped transmitting TrChAgg and DL DPCCH BER high Presentation / Author / Date
ADrop call failures – RF issue Fairly good CPICH Pilot EcNo Transport Channel BER. Btw UE<- >RNC (MAC layer) Sometimes DPCCH BER (btw UE<->WBTS) can be a better indicator of whats happening to the dedicated channel than the CPICH EcNo, in particular in the case that power control may not be tracking well Presentation / Author / Date
Drop Call Failures – System issue B BTSSudden drop to idle, no disconnect messaging – Site malfunctions to be checked – In the example below site had faulty unit (WTR) Drop to IDLE Presentation / Author / Date
Drop Call Failures – System Issues B“CC Disconnect” due to RNC DPCCH BER“DL RRC ConnectionRelease”No response to ULMeasurement ReportsIn the example site had noalarms, good RF & BERNot able to add SC265 toActive Set, next call on thesame cell => no failure.Difficult to troubleshoot ifthe failure does nothappen systematically =>follow up in the nextweeks drive / do aseparate drive test in the Sudden “RRCarea Connection Release” Presentation / Author / Date
C Drop call failures (SC conflict)Sudden drop to idle Transportmode (no disconnect channelmessaging) BLER 100%Cause of the failure:overshooting site andSC reuseShort term solution toadd overshootingneighbour in ADJSdefinitions Cell ABC, SC258 Presentation / Author / Date
Drop call failures – Uplink D Interference UL interference from the SIB7 message Presentation / Author / Date
D Drop call failures – Link BalanceUL & DL Power Control commands can UE RX power controlhelp indicating problems in link balance. message: DL reception weak -> UE is orderingPC frequency is 1500 Hz, thus ideally the WBTS to increase power.sum of PC commands to increase ordecrease power is 1500E.g. if the sum of UL PC commands is <1500, this would indicate UE is starting toloose synchronizationin Compressed Mode there is less PCcommands, UE spends time on 2G Sum of UL PC commands < 1500, UE not receiving all the PC commands. Presentation / Author / Date
Drop call failures – System issue RNC or BTS ?“CC Disconnect” due to “DL RRC Connection Release” is just a consequence offailure which can be due to different reasons – From UE point of view L3-messaging does not identify the point of failure distinctly – BTS or RNC failure? => Suspect BTS first, then RNCRule out BTS failures – Check the site performance from Counters (Iub, Service level, cell resources SHO, etc) and that site is carrying traffic – PrxNoise, receive link parameters, alarms – SC–reuse – UE performance ?Identified causes for Active Set Update failure – “Deaf” sites (PrxNoise) – Faulty HW – SC-reuse Presentation / Author / Date
HSDPA low• Low HSDPA throughput root causes analysis process throughput? START OSS counters measurement data collection Identify Low If throughput is low in network level, the throughput areas if NO reason can be also FTP/HTTP server exist settings (fire wall), Measurement tools etc. YES No Optimisation Required Low throughput NO YES due to low Ec/No or CQI Identify reason for low throughput if not RF If low throughput due to low Ec/No • Mobility (cell change too frequent) or Poor CQI, identify reason • No HSDPA coverage Business Object report • Bad Coverage Planning already delivered in order to • Iub / Iu User Plane Capacity • Quality issue due the neighbour measure all related HSDPA planning • Other HSDPA users in same WBTS/Cell throughput KPIs • DCH traffic too High (DPA, HSDPA Priority) • HSDPA Parameters are correctly set up Start Parameter Optimisation by tuning • Change Antenna tilt etc. • HSPDA Mobility parameters (FMCS) • PtxMaxHSDPA (WCEL) • Dynamic Flow Control set to ON (WBTS) Implement Changes DNO Optimization Processes / JC Ejarque
RU10 Reporting Suite Report Topic Name Report Name Report ID• RNC level system 1. System Program System Program RNC Level RSRAN084 1. System Program System Program Cell Level RSRAN000 program added 2. Capacity RNC Capacity RSRAN068 2. Capacity Node B Capacity RSRAN066• Corrections to 2. Capacity Cell Capacity RSRAN067 2. Capacity NRT Radio Bearer Statistics RSRAN013 Capacity report 3. Service Level Service/Session Accessibility Analysis RSRAN073 3. Service Level Service/Session Retainability Analysis RSRAN079• Modifications to 3. Service Level RAB Holding Times RSRAN021 3. Service Level Service Summary RSRAN003 Service level report 4. Traffic Allocated Traffic Amounts (R99 + HSPA) RSRAN070 (Streaming class 4. Traffic 4. Traffic Cell Data Volume and Throughput at RNC Traffic Summary RSRAN077 RSRAN026 added+ some other 4. Traffic 4. Traffic Used CE Capacity per RB Type in RNC Utilization Shares of Total Traffic Allocation Amounts RSRAN022 RSRAN071 corrections) 5. Mobility and Handover Active Set Size for NRT-RT Traffic RSRAN078 5. Mobility and Handover HSPA Serving Cell Change RSRAN033 5. Mobility and Handover IFHO Adjacencies RSRAN044 5. Mobility and Handover Inter-System Handover per Cause RSRAN019 RNC_169e:DR 5. Mobility and Handover Inter-System Handover Performance RSRAN023 + GAN HO 5. Mobility and Handover Inter-System Handover Reasons RSRAN018 5. Mobility and Handover ISHO Adjacencies RSRAN045 added, but load 5. Mobility and Handover Load Based HO Related Resources RSRAN047 5. Mobility and Handover Load Based IFHO/ISHO Performance RSRAN048 & service based 5. Mobility and Handover Load Based IFHO/ISHO Triggering RSRAN049 counters 5. Mobility and Handover Service Based IFHO/ISHO Performance RSRAN050 5. Mobility and Handover SHO Adjacencies RSRAN046 removed 5. Mobility and Handover Soft Handover Performance RSRAN028 Presentation / Author / Date
RU10 Reporting Suite• Modifications to Report Topic Name Report Name Report ID 8. Transport ATM Interface Traffic Load RSRAN081 KPIs due to 8. Transport ATM VCC Traffic Load RSRAN083 streaming class + 8. Transport 8. Transport ATM VPC Traffic Load FTM Packet Transport Performance RSRAN082 RSRAN076 64 HSDPA users/cell 8. Transport FTM Performance RSRAN072 8. Transport Iu-PS Throughputs RSRAN064 8. Transport Iub Throughputs RSRAN080 8. Transport Traffic on AAL5 RSRAN031 8. Transport Traffic on ATM Layer RSRAN029 8. Transport Traffic on Physical Medium Sub-Layer RSRAN030 8. Transport Transport Resource Reservations RSRAN069 7. HSPA Channel Switching and HSPA Layering RSRAN075 7. HSPA CQI Distribution RSRAN039 7. HSPA HSPA Code and Modulation Usage RSRAN034 7. HSPA HSPA Power Distribution RSRAN074 7. HSPA MAC-hs Efficiency RSRAN040 7. HSPA MAC-hs Retransmissions by Code and Modulation Usage RSRAN041 7. HSPA Number of HSPA Users and UE capability RSRAN051 6. Signalling NBAP Signalling RSRAN027 6. Signalling RRC Signalling RSRAN038 Presentation / Author / Date