3G Optimization & Trouble- shooting Process

3G RANOP 1Module 4 Drive Test Analysis# Nokia Siemens Networks Presentation / Author / DateFor internal useNote for teacherA set of example traces (Nemo) with comments can be used to demonstrate failures. Quickplace link: http://qp2.connecting.nokia.com/QuickPlace/npcommunityqp/PageLibraryC2256FB8004C9ABD.nsf/h_Index/2F7CFD979368E6F9C22572CA0030D936/?OpenDocument&ResortDescending=14# Nokia Siemens Networks Presentation / Author / DateFor internal use3G RAN Optimization

RF Optimisation and Neighbour PlanningRF optimisationNew Site IntegrationNeighbour plan optimisation

Signalling FlowsRRC EstablishmentRAB EstablishmentSHOISHO

Drive Test AnalysisDrive Survey AnalysisSystem Performance (RRC and RAB phases)

ClusterPreparationCluster health checksParameter consistency checkNeighbour list verificationUplink interference as a problem indicator

Inter-System Working and Optimisation3G2G Cell reselectionNeighbour PlanningHandover Process and compressed mode3G ISHO service analysis (AMR and PS)GSM ISHO Optimisation

Parameter OptimisationUse of Parameters to optimise network performance

HSDPA OptimisationHSDPA Air Interface CapacityHSDPA Drive Test KPIs and Parameter Optimisation# Nokia Siemens Networks Presentation / Author / DateFor internal useModule 4 Drive Test AnalysisObjectivesAfter this module the delegate shall be able to:-Understand the different elements required for an effective drive test programUnderstand how all aspects of drive data can be used to obtain a view of network performanceDifferentiate between genuine (RF) and non-genuine (system) failuresUnderstand the KPIs that can be obtained

# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test ProcessClusterPreparationDefine ClusterDefine Drive RouteData AnalysisLevels of ReportingFailure Type BreakdownPost Processing functionalityKPI Gap AnalysisData Preparation and CollectionServices to testKPI definitionsEquipmentExclusionsCall PatternsOSS AlarmsNetwork StatsTroubleShootingRoot Cause AnalysisCorrective ActionFurther data logging (maybe)New Site IntegrationRF TuningNetwork OptimisationNetwork Benchmarking (Golden Routes)Why Drive the network?# Nokia Siemens Networks Presentation / Author / DateFor internal useUsually Service verification is performed in the whole optimisation area (including several clusters) for performance acceptancePurpose is to reach target KPIs for defined services like AMR, CS video, Packet services (FTP server attached to the GGSN)Ideally this should only be done after RF optimisation but often call performance data is also collected during initial drive surveys to reduce costs (at the expense of complexity during analysis)Make gap analysis between measured KPIs and target KPIsInvestigate bad quality related to radio interfaceCoverage problems, Dominance, Interference, Missing neighboursPerform troubleshooting (call trace with logging, analysis etc.) in used to find out if the problem is related to System, configuration, blocking, UEs

Drive Test Analysis Test Equipment Nemo Outdoor Multi with UEs, Scanner and GPS

Land UnitNQMP

FTPServerImportant to drive with Call logging equipment and 3G and 2G scanner in the same vehicle

# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test Analysis Test Equipment, ScannerThe purpose of using the RF scanner is to be able to scan and measure all used carriers/cells and their corresponding DL scrambling codes.

For low coverage areasFor antenna installation problemsFor missing neighboursFor coverage optimisationWith the scanner you can get the following info from the surrounding cells:Different Scrambling codesCPCIH RSCP value (dBm)CPICH EcNo value (dB)# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test Analysis Test Equipment, UEThe Scanner measures all SCs, whereas the UE only measures SC signals from the cells that the system has informed/ordered the UE through the BCH (neighbour list) or via the measurement control message. RSCP Active/Monitored SetCarrier RSSIEc/No Active/Monitored SetUL/DL Data ThroughputThe BLER downlinkPilot BERRandom Access Initial Tx PowerRandom Access Preamble CountRandom Access Preamble StepRandom Access Tx PowerSIR target (UE dependent)UE Tx Power Call Statistic: AMR, CS and PS data calls# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test Analysis Call PatternsAMR CallMobile Originated Calls (MOC)2 min calls30 sec idleUE in Dual mode (2G/3G)Mobile Terminated Calls (MTC)2 min calls 30 sec idleUE in dual mode (2G/3G)Enough call samples have to be made to make the measurement statistically valid.In a 50 call sample one dropped call will cause a change in performance of -2%In a 500 call sample one dropped call will cause a change in performance of -0.2%Call length should be defined at the beginningWe can use different call testing patterns for different optimisation techniquesShort Calls (for Calls setup performance and delay)Long calls (for Drop call performance and SHO performance)PS CallGPRS Attach, PDP Context ActivationFTP Download (1MB file)/FTP Upload (500 KB file)PDP Context DeactivationGPRS DetachAlternate download and upload with 30 sec idle timeSession is upload or downloadUE in Dual mode (2G/3G)# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test Analysis Defining KPIs

Need to agreeWhat raw figures will containWhat End User will containOther cuts of Data# Nokia Siemens Networks Presentation / Author / DateFor internal useNeed to stress need for automation of the post processing. Include need to automate up to and including the breakdown of the failures

Drive Test Analysis Test Case definition ExamplesShort calls to test Call Setup Success Long calls to test Drop call ratio # Nokia Siemens Networks Presentation / Author / DateFor internal useNeed to Define the KPI measurement (from Drive test)Call Setup Success - CSSR (voice, circuit switched data)Successful call setup means that DL/UL Direct Transfer (CC: Alerting) message is received by UE.Call Setup Time (voice, circuit switched)Call setup delay is measured from L3 messages, starting from RRC Connection Setup message to DL Direct Transfer (CC: Alerting) message.Call Drop (voice, circuit switched)A dropped call occurs. The call will be dropped in case RRC connection release (not normal release) message has been send from RNC to UE.

Session Setup Success (packet switched)This is related to PDP context activation. Successfully activated PDP context means that activate PDP context accept message has been sent from RNC to UE (RRC: downlink direct transfer (SM:activate PDP context Accept)).Session Setup Time (packet switched)The session setup time is the delay between the time the UE sends the data session activation request until GPRS attach and PDP context activation has been successfully completed.Session Drop (packet switched)Session drop rate can be defined as the number of successful PDP deactivations against number of successful PDP activations.# Nokia Siemens Networks Presentation / Author / DateFor internal useDefinition of Call Set-Up Success Rate (CSSR)UERRC: Connection RequestRRC Connection Setup phaseResource Reservation in RNC, BTS, TransmissionRRC: RRC Connection Request SetupRRC Connection Access phase RNC waits reply from UE RRC: RRC Connection CompletedRRC: Initial Direct Transfer cm service requestRANAP: Initial UE MessageDIRECT TRANSFER (Call Proceeding)RANAP: RAB Assignment RequestRRC: Radio Bearer Set-upRRC: Radio Bearer Setup CompleteRAB Connection Setup phaseResource Reservation in RNC, BTS, TransmissionRANAP: RAB Assignment ResponseDIRECT TRANSFER (Alerting)BTSRNCCNDIRECT TRANSFER (Connect)DIRECT TRANSFER (Connect Acknowledge)RAB Connection Access phase RNC waits reply from UE Call Set-up Success RateCall Set-up TimeSuccessful call setup means that DL/UL Direct Transfer (CC: Alerting) message is received by UE# Nokia Siemens Networks Presentation / Author / DateFor internal useDefinition of the Call Completion Rate (CCR) UERNCMGWNode BCall EstablishedIu Release CommandIu Release CompleteRRC Connection ReleaseRRC Connection Release CompleteRRC Connection Release CompleteRRC Connection Release CompleteRadio Link Deletion RequestRadio Link Deletion ResponseALCAP: Release RequestALCAP: Release ResponseALCAP: Release RequestALCAP: Release ResponseCall ReleasedDirect Transfer (Disconnect)Direct Transfer (Release)Direct Transfer (Release Complete)DIRECT TRANSFER (Alerting)DIRECT TRANSFER (Connect)DIRECT TRANSFER (Connect Acknowledge)Call Drop RateCall Duration# Nokia Siemens Networks Presentation / Author / DateFor internal useDefinition of Session Setup Time - PSUECNRNCWBTSINITIAL DIRECT TRANSFER (Attach Request) Downlink Direct Transfer (Authentication & Ciphering Request) UE already has an RRC connectionSCCP: Connection Request SCCP: Connection Confirm RANAP: Authentication & Ciphering Request Security Mode Command Uplink Direct Transfer (Authentication & Ciphering Response) RANAP: Authentication & Ciphering Response RANAP: Security Mode CommandSecurity Mode Command RANAP: Security Mode CommandRANAP: Common IDDownlink Direct Transfer: Identity RequestRANAP: Identity RequestUplink Direct Transfer: Identity ResponseRANAP: Identity ResponseDownlink Direct Transfer: Attach AcceptDirect Transfer: Attach AcceptUplink Direct Transfer: Attach CompleteDirect Transfer: Attach CompleteINITIAL DIRECT TRANSFER (Active PDP Context Request) DIRECT TRANSFER (Active PDP Context Request) DIRECT TRANSFER (Active PDP context Accept) RANAP: RAB ASSIGNMENT REQUESTRRC: Radio Bearer Set-up RRC: Radio Bearer Set-up Complete RANAP: RAB ASSIGNMENT RESPONSERRC: Measurement Control INITIAL UE MESSAGE (GPRS Attach) Session Set-up Time# Nokia Siemens Networks Presentation / Author / DateFor internal useNon-genuine failuresMeasurement system fault (Collection Tool or Analysis)Genuine failuresRF issue (Coverage / Interference / Poor dominance)Missing neighbour System issue WBTS System issue RNC Core network issue System(Unknown )

WBTSRNCCore NWUE Iub IuIt is beneficial to categorise call failures during the analysis and reportingFailure Breakdown# Nokia Siemens Networks Presentation / Author / DateFor internal useSignalling diagram, check where the L3 signalling ends (last L3 message) to find out the failure locationSystem issue = NON-RAN issue, I.e. Iur-link (link dimensioning), non-Nokia element issue

The KPI measurement conditions should be used to define exclusion areas during drive test for acceptance of a cluster.All failures happening in those area, that do not respect the coverage requirements should be discarded.

Failure Breakdown# Nokia Siemens Networks Presentation / Author / DateFor internal useFailure Breakdown

AMR Call Setup Failures# Nokia Siemens Networks Presentation / Author / DateFor internal useSignalling diagram, check where the L3 signalling ends (last L3 message) to find out the failure locationSystem issue = NON-RAN issue, I.e. Iur-link (link dimensioning), non-Nokia element issue

Drive Survey Analysis Process Summary Diagram

# Nokia Siemens Networks Presentation / Author / DateFor internal useNon Genuine Call Setup Failure ScenariosMeasurement systems are often not perfect and may introduce errors in data collection or analysis

Examples of non-genuine failures seen:

Uplink: CM Service Abort within milliseconds from CM Service RequestCall attempt during Location Area update (LA clash)User initiated UL CC DisconnectLocation Area update interpreted as call setup failureCell reselection back to 3G from 2G interpreted as call setup failure

# Nokia Siemens Networks Presentation / Author / DateFor internal useNon Genuine Call Setup FailuresMeasurement system failures by drive test toolCM Service Abort within milliseconds from CM Service RequestNo time for response from NW

# Nokia Siemens Networks Presentation / Author / DateFor internal use

Non Genuine Call Setup FailuresMeasurement system failures by drive test tool Call attempt during Location Area update (LA update clash)LA Update RequestCall attemptRRC Release

# Nokia Siemens Networks Presentation / Author / DateFor internal useNon Genuine Call Setup FailuresMeasurement system failures by Actix workbookSuccessful or failed Location Area update interpreted as call setup failure

RRC Connection for Inter-RAT cell reselectionLA Update Request# Nokia Siemens Networks Presentation / Author / DateFor internal useUE can use the existing RRC Cx to send Service Request for CS domain even if it was setup for PS domain. For LU+Voice you should check whether the flag 'follow-on request pending' is 'yes' in the Location Update Request. In that case, the UE is allowed to send the Service Request on the same RRC Cx. If it is not set, the UE is not allowed : it should wait for RRC Cx Release, and then re-establish.

Non Genuine Drop Call ScenariosMeasurement system failure examples:Drive test toolUser initiated UL CC DisconnectAnalysis WorkbookInter-Rat cell reselection from 2G to 3G interpreted as drop callComplete (e.g 90 seconds) call on either 3G or 2GNo drop in the log file / same drop listed twice

# Nokia Siemens Networks Presentation / Author / DateFor internal useGenuine Call Setup Failure ScenariosRF issueInterference / Dominance / CoverageMissing neighbourSystem Issue - BTSNo response to RRC Connection RequestRRC Connection Reject to RRC Connection Request System issue - RNCCC Disconnect after Call Proceeding due to DL RRC Connection ReleaseCore NWCM Service Abort after CM Service RequestSystem issue (test number)CC Disconnect after CC Progress# Nokia Siemens Networks Presentation / Author / DateFor internal useGenuine Drop Call scenariosRF issueInterference / Dominance / CoverageMissing NeighboursSystem issue BTSSudden CC Disconnect due to DL RRC Connection ReleaseSudden drop to idle, no disconnect messagingSystem issue RNCSudden CC Disconnect due to DL RRC Connection Release

# Nokia Siemens Networks Presentation / Author / DateFor internal useFailure Location

Analyse the signalling flow to find the location of failure and potential causeUE log may only capture some of the messages# Nokia Siemens Networks Presentation / Author / DateFor internal use

Module 4 Drive Test AnalysisCall Setup Failure Analysis# Nokia Siemens Networks Presentation / Author / DateFor internal useDRNCUECNSRNCWBTS2. RRC connection set-up6. Service Established7. Branch addition/deletion & Active set update1. Cell search, BCCH decoding & RACH access3. UE CS-CN signalling4. RAB set-up8. Service Released5. UE CS-CN SignallingAMR CS Call Phases# Nokia Siemens Networks Presentation / Author / DateFor internal useStartBest servers RSCP > -102dBmBest servers Ec/No > -12dBCoverage OptimizationDominance OptimizationAICH(ACK) received?YesMissing Neighbour ?Neighbour list OptimizationNoNoNoYesUL coverage & RACH parameter. Optimization(changing serving cell)RRC ConnectionSetup received?(DCH) RRC Connection setupCompleted sent from UE?Radio Bearer setup failureReceived?Report & FinishCheck failure cause (Not radio problem/cell update)Report & Finish(Check failure cause)AC optimization (check PrxNoise& interferer around BTS)Report & FinishRRC Setup Reject received?YesNoYesYesYesReport & Finish (Reason of problem: L1 sync fail)Report & Finish(Check failure cause)Call Setup Failure Analysis ProcessABCDEYesYesNoNoNoNo# Nokia Siemens Networks Presentation / Author / DateFor internal useCall setup failures RF issueRF issue? Coverage / Interference / Dominance

ASee the example in Module 3 RF Optimisation# Nokia Siemens Networks Presentation / Author / DateFor internal useCall setup failures Missing NeighbourAMissing neighbour analysis over the whole route (3G-3G, 3G-2G)Search for failures due to missing 3G-3G neighbours Search for failures due to missing 3G 2G neighboursIt is suggested to place 2G scanner to the test vehicle

# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure Analysis- Block 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.UL Coverage limit: UL coverage of UE is smaller compared to serving cells DL coverage so that UEs Tx power cannot reach serving cell.

The Basic theory for RACH setup procedure and planning parameters can be found in Module 6 Parameter Optimisation

B# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure Analysis- Block B -UEWBTSRNCPreamble/RACHAcquisition Indicator/AICHRRC: RRC Connection Request/PRACHNBAP: RADIO LINK SETUP REQUESTRRC: RRC CONNECTION SETUP/FACHL1 SynchronisationNBAP: SYNCHRONISATION INDICATORRRC: RRC CONNECTION SETUP COMPLETE/DCHUE in CELL_DCH stateNBAP: RADIO LINK SETUP RESPONSEB# Nokia Siemens Networks Presentation / Author / DateFor internal useRACH Process DownlinkBSL1 ACK / AICHUplinkMSPreamble1Not detectedMessage partPreamble2PRACH_preamble_retrans# PRACH preambles transmitted during one PRACH cycle without receiving AICH responseUEtxPowerMaxPRACH RACH_tx_Max# preamble power ramping cycles that can be done before RACH transmission failure is reportedPowerRampStepPRACHpreamblePowerOffsetLastPreamblePRACHmessageInitial preample power:Ptx = CPICHtransmissionPower-RSCP(CPICH) +RSSI(BS) + PRACHRequiredReceivedCIB# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure Analysis- Block B-Solutions for RACH optimisationMax UE Tx power hit the UE_P_MAX(24dBm)?To increase PRACH_Preamble_retransOr PowerRampStepPRACHPreambleNoYesIs UL Interference abnormally HIGH?YesNoReport there might be an interfering source Nearby the serving cellChange the Serving cell to cover the problem Area=> UE is too far to reach the serving cellB# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure Analysis- Block B

BOpen loop Power Control parameters from RACH Info message# Nokia Siemens Networks Presentation / Author / DateFor internal useCall setup failures System issue BTSNo response to RRC Connection RequestGood RF conditionsWrong MHA settings or cable loss settings can cause the site not to hear the UEPrxNoise statistics, receive link parameters and HW units to be checked (faulty MHA, wrong MHA parameters, wrong cable / feeder loss parameters, faulty units)

C# Nokia Siemens Networks Presentation / Author / DateFor internal useCall setup failures System issue BTSRRC Connection Reject after RRC Connection RequestGood RF conditionsAdmission 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

C# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure AnalysisUE 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 can't admit more RABs to the cellC# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure AnalysisDuring 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.C# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Setup Failure AnalysisTo 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.D

# Nokia Siemens Networks Presentation / Author / DateFor internal use

CC Disconnect after Call ProceedingGood RF conditionsFailures 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.ECall setup failures System issue RNC# Nokia Siemens Networks Presentation / Author / DateFor internal useRNC fails to reserve recourses from NodeB

CC Disconnect after Call Proceeding (cont.)An example (site shows high values on counter RAB_STP_FAIL_CS_VOICE_BTS during the drive testIn the recent check the counter showed no failures.

ECall setup failures System issue RNC

# Nokia Siemens Networks Presentation / Author / DateFor internal use

Call setup failures Core NW

CM Service Abort after CM Service RequestGood RF conditionsSecurity Mode Command-message not received by UE, thus the failure is believed to be at Core Network.E# Nokia Siemens Networks Presentation / Author / DateFor internal useCall setup failures System Issue (test number)CC Disconnect after CC ProgressCause: 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 expiryE# Nokia Siemens Networks Presentation / Author / DateFor internal use

Module 4 Drive Test AnalysisDrop Call Analysis# Nokia Siemens Networks Presentation / Author / DateFor internal useStartBest servers RSCP > -102dBmBest servers Ec/No > -12dBCoverage OptimizationDominance OptimizationYesYesNeighbour list OptimizationMissing NeighbourYesCall Drop Failure Analysis ProcessSHO FailedInvestigate possible BTS or RNC problemNoISHO FailedNoISHO Failure AnalysisBYesSHO Failure AnalysisANoNoNo# Nokia Siemens Networks Presentation / Author / DateFor internal useCall Drop Failure Analysis Process (SHO Analysis)DL ASU receivedYesSC ClashUE Tx Power MaxFix SC ClashCPICH OptimisationUplink InterferenceLoad Optimisation/ External InterfererLink UnbalancedYesYesYesYesNoNoNoYesInter RNC HOCheck IurYes Congestion on target cell Load OptimisationNoYesNoCheck neighbour definition parametersCheck RF LevelsNoDL Tx Power Max YesStartDC# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop call failures RF issue

RF drops mostly due to poor dominance or interferencePoor coverage could lead to ISHO, although poor dominance or interference can cause ISHO to fail.Rapid field drop can cause drop due to coveragePoor dominance or interference can cause Compressed Mode (CM) to start even if RSCP is still good.In CM UE transmits with higher power (more interference) and spends less time on 3G (less accurate measurement reporting)Poor dominance or interference can lead to Active Set update failures and eventually to drop call.Poor dominance causes Active Set update failuresA# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop call failures RF issue

DL synchronisation is lost -> UE has stopped transmittingTrChAgg and DL DPCCH BER highA# Nokia Siemens Networks Presentation / Author / DateFor internal useLoss of downlink synchronisation forces the UE to stop transmitting which results in a subsequent loss of uplink synchronisation (T313, N313, N315)Radio link failures are caused primarily by a Node B losing uplink synchronisation across the air-interface (N_OUTSYNC_IND, T_RLFAILURE, N_INSYNC_IND)Drop call failures RF issue

Transport Channel BER. Btw UERNC (MAC layer) Sometimes DPCCH BER (btw UEWBTS) can be a better indicator of what's happening to the dedicated channel than the CPICH EcNo, in particular in the case that power control may not be tracking wellFairly good CPICH Pilot EcNoA# Nokia Siemens Networks Presentation / Author / DateFor internal useDedicated Physical Control Channel (control info) DPCCH pilot sequence is used for channel estimation as well as for the SIR ratio determination within the inner loop power controlDrop call failures System issue BTS

Drop to IDLEBSudden drop to idle, no disconnect messagingSite malfunctions to be checkedIn the example below site had faulty unit (WTR)# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop call failures System issue RNC

Sudden RRC Connection ReleaseDPCCH BERCC Disconnect due to DL RRC Connection Release No response to UL Measurement Reports In the example site had no alarms, good RF & BERNot able to add SC265 to Active Set, next call on the same cell => no failure.Difficult to troubleshoot if the failure does not happen systematically => follow up in the next weeks drive / do a separate drive test in the areaB# Nokia Siemens Networks Presentation / Author / DateFor internal useALWAYS SUSPECT NODE B FIRST, THEN RNCDrop call failures (SC conflict)Sudden drop to idle mode (no disconnect messaging)Cause of the failure: overshooting site and SC reuseShort term solution to add overshooting neighbour in ADJS definitions

Cell ABC, SC258

Transport channel BLER 100%C# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop Call - Uplink Interference

UL interference from the SIB7 message

D# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop Call Link BalanceUL & DL Power Control commands can help indicating problems in link balance.PC frequency is 1500 Hz, thus ideally the sum of PC commands to increase or decrease power is 1500E.g. if the sum of UL PC commands is < 1500, this would indicate UE is starting to loose synchronizationin Compressed Mode there is less PC commands, UE spends time on 2G

UE RX power control message: DL reception weak -> UE is ordering WBTS to increase power.

Sum of UL PC commands < 1500, UE not receiving all the PC commands.D# Nokia Siemens Networks Presentation / Author / DateFor internal useDrop call failures System issue RNC or BTS ?CC Disconnect due to DL RRC Connection Release is just a consequence of failure which can be due to different reasonsFrom UE point of view L3-messaging does not identify the point of failure distinctlyBTS or RNC failure? => Suspect BTS first, then RNC

Rule out BTS failuresCheck the site performance from Counters (Iub, Service level, cell resources SHO, etc) and that site is carrying trafficPrxNoise, receive link parameters, alarms SCreuseUE performance ?Identified causes for Active Set Update failureDeaf sites (PrxNoise)Faulty HWSC-reuse# Nokia Siemens Networks Presentation / Author / DateFor internal useALWAYS SUSPECT NODE B FIRST, THEN RNC

Module 4 Drive Test AnalysisDrive Test Analysis Reporting# Nokia Siemens Networks Presentation / Author / DateFor internal useDrive Test Analysis Reporting Levels OptimiserVery High Level KPIs that give a users perception of the network (Network KPI)KPIs that provide an Engineering view of network performance e.g CSSR, CDR, OCSR, SHO performance. (KPIs required for each optimisers area)Highly detailed KPIs that give a detailed picture of network performance at an Engineering level and allow root cause analysisRegional Optimisation ManagerSenior ManagementProcessing Drive Data to provide the information required at the bottom level means that the higher level information can be easily extractedThe different reporting levels may want to see KPIs based on different cuts of the data (e.g. raw or end user)# Nokia Siemens Networks Presentation / Author / DateFor internal useNon-genuine failures to be removed from the raw KPIsAttempt and failure (i.e. the whole call) should be removed from the raw KPIs some scenarios:CM Service Abort within milliseconds from CM Service Request Call attempt during Location Area update (LA clash) User initiated UL CC DisconnectCell reselection back to 3G from 2G Location Area update interpreted as call setup failureOnly the failure should be removed from the raw KPIs for some scenariosComplete 90 seconds call on either 3G or 2GNo drop in the log file

KPI reportingNon-genuine failures to be removed from the raw KPIs

Non-genuine call setup failures removedNon-genuine drops removedFinal KPIsFinal KPIs# Nokia Siemens Networks Presentation / Author / DateFor internal useKPI reportingWeekly KPI trends (non-genuine failures should be excluded)

# Nokia Siemens Networks Presentation / Author / DateFor internal useTime on 3G KPI reportingBTS failure chart (call setup failure & drops)Cumulative number of failures that occurred per site over timeIf the UE is spending only a small percentage of time on 3G problems may not be identified.

CELL_CCell_ACell_DCELL_B# Nokia Siemens Networks Presentation / Author / DateFor internal useBTS failure examples: CELL_ALong history of failures (over weeks 46, 47, 02)Call Setup failure scenarios: CC Disconnect after CC Call ProceedingCM Service Abort after CM service Request3rd sector showing low average PrxNoise 108 dBm Commissioning data (feeder loss) was found incorrect.After this site was still failing, not carrying traffic. Alarm 7750 failure in WCDMA BTS O&M ConnectionCOCO rebuilt (27.1.05)

# Nokia Siemens Networks Presentation / Author / DateFor internal useBTS failure examples: CELL_BFailures only on week 49No response to RRC Connection RequestNo alarmsAt WBTS: MHA parameters okAt RNC: MHA=0, cable loss = 3 dB (DPCCH init pwr)PrxNoise checked OK, OMC statistics showed the site carried traffic during the drive.No failures in the following weeks drives# Nokia Siemens Networks Presentation / Author / DateFor internal useBTS failure examples: CELL_CFailures over weeks 44, 45, 49, 50No response to RRC Connection Request most frequent failure, also one case of sudden drop to idle.Test calls were made, the counters were not incremented during the test. Protocol analyser proved no activity in Iub. The counters were incremented only after site reset.Alarm WSMA RR-bus errorThe site had faulty WTR, incorrect feeder loss in the commissioning file.

# Nokia Siemens Networks Presentation / Author / DateFor internal useTest calls were made, the counters were not incremented during the test. Protocol analyser proved no activity in Iub. The counters were incremented only after site reset.

BTS failure examples: CELL_DFailures on weeks 47 and 48No response to RRC Connection RequestIncorrect feeder loss in commissioning data.# Nokia Siemens Networks Presentation / Author / DateFor internal useModule 4 Drive Test AnalysisSummary

Services to be measured and KPIs to be calculated need to be clearly definedVarious call patterns exist to exercise the KPIsReporting Levels should be understoodDefine and agree exceptions in advance

# Nokia Siemens Networks Presentation / Author / DateFor internal useVersion controlVersionDateStatusOwnerRAN042006Base versionMike Roche, Steve Hunt, Gareth Davies, Pekka RantaRAS051_v1.024. 04. 2007Example case availableMinor changes checked for RAS051 levelKirsi Tervinen# Nokia Siemens Networks Presentation / Author / DateFor internal use

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RRC: Initial Direct Transfer message is sent using acknowledged mode RLC to the CS core domain. Routing is to be based upon the local P-TMSIThe NAS message is not read by the RNC but is forwarded to the multimedia gateway. The NAS message includes the IMSI as a UE identity The SCCP: Connection Request message establishes the connection orientated signalling link in the same way as it was for the RRC connection phase.This does not reserve any resources for the AMR call itself.The Connection Confirm message identifies the RNC with a destination local reference which is the same as the source reference within the Connection Request messageThe Connection Confirm message identifies the CS core with a source local referenceThe CS core sends a RANAP: Location Reporting Control message to the RNC requesting information regarding the location of a particular UEThe RANAP: Common ID message specifies the IMSI belonging to the UEThe Security Mode Command message triggers the start or stop of ciphering and integrity protection.