释放流程及异常原因分析课件

释放流程及异常释放原因分析2016-05张恒释放流程及异常释放原因分析2016-05<Changeinformationclassificationinfooter>概述主要内容说明本次主要讨论的内容：LTE业务释放类型及相应信令流程的详解；相关的counter触发定义，以及异常问题分析；通过对这些内容的梳理和讨论，能够了解LTE释放的理论知识，并且在日常KPI和Log分析方面，提供帮助。<Changeinformationclassifica释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionrelease异常释放的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<Changeinfor<Changeinformationclassificationinfooter>业务承载类型LTE业务承载类型LTE的业务承载类型分为默认承载、专用承载两种：默认承载：UE开机时获得承载，一定是MME发起的业务，优先级特别低，NonGBR；专用承载：一定是由PGW触发建立的；一个UE可以有不同的专用承载；GTPvariant:EPSbearerterminationinPGWSRB与默认、专用承载关系<Changeinformationclassifica<Changeinformationclassificationinfooter>业务承载类型无线承载分类SRB–SignallingRadioBearers（SRBs）的定义是，仅用于传输RRC和NAS消息的RB（RadioBearer）；DRB–DataRadioBearer，用于传输业务数据的无线承载；与S1-U承载共同组成E-RAB.分为UM、AM两种；<Changeinformationclassifica<Changeinformationclassificationinfooter>业务承载类型UEcontext及E-RABE-RAB–UE至SGW之间的承载，E-RAB是指用户平面的承载，由S1-U承载和DRB（DataRadioBearer，数据无线承载）串联而成，进入LTE系统的业务数据主要通过E-RAB进行传输。因此对于LTE，业务管理主要是在E-RAB层次上进行的。–一个UE可以有多个E-RAB，目前最多支持8个EPS承载（５个AM

DRB，3个UM

DRB）.–在应用上，E-RAB常出现于性能指标的统计中，例如：E-RAB建立成功率。E-RAB建立成功指eNodeB成功为UE分配了通信通道的无线资源和用户面的无线承载，所以这个指标反映了eNodeB或小区接纳业务的能力，可以用来考虑系统负荷情况。<Changeinformationclassifica<Changeinformationclassificationinfooter>业务承载类型UEcontext及E-RABUEcontext–IncludingE-RABcontext,securitycontext,roamingrestriction,UES1signallingconnectionID(s),heeNB.在源eNB的UE上下文中还包含了与漫游和接入限制有关的信息；–InitialUEcontext只能由MME发起，一个UE只有一个UEcontext；–一个eNBUEcontext是eNB内和一个处于激活状态的UE相关联的一个信息块。这块信息是为了维持E-UTRAN提供给这个激活态UE的服务所必须的信息；–eNBUEcontext是在UE迁移到激活状态之后开始建立的；或者，eNBUEcontext是在切换目标eNB完成切换资源分配（切换准备阶段）之后开始建立的。RRCconnection

层三信令连接，UE保持非IDLE的必须连接，一个UE只有一个RRCconnection，一旦连接释放，UE所有业务释放，并进入RRC_IDLE态；<Changeinformationclassifica<Changeinformationclassificationinfooter>LTE完整业务流程默认承载建立信令流程（Attach）Steps:RandomAccessInitialNASmsgNASsecurityS1initsetupRRCsec+UEcapSRB2/DRBsetupNASreply<Changeinformationclassifica<Changeinformationclassificationinfooter>LTE完整业务流程RA及RRC连接建立流程SRB0：RRCconnectionrequest、RRCconnectionsetup（消息中包含SRB1建立的相关信息）；SRB1：RRCconnectionsetupcomplete；<Changeinformationclassifica<Changeinformationclassificationinfooter>LTE完整业务流程专用承载建立流程DedicatedBearerEstablishment：E-RAB建立<Changeinformationclassifica释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionreleaseAbnormalrelease的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<Changeinfor<Changeinformationclassificationinfooter>业务释放类型release根据业务承载类型，业务释放过程也分为三类：E-RABreleaseThepurposeoftheE-RABReleaseprocedureistoenablethereleaseofalreadyestablishedE-RABsforagivenUE；E-RAB释放后，UE仍然可以处于ECM-CONNECTED状态；UEcontextreleaseIftheeNBwantstoremoveallremainingE-RABs,e.g.,foruserinactivity,theUEContextReleaseRequestprocedureshallbeusedinstead.当UE回到ECM-IDLE状态时，MME向eNodeB发UECONTEXTRELEASE消息。收到这条消息后，eNodeB删除eNBUE

context。MME继续保留MMEUEcontext.<Changeinformationclassifica<Changeinformationclassificationinfooter>业务释放类型release根据业务承载类型，业务释放过程也分为两类：RRCconnectionreleaseThepurposeofthisprocedureistoreleasetheRRCconnection,whichincludesthereleaseoftheestablishedradiobearersaswellasallradioresources；RRC连接释放后，UE进入RRC_IDLE状态。<Changeinformationclassifica<Changeinformationclassificationinfooter>E-RABrelease释放类型：E-RABrelease根据3GPP定义(3GPPTS36.413)，E-RABrelease过程分为两大类：ENodeBInitiatedMMEInitiatedE-RAB管理的相关信息都embed在context管理信令中。MMEInitiatedENodeBInitiated<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解E-RABrelease：MMEInitiatedE-RABreleasecommand消息内容：shallcontaintheinformationrequiredbytheeNBtoreleaseatleastoneE-RABintheE-RABToBeReleasedListIE.IfaNAS-PDUIEiscontainedinthemessage,theeNBshallpassittotheUE.E-RABToBeReleasedListIE.theUEAggregateMaximumBitRateIE.E-RABreleaseresponse消息内容：-AlistofE-RABswhicharereleasedsuccessfullyshallbeincludedintheE-RABReleaseListIE.-AlistofE-RABswhichfailedtobereleased,ifany,shallbeincludedintheE-RABFailedtoReleaseListIE.<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解E-RABrelease：MMEInitiatedeNB收到E-RABRELEASECOMMAND后，eNB将会释放被请求的ERABs.对于每一个要释放的E-RAB，eNB会释放其相应的DRB和空口资源。TheeNBshallpassthevaluecontainedintheE-RABIDIEreceivedfortheE-RABtotheradiointerfaceprotocolforeachDataRadioBearertobereleased.TheeNBshallreleaseallocatedresourcesonS1fortheE-RABsrequestedtobereleased.Networktriggered(fromDeleteBearer)<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解E-RABrelease：eNBInitiatedE-RABRELEASEINDICATION消息内容：TheE-RABRELEASEINDICATIONmessageshallcontainatleastoneE-RABreleasedattheeNB,intheE-RABReleasedListIE.UponreceptionoftheE-RABRELEASEINDICATIONmessagetheMMEshallnormallyinitiatetheappropriatereleaseprocedureonthecorenetworksidefortheE-RABsidentifiedintheE-RABRELEASEINDICATIONmessage.InteractionwithUEContextReleaseRequestprocedure:IftheeNBwantstoremoveallremainingE-RABs,e.g.,foruserinactivity,theUEContextReleaseRequestprocedureshallbeusedinstead.<Changeinformationclassifica释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionreleaseAbnormalrelease的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<Changeinfor<Changeinformationclassificationinfooter>UEcontextrelease释放类型：UEcontextrelease根据3GPP定义(3GPPTS36.413)，UEcontext过程同样分为两大类：ENodeBInitiatedMMEInitiatedThisprocedureisusedtoreleasethelogicalS1-APsignallingconnection(overS1-MME)andallS1bearers(inS1-U)foraUE.TheprocedurewillmovetheUEfromECM-CONNECTEDtoECM-IDLEinboththeUEandMME,andallUErelatedcontextinformationisdeletedintheeNodeB.<Changeinformationclassifica<Changeinformationclassificationinfooter>UEcontextrelease释放的触发条件—UEContextReleaseRequest

该信令，使基站可以根据E-UTRAN的需要，向MME请求UE-associatedS1链接的释放；ENodeB发起的Contextrelease情况：Normalrelease：“UserInactivity”，‘CSFallbacktriggered’，‘UENotAvailableforPSService’，‘Inter-RATRedirection’，‘TimeCriticalHandover’，‘HandoverCancelled’，“Detach”Abnormalrelease：“RadioConnectionWithUELost”,“CSGSubscriptionExpiry”,“Redirectiontowards1xRTT”，UnspecifiedFailure，O&MIntervention，RepeatedRRCsignallingIntegrityCheckFailure，etc.ENodeBInitiated<Changeinformationclassifica<Changeinformationclassificationinfooter>UEcontextrelease释放的触发条件—UEContextReleaseCommandMMEInitiated

该信令，使MME在多种情形下，可以控制UE-associated链接的释放；MME发起的Contextrelease情况：Normalrelease：e.g,completionofatransactionbetweentheUEandtheEPC,orcompletionofsuccessfulhandover,orcompletionofhandovercancellation,orreleaseoftheoldUE-associatedlogicalS1-connectionwhentwoUE-associatedlogicalS1-connectionstowardthesameUEisdetectedaftertheUEhasinitiatedtheestablishmentofanewUE-associatedlogicalS1-connection,ortheUEisnolongerallowedtoaccesstheCSGcell(i.e.,theUEbecomesanon-memberofthecurrentlyusedCSGcell).Abnormalrelease：“LoadBalancingTAURequired”，‘authenticationfailure’,‘detach’,‘notallowedCSG’

celetc.<Changeinformationclassifica<Changeinformationclassificationinfooter>UEcontextrelease正常释放原因信令实例eNBinitiatedMMEinitiatedMMEinitiatedeNBinitiatedeNBinitiated<ChangeinformationclassificaUEcontextrelease异常释放原因信令实例MMEinitiatedeNBinitiatedMMEinitiatedMMEinitiatedMMEinitiatedUEcontextrelease异常释放原因信令实例MM<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：ENodeBInitiatedTheUECONTEXTRELEASEREQUESTmessageshallindicatetheappropriatecausevalue,e.g.,“UserInactivity”,“RadioConnectionWithUELost”,“CSGSubscriptionExpiry”,“CSFallbacktriggered”,“Redirectiontowards1xRTT”,“Inter-RATRedirection”,“UENotAvailableforPSService”,fortherequestedUE-associatedlogicalS1-connectionrelease.InteractionswithUEContextReleaseprocedure:TheUEContextReleaseprocedureshouldbeinitiateduponreceptionofaUECONTEXTRELEASEREQUESTmessage.<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：ENodeBInitiatedTransitionduetoinavtivity.UEconsumeslessbatterypowerinidlemode;LessactiveUeswhichnetworkhastohandle;Fastgoingtoinactivityhasdrawbackoflongerconnectionsetuptime(moretransitionsidletoconnected).<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：ENodeBInitiated<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：MMEInitiatedTheUECONTEXTRELEASECOMMANDmessageshallcontaintheUES1APIDpairIEifavailable,otherwisethemessageshallcontaintheMMEUES1APIDIE.TheMMEprovidesthecauseIEsetto“LoadBalancingTAURequired”intheUECONTEXTRELEASECOMMANDmessagesenttotheeNBforallloadbalancingandoffloadcasesintheMME.MMEUES1APisreleasedwhentheS1connectionisreleased(nexttimeanewvalueisassigned)eNBUES1APisreleased<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：MMEInitiatedUponreceptionoftheUECONTEXTRELEASECOMMANDmessage,theeNBshallreleaseallrelatedsignallinganduserdatatransportresourcesandreplywiththeUECONTEXTRELEASECOMPLETEmessage.IncaseofeNBsupportingL-GWfunctionforLIPAoperation,theeNBshallalsoreleasethenodeinternaltunnelresources.<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：MMEInitiated<Changeinformationclassifica<Changeinformationclassificationinfooter>释放流程信令详解UEcontextrelease：MMEInitiated<Changeinformationclassifica释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionreleaseAbnormalrelease的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<Changeinfor<Changeinformationclassificationinfooter>RRCconnectionrelease释放类型根据3GPP定义(3GPPTS36.331)，E-UTRANinitiatestheRRCconnectionreleaseproceduretoaUEinRRC_CONNECTED：RRCconnectionreleaseThepurposeofthisprocedureistoreleasetheRRCconnection,whichincludesthereleaseoftheestablishedradiobearersaswellasallradioresources.RRCconnectionreleaserequestedbyupperlayersThepurposeofthisprocedureistoreleasetheRRCconnection.AccesstothecurrentPCellmaybebarredasaresultofthisprocedure.<Changeinformationclassifica<Changeinformationclassificationinfooter>RRCconnectionrelease释放原因ThereleaseoftheRRCconnectionisinitiatedbyE-UTRAN.Theproceduremaybeusedtore-directtheUEtoanotherfrequencyorRAT.InexceptionalcasestheUEmayaborttheRRCconnection,i.e.movetoRRC_IDLEwithoutnotifyingE-UTRAN.<Changeinformationclassifica释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionreleaseAbnormalrelease的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<ChangeinforCalldropWhoInitiatesDrops,UE,MMEoreNB?<Changeinformationclassificationinfooter>UEcan”initiateadrop”bystartingRRCConnectionRe-establishmentNote:besidesRLFalsoothercausescantriggerRRCConnRe-EstablishmenteNBcaninitiateabnormalS1+RRCreleaseduetoRadionetworklayerproblem(TAtimer,RLF,PDCCHOrderfailure)Transportnetworklayerproblem(GTP-Uerror,Trelocexpiry,PathSwitchproblem)Otherabnormalcause

MMEcaninitiateabnormalS1+RRCreleaseduetoRadionetworklayerproblemOtherabnormalcauseCalldropWhoInitiatesDrops,UEinitiateddropRLF<Changeinformationclassificationinfooter>WhenUEisinRRC_CONNECTEDandRRCsecurityisactive,itcantriggerRRCConnectionRe-establishmentuponT310expiryuponreachingthemaximumnumberofULRLCretransmissionsuponhandoverfailure(T304expiry)uponnon-HOrelatedrandomaccessproblemIfsuccessful,RRCConnRe-EstablishmentreconfiguresSRB1toresumedatatransferofRRCmsgsre-activatesRRCsecuritywithoutchangingalgorithmsNOTE:DRBshouldbere-configuredafterSRB1NOTE:ifUEisinRRC_CONNECTEDwhileRRCsecurityisnotactive,UEgoestoRRC_IDLE,performscellreselectionandTAUUEinitiateddropRLF<ChangeinUEinitiateddropRLFduetoT310ExpiryatUE<Changeinformationclassificationinfooter>UEinitiateddropRLFduetoT3UE

initiateddropRLFduetoMaximumULRLCRe-TxReached<Changeinformationclassificationinfooter>fromRRCConnectionReconfiguration:drb-ToAddModListdrb-ToAddModListvalue1drb-Identity :1rlc-Configamul-AM-RLCt-PollRetransmit :ms40pollPDU :p32pollByte :kB25

maxRetxThreshold :t8UEinitiateddropRLFduetoMaUE

initiateddropRLFduetoHOFailure<Changeinformationclassificationinfooter>fromRRCConnectionReconfiguration:mobilityControlInfotargetPhysCellId :33

t304 :ms1000newUE-IdentityBin :14EB(=5355)UEinitiateddropRLFduetoHOUE

initiateddropRLFDuetoNon-HORandomAccessFailure<Changeinformationclassificationinfooter>“Non-HOrandomaccess”meansPDCCHorder-triggeredRARandomAccessSchedulingRequestUEinitiateddropRLFDuetoNo释放流程及异常释放原因分析主要内容<Changeinformationclassificationinfooter>业务承载类型及业务建立过程业务释放类型及相应流程、原因E-RABreleaseUEcontextreleaseRRCconnectionreleaseAbnormalrelease的触发情景详解UEinitiateddropeNBinitiateddrop异常释放relatedCounterTriggersNetwork/FieldKPI及Drops分析Summary释放流程及异常释放原因分析主要内容<ChangeinforeNBinitiateddropRLF<Changeinformationclassificationinfooter>

eNBcandropthecallduetofollowingtriggers

eNB-detectedradiolinkproblemsPUSCHRLFCQIRLFAck/NackRLFPDCCHOrderfailureSRSRLFTAtimerexpiryMaximumRLCretransmissionsexceededGTP-UfailureeNBinitiateddropRLF<ChangeieNBinitiateddropRadioLinkProblemDetectionateNB<Changeinformationclassificationinfooter>eNBradiolinkproblemdetectionmechanismsareNSN-internallyspecifiedMultiplemethods(called“linkmonitors”)aredefinedtodetectaradiolinkproblemintheeNB.Whenonelinkmonitordetectsaproblem,itisreallyaradiolinkproblemevenifotherlinkmonitorshavenotyetindicatedanything.Eachlinkmonitorhasitsinternalcriteriatodecidewhenradiolinkproblemisflaggedandde-flagged(radiolinkrecovers).IftheRLPpersistslongerthanT_RLF,RRC+S1releaseistriggeredT_RLF=t310+t311(eNB-internaltimer)Linkmonitors:UplinkPUSCHDTXdetectionforscheduleduplinkdataCQIDTXdetectionforperiodicCQIreportsinPUCCHandPUSCHUplinkAck/NackDTXdetectionfortransmitteddownlinkdataPDCCHOrderRLFSRSDTXdetection(TD-LTE)eNBinitiateddropRadioLinkPeNBinitiateddrop1.PUSCHRLF:RlsCause_PuschRlf_ON<Changeinformationclassificationinfooter>WhenUEisscheduledforPUSCHtransmission,eNBexpectstoreceiveULtransmissiononthescheduledPRBsIfsignalfromUEcannotbedetectedatall,PUSCHDTXisdeclaredNOTE:ThecasewhereULTBSisreceivedbutitfailsCRCcheckisnotDTX(it’saNACK)DTXPUSCHindicationisprovidedbytheULphysicallayer.TheresultisreceivedbyLTEMACinreliableULtransmissionFlagparameter.Bothcounter-basedandtimer-basedRLFdetectionissupportedTimer-basedPUSCHRLFdetection:If“DTX“isreceivedonthePUSCHforaconfigurableperiodoftime(rlpDetMaxTimeUl),PUSCHRLFissetonCounter-basedPUSCHRLFdetection:If“DTX“isreceivedonthePUSCHforaconsecutivenumberoftimes(rlpDetMaxNoUl),

PUSCHRLFissetonTherecoveryoftheradiolinkisindicatedwhenforaconfigurablenumberofcontiguousULresourceassignmentsdataisdetectedonPUSCH(ACKorNACKreceived).DefinedbyparameterrlpDetEndNoUl.eNBinitiateddrop1.PUSCHRLFeNBinitiateddrop1.PUSCHRLF:RlsCause_PuschRlf,Counter-basedRLFDetectionExample<Changeinformationclassificationinfooter>T_RLF=T310+T311<pname="rlpDetMaxNUl">3</p>

<pname="rlpDetEndNUl">2</p>

vendor-fileparametersinthisexample:eNBinitiateddrop1.PUSCHRLFeNBinitiateddrop2.PeriodicCQIRLF:RlsCause_CqiRlf_ON

<Changeinformationclassificationinfooter>TheeNBsupportsCQIDTXdetectionforperiodicCQIreportsonPUCCHandPUSCH.IfMAClayerreceivesnCqiDtxconsecutivereportsfromULPHY,theMACdeclaresCqiRLF_ON

IftheMAChassetCqiRLF_ONforaspecificUEandnCqiRecconsecutiveCQIreportsareagaindetectedsuccessfullyforthatUE,theMACsetsCqiRLF_OFFTheparametersnCqiDtxandnCqiRecareinthevendor-specificparameterfileForbothPUSCHandPUCCHtheperiodicCQIisencodedusingaReedMullerblockcodeandcomesalongwithoutanyCRC.Hence,theULPHYindicatesaDTXdetectionforperiodicCQIreportsonPUCCHorPUSCHwheneverareportisconfiguredbutnoreliabletransmissionfromtheUEcouldbedetected.SotheoutputofthedetectorshallbeeitherthedetectedCQIreportoraDTXindication.NOTE:CQI_RLFdetectiondoesnotapplytoaperiodicCQIreportonPUSCHeNBinitiateddrop2.PeriodiceNBinitiateddrop2.PeriodicCQIRLF:RlsCause_CqiRlf,Example

<Changeinformationclassificationinfooter>

<pname="nCqiDtx">6</p>

<pname="nCqiRec">1</p>vendor-fileparametersinthisexample:T_RLF=T310+T311eNBinitiateddrop2.PeriodiceNBinitiateddrop3.Ack/NackRLF:RlsCause_AckNackRlf_ON<Changeinformationclassificationinfooter>AfterDLscheduleddata,eNBexpectsHARQACKorNACKonPUCCHorPUSCHatknownULTTITimer-basedACK/NACKRLFdetection:IfACK/NACK“DTX“isreceivedforaconfigurableperiodoftime(rlpDetMaxTimeDl),ACK/NACKRLFissetonCounter-basedACK/NACKRLFdetection:IfACK/NACK“DTX“isreceivedforaconsecutivenumberoftimes(rlpDetMaxNoDl),

ACK/NACKRLFissetonTherecoveryoftheRLFisindicatedwhenforaconfigurablenumberofcontiguousACK/NACKopportunitiesACKorNACKisdetectedonPUSCHorPUCCH(noDTX).DefinedbyparameterrlpDetEndNoDl..eNBinitiateddrop3.Ack/NackeNBinitiateddrop4.PDCCHOrderRLF<Changeinformationclassificationinfooter>IfthereDLdataineNBbufferandUEisout-of-sync,UEmustbebroughtbacktoin-sync(timealigned)withaRAprocedurebeforeDLdatacanbesentSignalingofdedicatedRApreambleviaPDCCH(so-calledPDCCHorder)isdoneusingDCIformat1AIncasethatPDCCHorderfailsforaUE(i.e.,notransmissionofassigneddedicatedpreambledetectedbyeNodeB,ornomsg3transmission)thePDCCHordershallberepeatednoRepPdcchOrdertimes(R&Dconfigurableparameter,range0-3,default1),againusingtheselectedpreambleandconsideringDRXstatusoftheUEaccordingly.FinalfailureofthePDCCHorderprocessshallbeindicatedasradiolinkproblemtohigherlayerswithcause“PDCCHorderfailure”IfinactivitytimerfortheUEhasexpiredthenthereisnoT_RLFtimerinvolvedS1andRRCreleasedimmediatelyeNBinitiateddrop4.PDCCHOrdeNBinitiateddrop5.SRSRLF<Changeinformationclassificationinfooter>TheeNBsupportsSRSDTXdetectionforradiolinkproblemdetectionIfMAClayerreceivesnSrsDtxconsecutivereportsfromULPHY,theMACdeclaresSRSRLFIftheMAChassetSRSRLFforaspecificUEandnSrsRecconsecutiveSRStransmissionsaresuccesfullydetectedtheUE,theMACsetsSRSRLFOFFHencetheSRSRLFhassimilarmechanismasCQIDTXRLFTheparametersnSrsDtxandnSrsRecareoperator-configurableP7defaultvaluesfromRL15SCF:

<pname="nSrsDtx">8</p> <pname="nSrsRec">1</p>eNBinitiateddrop5.SRSRLF<CeNBinitiateddropWhenisDrop(=RRC+S1release)TriggeredbyeNB?<Changeinformationclassificationinfooter>3GPPdoesnotspecifyeNBradiolinkfailures,butNSNeNBmimicsthebehaviouroftheUERLFspecifiedin3GPP.Whenaradiolinkproblemisdetected,aneNB-internaltimer(T_RLF)isstarted.ThetimerT_RLFisstoppedwhenincaseofradiolinkfailurerecovery.ForagivenUE,T_RLFisstartedwhenanyofthePUSCHRLF,CQIRLF,SRSRLForAckNackRLFissettoONstateForagivenUE,T_RLFisstoppedonlyifallRLFsareOFFWhenthetimerT_RLFexpires,theUEisreleasedfromtheeNBusingeNBinitiatedS1release+RRCconnectionrelease–>calldropT_RLF=T310+T311eNBinitiateddropWhenisDropeNBinitiateddropRLFTriggeringbyeNB,Signalling<Changeinformationclassificationinfooter>OnlyL2AckneededforsuccessfulRRCConnRelease.IfL2AcknotreceivedaftertimertL2AckRrcRelexpires(def=800ms),RRCisreleasedanyway.NOTE:NoRLCAckneededforRRCConnectionRelease.NoreTxforRRCConnectionReleaseeNBinitiateddropRLFTriggerieNBinitiateddropIn-SyncandOut-Of-SyncStates:Overview<Changeinformationclassificationinfooter>RRCconnectedsubstates:ULin-syncandULout-of-syncUplinkRASRordownlinkPDCCHordertobringUEbackin-synceNBinitiateddropIn-SyncandeNBinitiateddropTATimerExpiryatUE<Changeinformationclassificationinfooter>AsUEdetectsOut-of-SyncstatususingaTimingAlignmentTimer,thetimershallbestartedorrestartedwheneveraninitialTAoraTAupdatecommandisreceived(see[3GPP-36.321],section5.2).Ifthetimerexpires,theUEdetectsout-of-syncstatus.3GPPTS36.321:WhentimeAlignmentTimer

expiresatUE,UEMAClayershall:flushallHARQbuffers;notifyRRClayertoreleasePUCCH/SRS;clearanyconfigureddownlinkassignmentsanduplinkgrants3GPPTS36.331:UponreceivingaPUCCH/SRSreleaserequestfromMAClayer,theUERRCshall:releaseperiodicCQIreportingconfig,ieitstopsCQIreportingonPUCCHreleaseSchedulingRequestConfigeNBinitiateddropTATimerExpeNBinitiateddropIn-Sync,Out-Of-SyncHandlinginRL30<Changeinformationclassificationinfooter>ParameterLNCEL/applyOutOfSyncStatedefineshoweNBhandlesTAexpiryextendedDrxOnly:onlyUEsbeingconfiguredwithextendedsettingsforthelongDRXcyclearenotdroppedifTAtimerexpires(default)allDrx:allUEsbeingconfiguredforDRXprovidedthatappliedDRXprofileallowsarenotdroppedifTAtimerexpiresallUEs:allUEsindependentlyofDRXconfigurationprovidedthatbearercombinationallowsarekeptRRCConnectedevenifTAtimerexpires.IfDRXisnotusedatall,thensetting‘allUEs’shouldbeusedtopreventeNBdropsduetoTAtimerexpiryeNBinitiateddropIn-Sync,OuteNBinitiateddropIn-SyncNormalCase<Changeinformationclassificationinfooter>ProceduredescribeshowanUEgetsbackintoULsynchronizationfromastateinwhichthetimealignmenthasbeenlosteNBdetectsthatthetimealignmentoftheUEisULout-of-sync(e.g.expirationoftimealignmenttimer)UEalsodetectsout-of-sync(sametrigger)andreleasesresourcesonPUCCHforCQIreportingandschedulingrequestIfeNBdetectsDLdata(eitherdatatrafficorRRCsignalling)eNBsendsaPDCCHorderforRAproceduretoUE(DCI1Awithspecificcodepoint;preferablynon-contentionbasedRAdependingonpreambleavailability)UEstartsarandomaccessprocedureeNBrecognizeswhenrandomaccessoftheUEwassuccessfulandUEULtimealignmentisback“in-sync”IfUEdetectsULdata(eitherdatatrafficorRRCsignalling):UEstartsarandomaccessprocedure(contention-based)eNBrecognizeswhenrandomaccessoftheUEwassuccessfulandUEULtimealignmentisback“in-sync”eNBtriggerstheRRCprocedureRRCConnectionReconfigurationtoconfigure(again)thePUCCHresourcesforCQIreportingandschedulingrequestSameresourceusedforsimplificationbutcouldbeoptimizedoptionallyNote:theRRCmessageRRCConnectionReconfigurationCompleteisalreadysentusingtheconfiguredPUCCHresourcesforschedulingrequest.eNBinitiateddropIn-SyncNormeNBinitiateddropIn-SyncFailureCase<Changeinformationclassificationinfooter>ProceduredescribeshoweNBdetectsthatanUEhasbeenlost–triggeredbydownlinktrafficeNBdetectsthatthetimealignmentoftheUEis“out-of-sync”(e.g.expirationoftimealignmenttimer)UEdetectsalsothatthetimealignmentisout-of-syncandreleasesitsPUCCHresourcesforCQIreportingandschedulingrequestand/orUEdetectsaradiolinkfailureandmovestoRRC_IDLEIfeNBdetectsDLdata(eitherdatatrafficorRRCsignalling)eNBsendsaPDCCHorderDCI1AtoUE(mayincludeseveralre-tries)UEwillnotrecognizethisPDCCHorderbecauseithasgonetoRRC_IDLEeNBrecognizesthattherandomaccessoftheUEwasnotsuccessful(UEdoesnotsendanyrandomaccesspreamble)andthatthe“in-sync”handlinghasfailedThiseventishandledasanewtriggerfortheradiolinkfailureprocedureeNBstartsasupervisiontimerT-RLFandtriggersUEContextReleaseaftertimerexpirationNote:byusingthesupervisiontimer,UEisabletoreturntocellviatheRRCConnecti