LTE初始接入流程及參數(shù)

LTERandomAccessProcedureIndex2RandomAccessProcedure13TypicalLTEProcedures

Auth/Identity(Option)AttachProcedure(PoweronAttachComplete)

InitialContextSetup

RRCConnectionEstablishment

RandomAccess

CellcampOnUEeNBMMEMasterInformationBlockPoweronSystemInformationRandomAccessPreambleRandomAccessResponseRRCConnectionRequestRRCConnectionSetupRRCConnectionSetupComplete(AttachRequest)InitialUEMessageRequest(AttachRequest)RRCConnectionReconfigurationRRCConnectionReconfigurationCompleteAuthenticationRequestAuthenticationResponseSecurityModeCommandSecurityModeCompleteIdentityRequestIdentityResponseS1AP:InitialContextSetupRequest(AttachAccept)UECapabilityEnquiryUECapabilityInformationSecurityModeCommandRRCConnectionReconfiguration(AttachAccept)SecurityModeCompleteRRCConnectionReconfigurationCompleteULNASTransfer(AttachComplete)S1AP:InitialContextSetupResponseULNASTransport(AttachComplete)S1AP:UECapabilityInfoIndicationS1AP:DLNASTransport(AuthenticationRequest)S1AP:ULNASTransport(AuthenticationResponse)S1AP:DLNASTransport(IdentityRequest)S1AP:ULNASTransport(IdentityResponse)SRB0SRB1eNbS1AP:UEIdentityMMES1AP:UEIdentityeNbS1AP:UEIdentityMMES1AP:UEIdentityeNbS1AP:UEIdentityeNbS1AP:UEIdentityMMES1AP:UEIdentitySRB2andDRBDLNASTransport(SecurityModeCommand)ULNASTransport(SecurityModeComplete)MOCProcedure

InitialContextSetup

RRCConnectionEstablishment

RandomAccessUEeNBMMERandomAccessPreambleRandomAccessResponseRRCConnectionRequestRRCConnectionSetupRRCConnectionSetupComplete(ServiceRequest)InitialUEMessageRequest(ServiceRequest)

Auth/Identity(Option)S1APInitialContextSetupRequestUECapabilityEnquiryUECapabilityInformationSecurityModeCommandRRCConnectionReconfigurationSecurityModeCompleteRRCConnectionReconfigurationCompleteS1APInitialContextSetupResponseSRB0SRB1SRB2andDRB

DedicatedE-RABSetupControlS1APE-RABSetupRequestS1APE-RABSetupResponseRRCConnectionReconfigurationRRCConnectionReconfigurationCompleteDedicatedRB1……Option

DedicatedE-RABSetupControlS1APE-RABSetupRequestS1APE-RABSetupResponseRRCConnectionReconfigurationRRCConnectionReconfigurationCompleteDedicatedRB4ULInfoTransfer(BearerResourceAllocationRequest)ULNASTransport(BearerRARequest)IntraFrequencyHandover-intraeNBUEeNBMMES1-APINITIALUEMESSAGERRCConnectionReconfigurationMeasurementConfigurationRRCConnectionReconfigurationCompleteDefaultE-RABestablishmentandsecurityactivationMeasurementReportHODecisionRRCConnectionReconfigurationRandomAccessPreambleRandomAccessResponseRRCConnectionReconfigurationCompleteMeasurementConfiguration,MobilityControlInformation(RAPreambleIndex)RadioResourceConfigurationDedicated,

Securityinformation,UERelatedInformation(C-RNTI)ReleaseUEassociatedresourcesinthesourcecellRrcIntraEnbHo

T304

SwitchDLtoTargetcellStartreceivingULinTargetcellStartRRCintegrityprotectionwithnewkeyStartRRCandUPULdecipheringwithnewkeysStartRRCandUPDLcipheringwithnewkeysStarttransmittingDLintargetcellStartRRCintegrityprotectionwithnewkeyStartRRCandUPULcipheringwithnewkeysC-RNTI5eventsand2formsforrandomaccessprocedureInitialaccessfromRRC_IDLEAfterhandover,inthetargetcellULdataarrivalduringRRC_CONNECTEDDLdataarrivalduringRRC_CONNECTEDRRCConnectionRe-establishmentRandomAccessprocedureContentionbased(4steps)(5events)Non-contentionbased(3steps)(handoverandDLdataarrival)ContentionbasedorNon-contentionbasedduetoWhetherUEcanlistenPDCCH,andacquireradioresourcefromeNBforuplinktransformCONTENTIONBASEDRANDOMACCESSPROCEDURE:4stepsUEeNBMessage1:RandomAccessPreambleMessage2:RandomAccessResponseMessage3:ScheduledTransmission(UseHARQ)Message4:ContentionResolution(UseHARQ)PRACH:RA-RNTI（5bits）Preamblesequenceselect[0,numberOfRAPreambles]PDCCH,PDSCH:RA-RNTI,TemporaryC-RNTI,TA,ULGrantraResponseWindowSize

3thsubframePUSCH:TemporaryC-RNTI,UEidentifier(S-TMSI/Randomnumber)maxHARQmsg3TxpreambleTransMaxPDCCH,PDSCH:TemporaryC-RNTI,UEidentifier(S-TMSI/RN)maximumNumberOfDLTransmisionsRACHMessage4macContentionResolutionTimerPromoteTemporaryC-RNTItoaC-RNTIRadioResourceandparametersinSIB26RBs，1subframeRBG0,4RBsHybrid-AutomaticRepeatRequest(H-ARQ)Hybrid-AutomaticRepeatRequest(H-ARQ)reducesthedelayandincreasestheefficiencyofretransmissiondataSub-framenumberofRACHmessages1-3inTDDTDDFrameStructure(onlyconfig1,2aresupported)

Sub-framenumbersofRACHmessagesinTDDUEeNBMessage1Message2Message37ms7msRandomAccessPreamblemessageRAP選擇Zadoff-Chu序列的原因

具有很好的檢測性能，包括較高的檢測概率與較低的誤檢概率

正交序列的數(shù)量足夠多，保證足夠低的用戶沖突碰撞概率

能夠檢測到TA信息，要求序列在一定帶寬內(nèi)具有良好的相關(guān)性具有較低的峰均比特性Zadoff-Chu序列介紹目前RandomAccessPreamble只支持格式0與格式4.對于格式0，共有838個根ZC序列,每個根Zadoff-Chu序列的長度Nzc為839;對于格式4,共有138個根ZC序列,每個根Zadoff-Chu序列的長度Nzc,為139一個根Zadoff-Chu序列通過循環(huán)移位,可獲得多個正交的序列.循環(huán)移位大小Ncs決定了一個根ZC序列能產(chǎn)生多少個正交的序列,不同根Zadoff-Chu序列通過循環(huán)移位得到的序列并不一定正交一個LTE小區(qū)最多64個RandomAccessPreamble序列，來源于一個根Zadoff-Chu的循環(huán)移位或者多個根Zadoff-Chu序列的循環(huán)移位循環(huán)移位Ncs的設(shè)置小區(qū)半徑越大，信號時延擴展越大，需要較大的循環(huán)移位Ncs，每個根ZC產(chǎn)生的正交序列會較少；而RACH負荷較高的小區(qū)需要較小的循環(huán)移位Ncs來產(chǎn)生較多正交的序列，小區(qū)半徑受限PreambleformattransmissionwindowdurationMaximumcellradius01subframe14.53km12subframe77.34km23subframe29.53km34subframe100.16km4upPts1.4kmZadoff-Chu長度循環(huán)移位大小Ncs取值ZC序列經(jīng)過循環(huán)移位獲得正交序列數(shù)ZC根序列數(shù)量8391364.518392632.32839521648398310783910488RandomAccessFailure（FromUEView）UEMessage2:RandomAccessResponseraResponseWindowSizeexpiredMessage1:RandomAccessPreambleeNBUEMessage2:RandomAccessResponseMessage3:ScheduledTransmissionMessage4:ContentionResolutionmacContentionResolutionTimerexpiredMessage1:RandomAccessPreambleeNB??maxHARQmsg3TxPreambleTransMaxMessage1:RandomAccessPreambleMessage2:RandomAccessResponse?…..PL+preambleInitialReceivedTargetPower+PreambleTransmitPowerStepSize

…..Message3:ScheduledTransmissionMessage4:ContentionResolution?P0-Preamble+deltaPreambleMSG3+3dBPL+preambleInitialReceivedTargetPowerContentionResolutionfailsMaxHARQmsgTxReachedRandomAccessResponsefailsPreambleTransMaxReachedFailureToSetupTheRRCConnection（FromeNBView）Message3：RRCConnectionRequestUEMessage2:RandomAccessResponseMessage1:RandomAccessPreambleeNBRRCConnectionRejectWaitTimeeNBfailuretosetuptheRRCConnectionTheUEbacksoffforacertainperiodoftimeselectedrandomlyintherange[0,rABackoff],thenrestartstheprocedureRRCProcedureDefenceTimerExpiredIftheeNBdoesnotreceiveRRCCONNECTIONSETUPCOMPLETEbeforethetimerexpiry,theRRCconnectionisconsideredasfailedMessage3：RRCConnectionRequestUEMessage2:RandomAccessResponseMessage1:RandomAccessPreambleeNBRRCConnectionSetupRRCProcedureDefenceTimerExpiredRRCConnectionSetupCompleteMessage3PowerMPUSCH(I):

isthebandwidthoftheMsg3transmissioninsubframeiexpressedinnumberofresourceblocksP0_PUSCH(2)=P0_UE_PUSCH(2)+P0_NORMINAL_PUSCH(2)P0_NORMINAL_PUSCH(2)=P0_PREAMBLE+ΔPREAMBLE_Msg3=P0_PREAMBLE+3

α(2)=1ΔTF(i)=0f(0)=

(Npreamble-1)*ΔRAMP_UP+(TPCinMsg2)

=4dBConfiguredbytPCRACHMsg3

Msg1andMsg3POWERMessage1Power

P0_PREAMBLE=SINRTarget+IN+MARGIN(configuredbypreambleInitialReceivedTargetPower)

CONTENTIONBASEDRANDOMACCESSPROCEDURE:3stepsUEeNBMessage0(PDCCHOrder):RAPreambleAssignmentMessage1:RandomAccessPreambleMessage2:RandomAccessResponsesourceeNB(handover)orPDCCH(dataarrival)RAPreambleindex<>0PRACH:RA-RNTIPDCCH,PDSCH:RA-RNTI,TA,

ULgrant[64-numberOfRAPreambles,numberOfRAPreambles]receptionOfMsg1TimerPdcchOrderTransMaxRandomAccessFailureAfteracertainnumberofattempts(configuredbyparameterpreambleTransMax),

theMAClayerdeclarestheRandomAccessprocedureasfailedpreambleTransMaxParametersParameterObjectRange&UnitClass/CategoryDefaultValuecontentionFreeRACHenabledENBEquipment/Enb/LteCell/CellRachConfBooleanTrue/FalseB--Cell/FixedTRUEnumberOfRAPreamblesENBEquipment/Enb/LteCell/CellRachConfInteger[56..64]step=4B--Cell/Fixed56raResponseWindowSizeENBEquipment/Enb/LteCell/CellRachConfEnumerate{sf2(0),sf3(1),sf4(2),sf5(3),sf6(4),sf7(5),sf8(6),sf10(7)}B--Cell/FixedSf8preambleTransMaxENBEquipment/Enb/LteCell/CellRachConfEnumerate{n3(0),n4(1),n5(2),n6(3),n7(4),n8(5),n10(6),n20(7),n50(8),n100(9),n200(10)}C--Immediate-propagation/Fixedn3(0)macContentionResolutionTimerENBEquipment/Enb/LteCell/CellRachConfEnumerate{sf8(0