GSM原理介绍(英文版)

Agenda.GSM900/DCS1800.TheGSMNetwork&AirInterface.TechnicalBasics.SpeechCoding.TypesofChannel.MakingaPhoneCallGlobalSystemforMobile(GroupeSpecialMobile)GSM1982 GroupeSpecialMobile?iscreatedwithinCEPT1986 APermanentNucleusissetup1987Mainradiotransmissiontechniquesarechosen,basedonprototypeevalution(1986)1989GSMbecomesanETSItechnicalcommitte1990Thephase1GSM900specificationsarefinalized1991Firstsystemsarerunning1992AllmajorEuropeanGSM900operatorsbegincommercial operatorGSMDevelopmentHistorySpeechServicesDataServicesShortMessageServices(SMS)SupplementaryServicesSubscriberIdentityModule(SIM)SecurityFunctionGSM/DCS1800FunctionalitiesRFAspectsTDMA0.3GMSKModulationBurstPowerTransmissionNeighbourCellsMeasurementHoppingUplink/DownlinkDTxBER&ReceiverTestingGSM900/DCS1800/PCS1900GSMFrequencyRange890-915MHzUplink/MSTransmit935-960MHzDownlink/BSTransmitDuplexOffset45MHzChannelSpacing200kHzChannelnumbering1-124TransmissionSpeed270KbitsDCS1800FrequencyRange1710-1785MHzUplink/MSTransmit1805-1880MHzDownlink/BSTransmitDuplexOffset95MHzChannelSpacing200kHzChannelnumbering512-885TransmissionSpeed270KbitsGSMPrimaryBand890900910920930940950960Freq45MHzUplink(MobiletoBase)Downlink(BasetoMobile)DCS1800PrimaryBand17101735176017851800182518501875Freq95MHzUplink(MobiletoBase)Downlink(BasetoMobile)CarriersattheborderoftheGSMband890.2890.4890.6890.8FreqGSMband200kHzCarriersattheborderoftheDCS1800band1710.21710.41710.61710.8FreqDCS1800band200kHzGSMNetworksBSCBTSBTSBTSBSSBSCBTSBTSBTSBSSMSCMSCOMCOMCADCNMCVLRVLRHLRAUCEIRInterfacetoothernetworkMSGSMNetworksTerminology:MS-MobileStation(移动台台)BSS-BaseStationSystem(基站系统统)BTS-BaseTransceiverStation(基站收发发台)BSC-BaseStationController(基站控制器器)MSC-MobileSwitchingCentre(移动业务交交换中心)OMC-OperationsandMaintenanceCentre(操作与维护护中心)NMC-NetworkManagementCentre(网络管理理中心)AUC-AuthenticationCentre(鉴权权中心)HLR-HomeLocationRegister(归属位位置寄存器器)VLR-VisitorsLocationRegister(来访访位置寄存存器)EIR-EquipmentIdentityRegister(设设备备标标识识寄寄存存器器)MSCBSCBSCBSCPSTNBTSBTSBTSAirInterfaceAbisInterfaceSS#7SS#7GSMInterfaceMSGMSKModulation110010110010PSKGuassianFilterSpectrum<200kHzFcFc+67.708KHzFc+67.708KHz+67.708KHz-67.708KHzDataType?0DataType?1Modulation401234567123456FrequencyAmplitudeARFCNTimeslotPhysicalChannelisanARFCNandTimeslotTDMAandFDMATDMAandFDMATerminology:FDMA-FrequencyDivisionMultipleAccessTDMA-TimeDivisionMultipleAccessARFCN-AbsoluteRFChannelNumberTS-TimeslotPhysical-TheCombinationofaTSnumberChannelsandARFCN.Logical-AreMappedonPhysicalChannelsChannels10us10us10us10us8us8us3311575726148ActiveBits,546.42us147UsefulBits542.8us-70dB-30dB-6dB+4dB-6dB-30dB-70dBTol-1.0dBTol+1.0dBGSMTDMAPowerBurstPowerTimeTemplate542.8us/147Bits1081010810TimePower-700dBUpperLimitLowerLimitActualusNormalBurstPowerTimeTemplate321.23us/87Bits1081010810TimePower-700dBUpperLimitLowerLimitActualusAccessBurst87bitsUplink&DownlinkDownlink/MSReceive5670123456701342067012345671342Uplink/MSTransmit5Uplink&DownlinkARFCN02473601350614725312645724603571321045670123456700345670123451ARFCNUPLINKDOWNLINK45MHz.UplinkLagsDownlinkby3Timeslotperiods.UplinkandDownlinkusesameTimeslotNumber.UplinkandDownlinkusesameChannelNumber(ARFCN).UplinkandDownlinkusedifferentbands(45MHzapartforGSM900)FrequencyHoppingMODCouplerSwitchSynthRegisterControlUplinkBS1BS2MonitoringRXLevRXQualDownlink165124165124HomeBS20msBlocksSpeechCoderBitsOrdered260Bits260Bits5013278.RELPandLTPCoderRELP-Residual-ExcitedLinearPredictionCoderLTP-LongTermPrediction.ConvertsSpeechtoLowDataRate.20msSpeechmakes260Bits.Output13kbit/sVeryImportantBitsImportantBitsOtherBitsSpeechCoderErrorCorrectionTypeIa50TypeIb132TypeII7850132783TypeIaCRCTypeIbTypeIIBlockCode256625663478Re-ordering37878Halfrateconvolutionalcode456Bitsfrom20msofSpeechTypeIaTypeIbTypeIbTypeIaTailTypeIICRC262BitsIn456BitsOutDiagonalInterleaving456Bitsfrom20msofSpeech456Bitsfrom20msofSpeech575757575757575757575757575757575757575757575757575757575757TCHTrafficChannel(TCH)BurstsCarryTwo57BitsBlocks(114)Each120msofSpeech=456x6=2736bits2736/114=24burstsI.e.24frames(mobiletransmitsonceperframe)Multiframehas26framesin120msThereare2spareframes厖OneSACCH,oneIdleSpeechtoRadio/RadiotoSpeechChannelcodingSpeechDigitizingandSourcecodingInterleavingBurstformattingCipheringModulationChanneldecodingSpeechSourcedecodingDe-interleavingBurstformattingDecipheringDemodulationMSCamponFlowChartMSTurnOnMSsearcheschannelsandordersbysignalstrengthMSStongestBCCHFCCHonBCCHandadjuststimebaseSCHonBCCHandfinetunestimebase&timingDecodeBCCH&storeinfoIsBCCHinPLMN?MSNextStongestBCCHYESNOYESNONOLocation=PreviousLocation?YESYESMScampedon-listensforpage,canrequestserviceUsingSACCH-adjustpower,TA&reportRXQualetcMSgoestotheassignedSDCCH(Freq.,timeslot,...)forauthentication+locationUpdateMSsendsRACHBSassignsSDCCHtoMSusingtheCCCHOrignatedCallBSpagesMSusingtheCCCHMSsendsRACHBSORIGINATEDCALLMSORIGINATEDCALLMSrespondswithRACHBSassignsMStoSDCCHorTCHMStransmitsandreceivesspeechonTCHTCHUsingtheFACCHonTCHauthentication&locationupdateUsingtheSDCCH,authentication,callsetup,andTCHassignmentUsingtheSACCH,BScommandsMStoadustpower+timing,MSreportspower+RxqualityofBCCH+adjacentBCCHMStransmits+receivesspeechonTCHUsingtheSACCHonTCH,MSreportspower+Rxquality,BScommandsMStoadjustpower,TADuringinactivetimeslots,MSmeasuresadjacentcells,BCCHCalldisconnectedbyMSorBSSubscriberIdentityModule(SIM)SIMcontains(atleast)followingin