GSM原理介绍(英文版).pptx

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1、 NOKIA nokia.ppt/1/4/10/2023Agenda.GSM900/DCS1800 .The GSM Network&Air Interface .Technical Basics .Speech Coding .Types of Channel .Making a Phone Call NOKIA nokia.ppt/2/4/10/2023Global System for Mobile(Groupe Special Mobile)G S M NOKIA nokia.ppt/3/4/10/20231982 Groupe Special Mobile?is created wi

2、thin CEPT1986 A Permanent Nucleus is set up1987 Main radio transmission techniques are chosen,based on prototype evalution(1986)1989 GSM becomes an ETSI technical committe1990 The phase 1 GSM 900 specifications are finalized1991 First systems are running 1992 All major European GSM 900 operators beg

3、in commercial operator GSM Development History NOKIA nokia.ppt/4/4/10/2023 Speech Services Data Services Short Message Services(SMS)Supplementary Services Subscriber Identity Module(SIM)Security FunctionGSM/DCS1800 Functionalities NOKIA nokia.ppt/5/4/10/2023RF AspectsTDMA0.3GMSK ModulationBurst Powe

4、r TransmissionNeighbour Cells MeasurementHoppingUplink/Downlink DTxBER&Receiver Testing NOKIA nokia.ppt/6/4/10/2023GSM900/DCS1800/PCS1900 NOKIA nokia.ppt/7/4/10/2023GSM Frequency Range890-915 MHz Uplink/MS Transmit935-960 MHz Downlink/BS TransmitDuplex Offset 45 MHzChannel Spacing 200kHzChannel numb

5、ering 1-124Transmission Speed 270 Kbits NOKIA nokia.ppt/8/4/10/2023DCS1800 Frequency Range1710-1785 MHz Uplink/MS Transmit1805-1880 MHz Downlink/BS TransmitDuplex Offset 95 MHzChannel Spacing 200kHzChannel numbering 512-885Transmission Speed 270 Kbits NOKIA nokia.ppt/9/4/10/2023GSM Primary Band89090

6、0910920930940950960Freq45 MHzUplink(Mobile to Base)Downlink(Base to Mobile)NOKIA nokia.ppt/10/4/10/2023DCS1800 Primary Band1710 1735 1760 1785 1800 1825 1850 1875Freq95 MHzUplink(Mobile to Base)Downlink(Base to Mobile)NOKIA nokia.ppt/11/4/10/2023Carriers at the border of the GSM band890.2890.4890.68

7、90.8FreqGSM band200 kHz NOKIA nokia.ppt/12/4/10/2023Carriers at the border of the DCS1800 band1710.21710.41710.61710.8FreqDCS1800 band200 kHz NOKIA nokia.ppt/13/4/10/2023GSM NetworksBSCBTSBTSBTSBSSBSCBTSBTSBTSBSSMSCMSCOMCOMCADCNMCVLRVLRHLRAUCEIRInterface to other networkMS NOKIA nokia.ppt/14/4/10/20

8、23GSM NetworksTerminology:MS-Mobile Station(移动台移动台)BSS-Base Station System(基站系统基站系统)BTS-Base Transceiver Station(基站收发台基站收发台)BSC-Base Station Controller(基站控制器基站控制器)MSC-Mobile Switching Centre(移动业务交换中心移动业务交换中心)OMC-Operations and Maintenance Centre (操作与维护中心操作与维护中心)NMC-Network Management Centre(网络管理中心网络

9、管理中心)AUC-Authentication Centre(鉴权中心鉴权中心)HLR-Home Location Register(归属位置寄存器归属位置寄存器)VLR-Visitors Location Register (来访位置寄存器来访位置寄存器)EIR-Equipment Identity Register(设备标识寄存器设备标识寄存器)NOKIA nokia.ppt/15/4/10/2023MSCBSCBSCBSCPSTNBTSBTSBTSAir InterfaceAbis InterfaceSS#7SS#7GSM InterfaceMS NOKIA nokia.ppt/16/4

10、/10/2023GMSK Modulation1100 1 011001 0PSKGuassian FilterSpectrum 200kHz NOKIA nokia.ppt/17/4/10/2023FcFc+67.708KHzFc+67.708KHz+67.708KHz-67.708KHzData Type?0Data Type?1Modulation NOKIA nokia.ppt/18/4/10/2023401234567123456FrequencyAmplitudeARFCNTimeslotPhysical Channel isan ARFCN and TimeslotTDMA an

11、d FDMA NOKIA nokia.ppt/19/4/10/2023TDMA and FDMATerminology:FDMA -Frequency Division Multiple AccessTDMA -Time Division Multiple AccessARFCN -Absolute RF Channel NumberTS -TimeslotPhysical -The Combination of a TS number Channels and ARFCN.Logical -Are Mapped on Physical Channels Channels NOKIA noki

12、a.ppt/20/4/10/202310us10us10us10us8us8us3311575726 148 Active Bits,546.42us 147 Useful Bits542.8us-70dB-30dB-6dB+4dB-6dB-30dB-70dBTol-1.0dBTol+1.0dBGSM TDMA Power Burst NOKIA nokia.ppt/21/4/10/2023Power Time Template542.8 us/147 Bits1081010810TimePower-700dBUpper LimitLower LimitActualusNormal Burst

13、 NOKIA nokia.ppt/22/4/10/2023Power Time Template321.23 us/87 Bits 10 81010810TimePower-700dBUpper LimitLower LimitActualusAccess Burst87 bits NOKIA nokia.ppt/23/4/10/2023Uplink&DownlinkDownlink/MS Receive5670123456701342067012345671342Uplink/MS Transmit5 NOKIA nokia.ppt/24/4/10/2023Uplink&DownlinkAR

14、FCN0247360135061472531 264 572460357132104 5 6 7 01 23 4 5 6 7 00 34 5 67 0 1 2 3 4 51ARFCNUPLINKDOWNLINK45MHz.Uplink Lags Downlink by 3 Timeslot periods.Uplink and Downlink use same Timeslot Number.Uplink and Downlink use same Channel Number(ARFCN).Uplink and Downlink use different bands(45MHz apar

15、t for GSM900)NOKIA nokia.ppt/25/4/10/2023Frequency HoppingMODCouplerSwitchSynthRegisterControlUplink BS 1BS 2MonitoringRX LevRX QualDownlink 165124165124Home BS NOKIA nokia.ppt/26/4/10/202320ms BlocksSpeech CoderBits Ordered260 Bits260 Bits5013278.RELP and LTP Coder RELP-Residual-Excited Linear Pred

16、iction Coder LTP-Long Term Prediction.Converts Speech to Low Data Rate.20ms Speech makes 260Bits.Output 13kbit/sVery Important BitsImportant BitsOther BitsSpeech Coder NOKIA nokia.ppt/27/4/10/2023Error CorrectionType Ia 50Type Ib 132Type II 7850132783Type IaCRCType IbType IIBlock Code256625663478Re-

17、ordering37878Half rate convolutional code456 Bits from 20ms of SpeechType IaType IbType IbType IaTailType IICRC262 BitsIn456 BitsOut NOKIA nokia.ppt/28/4/10/2023Diagonal Interleaving456 Bits from 20ms of Speech456 Bits from 20ms of Speech575757575757575757575757575757575757 5757 5757 5757 575757 575

18、7 57TCHTraffic Channel(TCH)Bursts Carry Two 57 Bits Blocks(114)Each120ms of Speech=456x6=2736 bits2736/114=24 bursts I.e.24frames(mobile transmits once per frame)Multiframe has 26 frames in 120msThere are 2 spare frames厖厖 One SACCH,one Idle NOKIA nokia.ppt/29/4/10/2023Speech to Radio/Radio to Speech

19、ChannelcodingSpeechDigitizing and Source codingInterleavingBurst formatting CipheringModulationChanneldecodingSpeechSource decodingDe-interleavingBurst formatting DecipheringDemodulation NOKIA nokia.ppt/30/4/10/2023MS Camp on Flow ChartMS Turn OnMS searches channelsand orders by signalstrengthMSSton

20、gestBCCHFCCH on BCCH and adjusts timebaseSCH on BCCH and fine tunes timebase&timingDecode BCCH&store info Is BCCHin PLMN?MSNext StongestBCCHYESNOYESNONOLocation=Previous Location?YESYESMS camped on-listens for page,can request serviceUsing SACCH-adjust power,TA&report RX QualetcMS goes to the assign

21、ed SDCCH(Freq.,timeslot,.)for authentication+location UpdateMS sendsRACHBS assigns SDCCH to MS using the CCCH NOKIA nokia.ppt/31/4/10/2023Orignated CallBS pages MS usingthe CCCH MS sends RACHBS ORIGINATED CALLMS ORIGINATED CALLMS responds withRACH BS assigns MS to SDCCH or TCHMS transmits and receiv

22、es speech on TCHTCHUsing the FACCH onTCH authentication&location updateUsing the SDCCH,authentication,call setup,and TCH assignmentUsing the SACCH,BS commands MS to adust power+timing,MSreports power+Rx quality of BCCH+adjacent BCCHMS transmits+receives speechon TCHUsing the SACCH on TCH,MSreports p

23、ower+Rx quality,BScommands MS to adjust power,TADuring inactive timeslots,MS measures adjacent cells,BCCHCall disconnected by MS or BS NOKIA nokia.ppt/32/4/10/2023Subscriber Identity Module(SIM)Subscriber Identity Module(SIM)SIM contains(at least)following information:IMSI (International Mobile Subs

24、criber Identification)MCC&MNC (Mobile Country Code and mobile Network Code)Any other user specific information NOKIA nokia.ppt/33/4/10/2023International Mobile Subscriber Identity(IMSI)International Mobile Subscriber Identity(IMSI)IMSI=MCC+MNC+MSINNMSI3 digits2 digitsNot more than 15 digitsIMSI=Inte

25、rnational Mobile Subscriber IdentityMCC=Mobile Country CodeMNC=Mobile Network CodeMSIN=Mobile Station Identification NumberNMSI=National Mobile Subscriber Identity NOKIA nokia.ppt/34/4/10/2023International Mobile Equipment Identity(IMEI)International Mobile Equipment Identity(IMEI)IMEI=International Mobile Equipment IdentityTAC=Type Approval CodeFAC=Final Assembly CodeSNR=Serial NumberSP=SpareIMEI=TAC+FAC+SNRSP+6 digits2 digits6 digits1digit