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1、1上海大唐移动通信设备有限公司2003.12GSMGSM移动通信系统原理培训讲义移动通信系统原理培训讲义无线接口信令协议无线接口信令协议 2Um Um 接接 口口 信信 令令3GSM系统专用协议群DTAPDTAP Direct Transfer Application PartBSSMAP BSS Management Application PartCM Call ManagementMM Mobile ManagementRR Radio Resource ManagementSCCP Signalling Connection Control PartMAP Mobile Applica
2、tion PartTCAP Transaction Capability Application PartISUP ISDN User PartMTP Message Transfer PartCMMMRRSig. layer 2Layer 1 (air)Sig. layer 2Sig. layer 1MTPSCCPBSSMAPRR(CM+MM)MSBSCMTPMTPSCCPSCCPCMMMBSSMAPTCAPMAPISUPMSCSig. layer 2Layer 1 (air)BTS(CM)(MM)(RR)(CM)(MM)(RR)(CM)(MM)(LAPDm)(LAPDm)(LAPD)Sig
3、. layer 2Sig. layer 1(LAPD)BTSMBTSMRRBTSM BTS ManagementUm InterfaceAbis InterfaceA-interfaceInter-MSCInterface4Channel RequestEstablishment Cause emergency callCall re-establish Location update Answer to paging: same as channel needed in Paging NECI=0: MO&procedure be complete with SDCCH NECI=1: MO
4、 TCH/F Procedure be complete with SDCCHRandom Reference立即指配流程MSBSSCHANNEL REQUEST(1)IMMEDIATE ASSIGNMENT(EXTENDED)Immediate AssignmentL2 Pseudo lengthProtocol discriminator Skip indicationMessage type-N(SD) for MS side Page modeChannel descriptionRandom referenceTiming advanceMobile allocationStarti
5、ng timeIA rest octetsT3126MMRRCHANNEL REQUEST(2M+1)IMMEDIATE ASSIGNMENT REJECTSABM(L3) (1)UA(L3)SABM(L3) (26) Protocol discriminatorCall control;call related SS messagesMobility management messagesRadio resource management messagesPage modeNormal pagingExtended pagingPaging reorganizationSame as bef
6、oreChannel descriptionChannel type and TDMA offset SDCCH/8+SACCH/8+subchannel SDCCH/4+SACCH/4+subchannel TCH/F+ACCHTNTSCHopping channel single channel:ARFCN RF hopping channel:HSN+MAIORequest referenceRandom Access InformationT1/T2/T3FNT1=(FN/1326)mod 32T2=(FN)mod 26T3=(FN)mod 51(FN)mod 42432=51x(T3
7、-T2)mod 26)+T3+51x26xT1Mobile allocationIndex for CAStarting timeT1/T2/T3IA rest octetsMAIO+Mobile allocation(frequency parameters before time)Immediate Assignment ExtendedPage modeChannel description1Random reference1Timing advance1Channel description2 Request reference2Timing advance2Mobile alloca
8、tionStarting timeIA rest octetsImmediate Assignment RejectPage modeRandom reference1Waiting Indication1Random reference2Waiting Indication2Random reference3Waiting Indication3Random reference4Waiting Indication4Waiting IndicationT3122:0255 secondSS+T-10max(8,T)-1T3101T200:235msMM要求进入专有模式RR响应寻呼允许接入网络
9、T3122T3126:T+2S5 secondRACHRACHAGCHAGCHSDCCHSDCCHSDCCH5Paging Request Type1Paging modeChannel needed for mobile1Mobile identity1(IMSI/TMSI)Channel needed for mobile2Mobile identity2(IMSI/TMSI)寻呼流程MSBSSPAGING REQUEST TYPE1/2/3PAGING REQUEST TYPE 1/2/3CHANNEL REQUESTIMMEDIATE ASSIGNMENT(EXTENDED)SABM(
10、Paging response)UA(Paging response)Paging Request Type2Paging modeChannel needed for mobile1Mobile identity1(TMSI)Channel needed for mobile2Mobile identity2(TMSI)Channel needed for mobile3Mobile identity3(IMSI/TMSI)Paging Request Type3Paging modeChannel needed for mobile1Mobile identity1(TMSI)Channe
11、l needed for mobile2Mobile identity2(TMSI)Channel needed for mobile3Mobile identity3(TMSI)Channel needed for mobile4Mobile identity4(TMSI)PCHPCHAGCHAGCHSDCCHSDCCHT3113Paging ResponseCiphering key sequenceMobile station classmark 2MS identity(IMSI/TMSI)Classmark Information 2Phase1/Phase2 MSControlle
12、d Early Classmark Sending RF Power CapabilityPseudo Synchronization CapabilitySupplementary Service Screening IndicationMT SMS pt. To pt. CapabilityFrequency Capability(GSM900 Extended?)A5/1;A5.2;A5/3Classmark 3 6Measurement reportBA-usedDTX-usedMeas-validRxlev_full/sub(serving cell)Rxqual_full/sub(
13、serving cell)NO-NCELL-MRxlev(neighbor cell 16)BCCH-Freq-Ncell(16)BSIC-Ncell(16)SACCH流程MSBSSSYSTEM INFORMATION 5/5bis/5ter/6MEASUREMENT REPORTSACCH Downlink L1 HeaderOrdered MS power levelOrdered timing advanceSACCH Uplink L1 HeaderActual MS power levelActual timing advanceSYSTEM INFORMATION 5/5bis/5
14、ter/6MEASUREMENT REPORTSACCHSACCHSACCHSACCH7ASSIGNMENT COMMANDChannel descriptionPower commandCell channel descriptionStarting time Mobile allocation(after time)Mobile allocation(before time)Channel mode指配流程MSBSSASSIGNMENT COMMANDASSIGNMENT FAILUREUASABM(1)SDCCHSDCCHFACCHFACCHASSIGNMENT COMPLETESABM
15、(26)ASSIGNMENT FAILURET3107FACCHFACCHSDCCHASSIGNMENT COMPLETEASSIGNMENT FAILURERR CauseRR CauseNormal eventAbnormal release,unspecifiedAbnormal release,channel unacceptableAbnormal release,timer expiredAbnormal release,no activity on radio pathPreemptive releaseHandover impossible,timing advance out
16、 of rangeChannel mode unacceptableFrequency not implementedCall already clearedSemantically incorrect messageInvalid mandatory informationMessage type non-existent or not implementedMessage type not compatible with protocol stateConditional IE errorNo cell allocation availableProtocol error unspecif
17、iedChannel modeSignalling onlySpeech full rate version1Speech full rate version2Data,14.5kbps radio interface rateData,14.5kbps radio interface rateData,12.0kbps radio interface rateData,6.0kbps radio interface rateData,3.6kbps radio interface rate8HANDOVER CommandCell descriptionChannel description
18、Handover referencePower command and access typeCell channel descriptionMobile allocation(after time)Channel modeTiming AdvanceSynchronization indication(伪/预)同步切换流程MSBSSHANDOVER COMMANDSDCCH/FACCHSABMT3103Cell DescriptionBCCH ARFCNBCCNCCBSSHANDOVER ACCESSHANDOVER ACCESSHANDOVER ACCESSHANDOVER ACCESSS
19、ABMUAHANDOVER COMPLETEHANDOVER FAILURESDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHPower Command and Access TypePower levelAccess type control:Sending Handover access is mandatory or optional Synchronization IndicationReport observed timing diffe
20、rence: shall be include in Handover complete or notOTD=RTD+t1-t0Synchronization indication: non-synchronized synchronized pre-synchronized pseudo-synchronizedNormal cell indication: TA63 is ignored TA63 trigged handover failure HANDOVER Failure/CompleteRR CauseMobile observed time differenceRR Cause
21、Normal eventProtocol error unspecified Handover impossible,timing advance out of rangeChannel mode unacceptableFrequency not implementedHANDOVER FAILUREUA9HANDOVER CommandCell descriptionChannel descriptionHandover referencePower command and access typeCell channel descriptionMobile allocation(after
22、 time)Channel modeTiming AdvanceSynchronization indication非同步切换流程MSBSSHANDOVER COMMANDSDCCH/FACCHSABMT3103BSSHANDOVER ACCESS(1)HANDOVER ACCESS(n)SABMUAHANDOVER COMPLETEHANDOVER FAILURESDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHPhysical Informat
23、ionTAPHYSICAL INFORMATION(1)PHYSICAL INFORMATION(2Ny1)T3105T3124:675ms(SDCCH),320ms(TCH)HANDOVER FAILUREUASDCCH/FACCHSDCCH/FACCH10连接释放流程MSBSSCHANNEL RELEASE(DEACTIVE SACCH)DISCUASDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHDISC(26)T3109Channel ReleaseRR CauseBA rangeT3110:240470msT3111=T3110RR CauseN
24、ormal eventAbnormal release,unspecifiedAbnormal release,channel unacceptableAbnormal release,timer expiredAbnormal release,no activity on radio pathPreemptive releaseNo cell allocated availableProtocol error unspecified11Frequency RedifinitionChannel descriptionMobile allocationStarting timeCell cha
25、nnel description无线资源管理其他流程MSBSSFREQUENCY REDEFINITIONRR STATUSCHANNEL MODE MODIFYSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHSDCCH/FACCHCHANNEL MODE MODIFY ACKCIPHERING MODE COMPLETESDCCH/FACCHSDCCH/FACCHSDCCH/FACCHCipher Mode SettingA5/0A5/7CIPHERING MODE COMMANDCLASSMARK ENQUIRYCLASSMARK CHANGERR StatusRR ca
26、useChannel Mode Modify (ACK) Channel descriptionChannel modeCipher ResponseIMEISV(IMEI+Software Version) shall be included or notClassmark Information 2Phase1/Phase2 MSControlled Early Classmark Sending RF Power CapabilityPseudo Synchronization CapabilitySupplementary Service Screening IndicationMT
27、SMS pt. To pt. CapabilityFrequency Capability(GSM900 Extended?)A5/1;A5.2;A5/3Classmark 3 Classmark Information 3Multi-bands supported,E-GSM/DCS1800/R-GSMRF Power Capability for each bandA5/4,A5/5,A5/6,A5/7UCS2CIPHERING MODE COMMANDCipher mode settingCipher responseCiphering Mode CompleteIMEISVClassm
28、ark ChangeClassmark 2Classmark 312TMSI重分配流程MSBSSTMSI REALLOCATION COMMANDTMSI REALLOCATION COMPLETESDCCH/FACCHSDCCH/FACCHT3250TMSI Reallocation CommandLAI=MCC+MNC+LACTMSI13鉴权流程MSBSSAUTHENTICATION REQUESTAUTHENTICATION RESPONSESDCCH/FACCHSDCCH/FACCHT3260:12sAuthentication RequestCiphering key sequenc
29、e number:06Authentication parameter RAND:128bitsAuthentication ResponseAuthentication parameter SRES:32bitsAUTHENTICATION REJECTT3240:10sSDCCH/FACCHIDLE(No IMSI,roaming not allowed)14身份确认流程MSBSSIDENTITY REQUESTIDENTITY RESPONSESDCCH/FACCHSDCCH/FACCHT3270:12sIdentity RequestIdentity type:IMSI/IMEI/TM
30、SI/IMEISVIdentity ResponseMobile Identity15IMSI分离流程MSBSSIMSI DETACH INDICATIONSDCCH/FACCHT3220:5sIMSI Detach IndicationMobile station classmark 1Mobile IdentityMobile Station Classmark 1Phase1/Phase2 MSControlled Early Classmark Sending RF Power CapabilityA5/1;16AbortReject cause移动管理其他流程MSBSSABORTSD
31、CCH/FACCHMM InformationFull name for networkShort name for networkNetwork time zoneNetwork time and time zoneReject CauseIllegal MSNetwork failureIDLE(if illegal MS,No IMSI,roaming not allowed)MM INFORMATIONMM STATUSMM StatusReject causeReject CauseMessage type non-existent or not implemented17位置更新流
32、程MSBSSLOCATION UPDATE REQUEST (1)SDCCH/FACCHSDCCH/FACCHLocation Update RequestLocation update typeCiphering key sequence numberLocation area identificationMobile Station classmark 1Mobile identityLocation Update TypeLUT:Normal location updatePeriod location updateIMSI attachFOR:(no)follow-on request
33、 pendingLOCATION UPDATE ACCEPTT3212SDCCH/FACCHIDLE(No IMSI,roaming not allowed)LOCATION UPDATE REJECTLOCATION UPDATE REQUEST(2)Location Update AcceptLocation area identificationMobile identityFollow-on proceedLocation Update RejectReject causeT3210:20sLOCATION UPDATE REQUESTT3211:15sTMSI REALLOCATIO
34、N COMPLETET3250:12sT3240:10s(wait for RR release)LOCATION UPDATE REQUEST(34)Reject CauseIMSI unknown in HLRIllegal MSIllegal MEPLMN not allowedLocation Area not allowedRoaming not allowed in this location areaMandatory information element error Protocol error,unspecifiedInformation element not exist
35、 or not implementedConditional IE error18移动管理连接建立流程MSBSSSABM(CM SERVICE/RE-EST REQUEST 1)CM Service RequestCM service typeCiphering key sequence numberMobile station classmark 2Mobile identityUA(CM SERVICE/RE-EST REQUEST)T3230:15sCM SERVICE ACCEPTT3240:10s(wait for RR release)SABM(CM SERVICE/RE-EST
36、REQUEST24)Reject CauseIMSI unknown in VLRIllegal MENetwork failureCongestionService option not supportedRequested service option not subscribedService option temporarily out of orderCM SERVICE REJECTCM Service TypeMobile originating call establishmentEmergency call establishmentShort message service
37、 Supplementary service activationCM SERVICE ABORTAUTHENTICATION REQUESTCM Re-establishment RequestCiphering key sequence numberMobile station classmark 2Mobile identityLocation area identificationCM Service RejectReject cause19Emergency SetupProtocol DiscriminatorTransaction IdentifierMessage Type-N
38、(SD) for MS SideBearer capability移动主叫呼叫建立流程MSBSSCM SERVICE/RE-EST REQUESTSetupBearer capabilityFacility(only used for SS)Called party BCD numberSS versionCLIR suppressionCLIR invocationCall control capability(DTMF support)T303:30sCM SERVICE ACCEPTSETUP/EMERGENCY SETUPBearer capabilityInformation tra
39、nsfer capability:SpeechDataFacsimile group 3Alternate speech/facsimile group 3,speech startTransfer mode: Circuit mode/Packet modeCoding standard:GSM standardized CodingRadio channel requirement: Full rate/Dual rate, full rate prefer/Dual rate, half rate prefer Speech version indication: FR/EFR/HR a
40、ll supported be included in order of preference CALL PROCEEDINGALERTINGRELEASE COMPLETEDISCONNECTCONNECTCONNECT ACKCall Proceeding/Alerting/ConnectFacilityProgress indicatorRelease Complete/DisconnectCauseFacilitySS versionProgress indicatorCoding stardard:Standard defined for the GSMPLMNS as descri
41、bed belowLocation:Private network serving the local userPublic network serving the local userPublic network serving the remote userPrivate network serving the remote userNetwork beyond interworking pointProgress description:Call is not end-to-end PLMN/ISDN, further call progress information may be a
42、vailable in-bandDestination address in non-PLMN/ISDNOrigination address in non-PLMN/ISDNCall has returned to the PLMN/ISDNIn-band information or appropriate pattern now availableCall is end-to-end PLMN/ISDNQueueing Unspecific CauseCoding standard:same as Progress indicatorLocation:same as Progress i
43、ndicatorCause valuenormal event class 1normal event class 2resource unavailableservice or option not availableservice or option not implementedinvalid message (e.g. parameter out of range)protocol error (e.g. unknown message) interworkingT310:30sT313:30sT313DISCONNECTTransaction IdentifyTI flag:0-me
44、ssage is send from the side that originates the TI1-message is send to the side that originates the TI TI value:06,given PD,given SAP,distinguish different message flow20移动被叫呼叫建立流程MSBSSPAGING RESPONSESetupBearer capabilityFacility(only used for SS)Calling party BCD numberProgress indicatorSignalSETU
45、PRELEASE COMPLETESignaldial tone onring back tone onintercept tone onnetwork congestion tone onbusy tone onconfirm tone onanswer tone oncall waiting tone onoff-hook warning tone ontones offalerting offDISCONNECTCONNECT ACKCall ConfirmBearer capabilityCauseCall control capabilityT310T313:30sDISCONNEC
46、TCALL CONFIRMEDALERTINGCONNECTT303T301:180sALERTING/CONNECTFacilitySS version21呼叫其他流程MSBSSProgressProgress indicatorPROGRESSNotification IndicatorUser suspendedUser resumedBearer changeSTATUSNOTIFYMODIFYMODIFY COMPLETEMODIFY REJECTNotifyNotification indicatorCall State nullconnection pendingCC promp
47、t presentWait for network informationCC-Establishment presentCC-Establishment confirmed Recall present call initiated mobile originating call proceedingcall delivered call present call received connect request mobile terminating call confirmed active disconnect request disconnect indication release
48、request mobile originating modify mobile terminating modify connect indicationStatusCauseCall stateAuxiliary statesAuxiliary StateHold auxiliary state idle hold requestcall held retrieve requestMulti party auxiliary state idleMPTY requestcall in MPTYsplit requestModify/Modify CompleteBearer capabili
49、tyModify RejectBearer capabilityCauseHOLDHOLD ACKNOWLEDGEHOLD REJECTRETRIEVERETRIEVE ACKNOWLEDGERETRIEVE REJECTHold Reject/Retrieve RejectCause22DTMF流程MSBSSSTART DTMFStart DTMF(ACK)Keypad facilitySTART DTMF ACKSTOP DTMFSTOP DTMF ACKStart DTMF RejectCause23呼叫释放流程MSBSSDISCONNECTRELEASERELEASE COMPLETE
50、DISCONNECTRELEASERELEASE COMPLETET305:30sT308RELEASET308:30sRELEASERELEASET305:30sRELEASERELEASET308RELEASET308:30sRELEASEDISCONNECTRELEASE COMPLETERELEASEReleaseCauseseconde causeFacilitySS versionT306:30sT30824Um接口信令流程(早分配)Originated MSTerminated MSICM service acceptIAssignment CommandSABMCM_Servi
51、ce_ReqUIPaging Request Type 1/2/3NetworkChannel RequestUACM_Service_ReqUIImmediate AssignmentRRUISystem Info 5/6UIMeasurement ReportISETUPRRICall ProceedingUISystem Info 5/6UIMeasurement ReportRRChannel RequestUIImmediate AssignmentSABMPaging ResponseUAPaging ResponseRACHAGCHSDCCHSDCCHSDCCHSDCCHSACC
52、HSACCHSDCCHSDCCHSDCCHSACCHSACCHSDCCHSDCCHPCHRACHAGCHSDCCHSDCCHRRSDCCH25Originated MSTerminated MSUISystem Info 5/6IAlertingIAssignment CompleteISetupNetworkSABMRRUAUIMeasurement ReportUISystem Info 5/6UIMeasurement ReportRRRRIAssignment CommandUISystem Info 5/6UIMeasurement ReportICall ConfirmedRRRR
53、SABMUAIAssignment CompleteRRIAlertingRRUISystem Info 5/6UIMeasurement ReportFACCHFACCHFACCHFACCHSACCHSACCHSACCHSACCHFACCHFACCHFACCHFACCHFACCHSACCHSACCHSDCCHSDCCHFACCHFACCHFACCHSDCCHSDCCHSACCHSACCHSDCCHSDCCHUm接口信令流程(早分配)26Originated MSTerminated MSRRRRRRNetworkIConnectIConnect ACKIConnectIConnect ACK
54、RRUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportSACCHSACCHFACCHFACCHFACCHFACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHF
55、ACCHFACCHFACCHFACCHSACCHUm接口信令流程(早分配)27Originated MSTerminated MSRRRRRRNetworkIDisconnectIReleaseIDisconnectIReleaseRRUISystem Info 5/6UIMeasurement ReportUAIRelease CompleteRRUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportIChannel Rele
56、aseRRDISCRRIRelease CompleteRRIChannel ReleaseDISCUASACCHSACCHFACCHFACCHFACCHFACCHSACCHSACCHSACCHSACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHSACCHFACCHFACCHFACCHFACCHFACCHSACCHFACCHFACCHUm接口信令流程(早分配)28信令流程(特别早分配)Originated MSTerminated MSICM service acceptIChannel Mode ModifySABMCM_Service_Req
57、UIPaging Request Type 1/2/3NetworkChannel RequestUACM_Service_ReqUIImmediate AssignmentRRUISystem Info 5/6UIMeasurement ReportISETUPRRICall ProceedingUISystem Info 5/6UIMeasurement ReportRRChannel RequestUIImmediate AssignmentSABMPaging ResponseUAPaging ResponseRACHAGCHFACCHFACCHFACCHFACCHSACCHSACCH
58、FACCHFACCHFACCHSACCHSACCHFACCHFACCHPCHRACHAGCHFACCHFACCHRRFACCH29Originated MSTerminated MSUISystem Info 5/6IAlertingIChannel mode Modify ACKISetupNetworkRRUIMeasurement ReportUISystem Info 5/6UIMeasurement ReportRRRRIChannel Mode ModifyUISystem Info 5/6UIMeasurement ReportICall ConfirmedRRRRIChanne
59、l Mode Modify ACKRRIAlertingRRUISystem Info 5/6UIMeasurement ReportFACCHFACCHSACCHSACCHSACCHSACCHFACCHFACCHFACCHFACCHSACCHSACCHFACCHFACCHFACCHFACCHFACCHFACCHSACCHSACCHFACCHFACCH信令流程(特别早分配)30Originated MSTerminated MSRRRRRRNetworkIConnectIConnect ACKIConnectIConnect ACKRRUISystem Info 5/6UIMeasuremen
60、t ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportSACCHSACCHFACCHFACCHFACCHFACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHSACCHFACCHFACCHFACCHFACCHSACCH信令流程(特别
61、早分配)31Originated MSTerminated MSRRRRRRNetworkIDisconnectIReleaseIDisconnectIReleaseRRUISystem Info 5/6UIMeasurement ReportUAIRelease CompleteRRUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportUISystem Info 5/6UIMeasurement ReportIChannel ReleaseRRDISCRRIRelease CompleteRRICh
62、annel ReleaseDISCUASACCHSACCHFACCHFACCHFACCHFACCHSACCHSACCHSACCHSACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHFACCHSACCHFACCHFACCHFACCHFACCHFACCHSACCHFACCHFACCH信令流程(特别早分配)32UmUm接口数据链路层协议接口数据链路层协议LAPDmLAPDm33GSM系统专用协议群DTAPDTAP Direct Transfer Application PartBSSMAP BSS Management Application PartCM Ca
63、ll ManagementMM Mobile ManagementRR Radio Resource ManagementSCCP Signalling Connection Control PartMAP Mobile Application PartTCAP Transaction Capability Application PartISUP ISDN User PartMTP Message Transfer PartCMMMRRSig. layer 2Layer 1 (air)Sig. layer 2Sig. layer 1MTPSCCPBSSMAPRR(CM+MM)MSBSCMTP
64、MTPSCCPSCCPCMMMBSSMAPTCAPMAPISUPMSCSig. layer 2Layer 1 (air)BTS(CM)(MM)(RR)(CM)(MM)(RR)(CM)(MM)(LAPDm)(LAPDm)(LAPD)Sig. layer 2Sig. layer 1(LAPD)BTSMBTSMRRBTSM BTS ManagementUm InterfaceAbis InterfaceA-interfaceInter-MSCInterface34LAPDm包括下列功能包括下列功能/a) 在Dm信道上提供一个或多个数据链路连接。数据链路连接之间是利用包含在各帧中的数据链路连接标示符来
65、加以区别；/b) 允许帧类型的识别；/c) 顺序控制，以保持通过数据链路连接的各帧的次序；/d) 检测一数据链路连接上的帧格式差错和操作差错；/e) 把不能修复的差错通知管理实体；/f) 流量控制/g) 竞争建链LAPDm 功能35 LAPDm协议协议（ UmUm接口接口第二层第二层,GSM04.05 04.06）/操作模式/非证实模式(Unacknowledged mode)/第三层消息采用无编号帧又称UI帧(Unnumbered Information frame)发送/接收方对UI帧无须确认/不提供流量控制机制和错误恢复机制/证实模式(Acknowledged mode)/该模式采用多帧
66、操作方式/第三层消息采用编号帧又称I帧(numbered Information frame)发送/接收方需要对I帧进行确认/顺序控制,保证对方第三层接收的消息次序与本方第三层提交的次序相同/提供流量控制机制和错误恢复机制36LAPDm协议协议（ UmUm接口接口第二层）第二层）/LAPDm与第一层和第三层的接口37LAPDm协议协议（ UmUm接口接口第二层）第二层）/操作模式与信道的关系38LAPDm协议协议（ UmUm接口接口第二层）第二层）/帧格式地址域控制域长度域填充比特.地址域控制域长度域填充比特.信息域.信息域.类型 A类型 B类型 Bbis/类型A:在DCCH上,当没有第三层消
67、息要发,作为没有信息域的填充帧,长度域设为0./类型B:用于在DCCH上发送第三层消息,长度域设为信息域的长度/类型Bbis:用于在BCCH/PCH/AGCH上发送第三层消息长度=3长度=N201长度=3长度=N201长度=N20139LAPDm协议协议（ UmUm接口接口第二层）第二层）/填充比特：0x2B/填充帧当无线上必须发送而没有L3消息要发时，应发填充帧。Fill frame for DCCH:40LAPDm协议协议（ UmUm接口接口第二层）第二层）/地址域格式:Spare=0,LPD=00/01（01用于广播短消息）,SAPI=0/3（3用于短消息）41LAPDm协议协议（ Um
68、Um接口接口第二层）第二层）/控制域格式/长度域格式：M=1表示该帧仅含第三层消息的一部分，M=0表示该帧含有一条完整的第三层消息或第三层消息的最后一部分。P/F：当该消息为命令时，该比特为P比特，表示询问（Polling)比特,置“1”要求对方予以响应；当该消息为响应时，该比特为F比特，表示最后（Final)比特，置“1”表示该响应是在对方要求下回的。42LAPDm协议协议（ UmUm接口接口第二层）第二层）/帧类型（仅适用于DCCH）/I帧：N(S)为发送序号，N(R)为接收序号，V(S)为发送状态变量，表示下一次要发送的I帧的序号，V(A)为确认状态变量，表示发送序号为V(A)-1的I帧
69、已被对方确认，V(R)为接收状态变量，表示期望对方下一个I帧的发送序号为V(R)。对N(S)、N(R)、V(S)、V(R)和V(A)的操作均为模8操作。/监视帧/RR帧:用于对已接收的发送序号为N（R）-1的I帧进行确认/REJ帧:用于要求对方重发发送序号为N（R）的I帧/RNR帧:用于通知对方本方忙，不能继续接收I帧/无编号帧/SABM帧:用于设置接收方为多帧证实模式/DISC帧:用于设置接收方退出多帧证实模式/UA帧:用于通知对方已接收到SABM或DISC/UI帧/DM帧:用于通知接收方发送方不能保持在多帧证实模式43LAPDm协议协议（ UmUm接口接口第二层）第二层）/建立多帧操作模式
70、/竞争下的建链方式该情况对应于移动台在RACH上发信道请求，网络在AGCH上给立即指配，由于可能有多个移动台几乎同时发信道请求，且它们使用的随机参考值相同，虽然网络只检测到一个移动台的信道请求，但其他移动台可能也会认为立即指配是发给自己的，它们也会到指定的DCCH信道进行建链，此时就发生了竞争。LAPDm协议通过采用竞争下的建链机制来解决这个问题。具体方法如下：/规定必须由移动台发起建链（发SABM帧），该SABM帧带有信息域，信息域中为一条第三层消息（CM业务请求、寻呼响应、位置更新请求或IMSI DETACH）,并启动T200定时器。/网络在收到该SABM后，回UA帧，该UA也带有信息域，
71、信息域中所带第三层消息与SABM中的第三层消息完全相同。/由于所带第三层消息含移动台的身份识别（IMSI、TMSI等），该身份识别具有唯一性，移动台检查收到的UA中所含第三层消息与自己在SABM中发的第三层消息完全相同才可以认为建链成功，若发现不同，应认为建链失败，并离开该信道进入空闲状态。若T200定时器超时仍未检测到UA，则重发SABM，当重发N200次后，应会到空闲状态。44LAPDm协议协议（ UmUm接口接口第二层）第二层）/建立多帧操作模式/正常下的建链方式该情况对应于移动台由SDCCH收到网络的指配命令转到FACCH上建链或在SAPI=0链路建立好后建立SAPI=3的链路等。由于
72、不存在竞争情况，因此采用正常建链方式。具体方法如下：/可以由网络或移动台发起建链（发SABM帧），该SABM帧不带信息域。/对方在收到该SABM后，回UA帧，该UA也不带信息域。/建链（发SABM回UA）的目的是使双方进入一个已知的初始状态，即V(S)、V(A)和V(R)均为0，清除I帧发送队列和接收队列。这样就为下面的多帧传送做好了准备。45LAPDm协议协议（ UmUm接口接口第二层）第二层）/终止多帧操作模式/正常释放/若收到第三层的释放链路命令“Release request-normal release”,由数据链路层发DISC帧，该DISC帧不带信息域。/对方在收到该DISC后，用
73、“Release indication”向第三层汇报，并回UA帧，该UA也不带信息域。/收到对方的UA后，用“Release confirm”向第三层报告。/该方式主要用于在某个DCCH信道上需要终止多帧操作模式，且不需要在后续的DCCH信道上建立多帧操作模式。/本地释放/若收到第三层的释放链路命令“Release request-local end release”,则单方终止多帧操作模式。不用发DISC帧通知对方。/直接用“Release confirm”向第三层报告。/该方式主要用于移动台从SDCCH被指配到FACCH，对SDCCH上原有多帧操作模式的终止。46LAPDm协议协议（ Um
74、Um接口接口第二层）第二层）/多帧操作模式下信息的传送/I帧发送/收到第三层的原语“DATA REQUEST”后，将该原语带的第三层消息以I帧发送。/只有V(S)V(A)+1才可以进行I帧发送，否则该I帧应存入I帧队列。也就是说，只有在上一个I帧得到确认的条件下才允许发送随后的I帧。/发送I帧时，N(S)=V(S)，N(R)=V(R)，V(S)=V(S)+1/启动T200定时器。/I帧接收/若收到对方的I帧，检查该帧的N(R)是否等于V(R)，若等于，则该I帧为有效帧，否则，应回REJ帧，REJ帧中的N(R)=V(R),即要求对方重发发送序号为V(R)的I帧。只有有效帧才进行下一步处理。/若V
75、(A)=N(R)=V(S),该I帧有效，V(A)=V(A)+1，否则应视为链路故障，用“ERROR_INDICATION“上报第三层，第三层应要求对该链路进行本地释放。/V(R)=V(R)+1。停止T200定时器。/若I帧队列中有I帧，则按照上面的方式发送I帧；否则发送RR，RR中的N(R)=V(R)。以此给确认该I帧。47LAPDm协议协议（ UmUm接口接口第二层）第二层）/多帧操作模式下信息的传送/RR帧接收/若V(A)=N(R)=V(S),该RR帧有效，V(A)=V(A)+1，否则应视为链路故障，用“ERROR_INDICATION“上报第三层，第三层应要求对该链路进行本地释放。/停止
76、T200定时器。/若I帧队列中有I帧，则按照上面的方式发送I帧；若RR帧为Command帧,则发送RR，RR中的N(R)=V(R)。/REJ帧接收/若V(A)=N(R)=V(S),该REJ帧有效，V(A)=V(A)+1，否则应视为链路故障，用“ERROR_INDICATION“上报第三层，第三层应要求对该链路进行本地释放。/停止T200定时器。/按照I帧发送规则重发发送序号等于N(R)的I帧。48LAPDm协议协议（ UmUm接口接口第二层）第二层）/多帧操作模式下信息的传送/T200超时/按照I帧发送规则重发I帧/若重发次数达到N200次，应用“ERROR INDICATION”向第三层报告
77、。第三层应要求对该链路进行本地释放。/L3消息的拆分和拼装/若L3消息的长度大于N201，即一条I帧无法承载整条消息，应将L3消息拆分成多个I帧，并对M比特进行相应设置。/接收端根据M比特将多个I帧拼装成一条完整的L3消息。49LAPDm协议协议（ UmUm接口接口第二层）第二层）/多帧模式的暂停和恢复 在指配新信道时，或切换时，移动台需要在老信道上暂停多帧模式，本地释放，待在指定的新信道上建立好多帧模式后（正常建链），在新信道上予以恢复。如果在新信道上建链失败，应回老信道上重新正常建链后，再予以恢复。网络在发指配或切换命令后，暂停在老信道上的I帧传送，开启定时器T3107或T3103，当在新
78、信道上收到移动台的指配完成或切换完成，则本地释放老信道，在新信道上恢复多帧模式，并停止定时器；当在老信道上收到指配失败或切换失败，则本地释放新信道，在老信道上恢复多帧模式，并停止定时器；当定时器超时，则新、老信道均本地释放。当多帧模式暂停时，未被确认的L3消息应在多帧模式恢复后重新发送。50LAPDm协议协议（ UmUm接口接口第二层）第二层）/DM/ 如果收到SABM但本方由于某种原因无法进入多帧模式，则发送DM/ 如果在空闲模式下收到I帧、监视帧或DISC帧，应发送DM/ 收到DM的一方应通知高层，并进入空闲模式，51LAPDm协议协议（ UmUm接口接口第二层）第二层）/参数定义 N20
79、0的定义：N201的定义：T200的定义：应满足以下公式。系统响应时间：应满足以下公式第二层链路连接和释放:5SACCH:5SDCCH23FACCH/F34FNcomm1 + Trmin = FNcomm2 = FNcomm1 + TrmaxFNresp = FNcomm + Tresp +1for frames of format A and B:for the SACCH: N201 = 18;for the FACCH and SDCCH: N201 = 20.for frames of format Bbis:for BCCH, AGCH, NCH and PCH: N201 = 23.for frames of format Bter:for the SACCH: N201 = 21;for the FACCH and SDCCH: N201 = 23.52
