Gsm呼叫流程绝对经典（PPT40页)

1、GSM目的和内容目的介绍GSM正常的呼叫流程（空中接口、A-bis接口和A接口）介绍部分常见的异常中断的流程内容GSM网络协议介绍GSM逻辑信道介绍无线链路建立流程（Radio and Link Establishment Procedure）TCH正常分配流程（Normal Assignment Procedure） 主叫流程（Originating Call）被叫流程（Terminating Call）位置更新流程（Location Updating）切换流程（Handover Procedure）呼叫释放流程（Call Release Procedure）信道释放流程（Channel R

2、elease Procedure）GSM协议层数无线网络优化主要关心第三层的信令无线网络优化主要关心DTAP、RSL的信令无线网络优化主要关心DTAP、BSSMAP和部分SCCP的信令DTAPRSLOMLGSM网络协议Layer 3介绍RR : 无线资源管理（Radio Resource Management）由MS、BTS和BSC控制功能举例Paging管理（Paging Management）加密管理（Ciphered Mode Management）频点分配（Frequency Redefinition）信道分配（Dedicated Channel Assignment）切换（Hando

3、ver Management ）测量和功率控制（Measures and Power Control）MM : 移动性管理（Mobility Management）由MS和MSC / VLR控制功能举例鉴权和身份识别（Authentication / Identification Procedures）位置更新（Location Updating）IMSI Attach / DetachGSM网络协议CC : 呼叫控制（Call Control）由MS和MSC控制功能举例呼叫处理和路由（Call processing and routing）双音多频（DTMF Facilities）短消息服务

4、（Short Message Service）附加服务（Supplementary Service）GSM网络协议呼叫流程中常用的逻辑信道PCH寻呼信道（Paging Channel）RACH随机接入信道（Random Access Channel）AGCH接入认可信道（Access Grant Channel）SDCCH独立专用控制信道（Stand-alone Dedicated Control Channel）SACCH慢联系控制信道（Slow Associated Channel）TCH话务信道（Traffic Channel）FACCH快联系控制信道（Fast Associated C

5、ontrol Channel）GSM呼叫流程中常用的逻辑信道PCHRACHAGCHSDCCH + SACCHTCH/FACCH + SACCH定义手机与网络间建立一个无线链路，用于信令传送包括以下四个步骤Paging过程（Paging Procedure）（仅用于被叫流程中）随机接入过程（Random Access Procedure）立即分配过程（Immediate Assignment Procedure）SCCP联接建立过程（SCCP Connection Establishment Procedure） 当手机需要与网络发生联系时，必须要先建立无线链路和A接口的信令连接无线链路建立流程

6、MSBTSBSCMSCChannel RequestChannel RequiredChannel Activation（SD）Channel Act Ack （SD）Immediate AssignmentCommandUI Imm Assignment / Imm Ass ExtST9103ET9103ST3126ET3126ST3101SABM L3 InfoEst Ind L3 InfoSCCP Con Rqrd L3SCCP Conn ConfirmET3101ST9105ET9105UA L3 Info（RACH）（Est Cause，Rnd Nbr）（Est Cause，Rnd

7、Nbr，TA）RACH_TA_Filtering（TA，BS/MS_TxPwr -Max，Chann）Timer；S - Start；E - EndEntity信令消息空中接口Abis接口A接口（Rnd Nbr，TDMA Frame Nbr，Chan ，TA）（AGCH）同时对两个MS分配SDCCH（SDCCH）BSC开始对MS发出的上行DTAP消息排队（如CM Serv Abort消息）。如果收到MS发出的Classmark Change消息，BSC会在SCCP连接完成后发Classmark Update消息给交换机如CM Serv Req，Pag Res，Loc Update Req等Se

8、t Asynchronous Balance Mode。在任何新信道登陆时均会有SABM过程Unnumbered Ack无线链路建立流程无线链路建立流程异常情况对不同的呼叫类型有不同的等待时间：WI_EC/CR/OC/OP.(OP主要指LU,被叫没有相应等待时间)SDCCH拥塞如果BSC在收到Channel Required时，相应小区没有空闲的SDCCH，BSC将会如果小区参数En_Imm_Ass_Rej=“True”，则发Immediately Assignment Reject否则忽略Channel Required消息T9103超时BSC发RF Channel Release消息到BT

9、SBSC收到Channel Activation NAck消息BSC内部释放BTS的相应无线信道 (没有任何消息在Abis接口上传送) T3101超时Layer 3无法建立 BSC发RF Channel Release到BTST9105超时BSC通过呼叫释放过程（ Call Release Procedure）释放原先建立的SDCCH连接在A接口，BSC向MSC发SCCP释放请求 在RF部分，BSC向手机和BTS发信道释放消息 仅在BSC内部资源表中释放，在Abis上没有信令传送当信道激活不成功时触发的BTS RF Chan Rel不包含Phys Cont Req过程BSC收到Establis

10、h Indication消息，但消息中不含Layer 3 InformationBSC向手机和BTS发信道释放消息Abis上的其它异常中断消息的处理BSC收到Error IndicationCause为 : “T200 Expiry” : 监视SABM和UA过程“Unsolicited DM Response” (发生在Disconnect过程中）“Sequence Error”释放：A接口上，BSC发Clear Request “Radio Interface Failure”到交换机BSC向手机和BTS发信道释放消息BSC收到Connection Failure indication (C

11、ause : Radio Link Failure)在A接口上，BSC发Clear Request “Radio Interface Failure”到交换机BSC向BTS发RF Channel Release消息BSC收到Release Indication当收到手机发出的DISC消息A接口上，BSC发Clear Request “Radio Interface Failure”到交换机BSC向手机和BTS发信道释放消息无线链路建立流程异常情况MSBTSBSCMSCAuthentication ReqCiphering Mode CmdAuthentication ReqAuthentica

12、tion ReqAuthentication RespAuthentication RespAuthentication RespEncryption CommandCiphering Mode CmdCiphering Mode CmpCiphering Mode CmpCiphering Mode CmpTMSI Realloc CmdTMSI Realloc CmdTMSI Realloc CmdTMSI Realloc CmpTMSI Realloc CmpTMSI Realloc CmpAuthenticationCipheringTMSI ReallocST3260ET3260*A

13、uthentication Reject*IdentificationIdentification RequestST3270ET3270Identification RequestIdentification RequestIdentification ResponseIdentification RespIdentification ResponseST3250ET3250（RAND）（SRES）RAND与Ki经过A3算法得到SRES；经过A8算法得到Kc比较SRES（IMSI）选择加密算法（Permitted Alg，Kc）准备解密接收（Alg，Kc）（Alg（A5算法）开始加密发射和解

14、密接收如正确解密接收，则下条消息加密发射已加密的消息（TMSI）VLR从HLR处得到RAND/SRES/Kc鉴权、身份识别、加密、TMSI重新分配过程鉴权过程中的异常情况鉴权失败如果鉴权过程中使用TMSI，网络将启动身份识别过程。如果手机送上来的IMSI与VLR中TMSI所对应的IMSI不一致，则重新进行鉴权如果鉴权过程中已经使用IMSI，则网络发Authentication Reject消息。这个SIM将被认为是无权的T3260超时第一次超时，网络将重发鉴权请求；第二次超时，网络将释放该MM连接身份识别过程中的异常情况T3270超时第一次超时，网络将重发身份识别请求；第二次超时，网络将释放该

15、MM连接TMSI重新分配过程中的异常情况T3250超时第一次超时，网络将重发TMSI重新分配请求；第二次超时，网络将释放该MM连接鉴权、身份识别、加密、TMSI重新分配过程异常情况定义分配TCH的过程特殊情况排队（Queuing）直接重试（Directed Retry）TCH分配过程MSBTSBSCMSCChannel Activation TCHSABM (FACCH)Channel Activation Ack.Assignment CommandAssignment CommandAssignment RequestPhysical Context RequestPhysical Con

16、text ConfirmEstablish IndicationUAAssignment CompleteAssignment CompleteAssignment CmpRF Channel Release (SD)RF Channel Release Ack.STrr1ETrr1ST9108ET9108ST9103ET9103ST3107ET3107（Chn Type，Priority，CIC，DL DTX，Queuing Flag）（TA，MS/BS_TxPwr）（SDCCH）（TA，MS/BS_TxPwr）（MA，TS，HSN，MAIO，MS_TxPwr）占用TCH时，如需传送信令，则

17、通过Stealing Flag将TCH转换成FACCH一般情况下，在RF信道释放前都有Physical Context Req过程TCH分配过程MSBTSBSCMSCSABM (FACCH)Channel ActivationHO CMDAssignment RequestPhysical Con ReqChan. Act. Ack.HO DetectionUAPhys. InfoAssignment CmpST11ST3103Queuing IndicationET11At this time, a TCH become freeTCH拥塞和排队Assignment RequestST11Q

18、ueuing IndicationET11A Handover alarm is raised. A target BTS is selectedHO CMDHO AccessST9103ET9103TTSTTEstablish IndicationTTHO CMPTHO CMPST3124ET3124ET3103直接重试如果Queuing Ind=True或Queuing_Anyway=True。（当Queuing _Anyway时T11_Forced取代T11TCH分配过程排队和直接重试TCH拥塞情况不允许排队或队列已满在A接口BSC发Assignment Failure No Radio

19、 Resource Available呼叫进入队列，但T11时间内没有TCH空出在A接口BSC发Clear Request No Radio Resource Available呼叫被优先级更高的呼叫挤出队列在A接口BSC发Assignment Failure No Radio Resource Available”T9108超时 : BTS对physical context request没有响应之后的Channel Activation消息中将不带TA和手机及BTS的发射功率信息T9103超时 : Channel Activation没有回应A接口上BSC发Assignment Failu

20、re Radio Interface FailureBSC向BTS发RF Channel Release消息TCH分配过程异常情况BSC收到Channel Activation Negative Acknowledge消息Channel Activation Negative Acknowledge有以下几种原因 :Channel Already Activated (CAA): BSC向手机和BTS发信道释放消息Radio Resource Not Available (RRNA) - Protocol error (PE) : BSC内部释放Requested transcoding ra

21、te not supported (RTRNS) : BSC内部释放Encryption algorithm not implemented (EANI) : BSC内部释放O&M Intervention (OI) : BSC内部释放在A接口上发Assignment Failure消息对于收到Chnav Neg Ack原因为EANI的情况，Assignment Failure的cause为Ciphering Algorithm not supported其它情况， Assignment Failure的cause为Radio Interface FailureTCH分配过程异常情况在原来的信

22、道上（如SDCCH信道）收到Assignment Failure消息 手机收到Assignment Command后，在新信道上发SABM消息，BTS收到后向手机发UA消息。但可能由于空中接口原因，手机没有收到UA消息。手机尝试N200次均未成功。手机将会回到原来的信道。并发Assignment Failure消息BSC收到该消息后在A接口发Assignment Failure Reversion to Old ChannelBSC向BTS发RF Channel Release消息，释放新信道Assignment Command的内容有误手机发现Assignment Command消息中内容有

23、误，手机发Assignment Failure消息到BSCBSC收到该消息后在A接口发Assignment Failure Reversion to Old ChannelBSC向BTS发RF Channel Release消息，释放新信道T3107超时BSC在A接口发Assignment Failure “Radio Interface Message Failure”，并开始T9110计时BSC向BTS发RF Channel Release消息，释放新老信道MSC向BSC发Clear Command消息（呼叫释放），并停止T9110一般情况下，交换机收到该消息后发DISC（temp fai

24、l）TCH分配过程异常情况直接重试中的异常情况没有Candidate cellBSC在A接口发Assignment Failure “No Radio Resource Available”Channel Activation过程中T9103超时 BSC在A接口发Assignment Failure “Radio Interface Failure”BSC向BTS发RF Channel Release消息BSC收到Channel Activation Negative Acknowledge消息Channel Activation Negative Acknowledge有以下几种原因 :Ch

25、annel Already Activated (CAA): BSC向手机和BTS发信道释放消息Radio Resource Not Available (RRNA) - Protocol error (PE) : BSC内部释放Requested transcoding rate not supported (RTRNS) : BSC内部释放Encryption algorithm not implemented (EANI) : BSC内部释放O&M Intervention (OI) : BSC内部释放在A接口上发Assignment Failure消息对于收到Chnav Neg Ack

26、原因为EANI的情况，Assignment Failure的cause为Ciphering Algorithm not supported其它情况， Assignment Failure的cause为Radio Interface FailureTCH分配过程异常情况T3103超时 : 没有收到HO Failure或HO Complete消息BSC在A接口发Assignment Failure “Radio Interface message Failure”BSC向手机和BTS发信道释放消息，释放新老信道收到手机发来的HO Failure消息BSC在A接口发Assignment Failur

27、e “Reversion to Old Channel”消息BSC向BTS发RF Channel Release消息，释放新信道Abis上的其它异常中断消息的处理BSC收到Connection Failure Indicaiton消息Cause为 : “Radio Interface Failure” : 无线链路超时引起的释放释放：A接口上，BSC发Clear Request “Radio Interface Failure”到交换机BSC向BTS发RF Channel Release消息BSC收到Error Report消息BSC收到Error Indication消息BSC收到Relea

28、se Indication消息A中继信道拥塞或不可用情况TCH分配过程异常情况主叫过程（非OACSU情况）MSBTSBSCMSCCall ProceedingESTIN (CM_Serv_Req)RR Connection EstablishmentRR Connection EstablishmentRR Connection EstablishmentAuthentication ProcedureAuthentication ProcedureAuthentication ProcedureCiphering ProcedureCiphering ProcedureCiphering P

29、rocedureTMSI Realloc ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureSETUPSETUPSETUPCall ProceedingCall ProceedingAssignment ProcedureAssignment ProcedureAssignment ProcedureAlertingAlertingAlertingConnectConnectConnectConnect Ack.Connect Ack.Connect Ack.SpeechCM_Serv_ReqOff Air Call Setup（call

30、ed party nbr）先建立TCH，再接通B侧信道。Alerting在TCH上发送（CM Serv Type，Mobile ID，Classmark2，Priority，）SDCCHTCHMSBTSBSCMSCCall ProceedingESTIN (CM_Serv_Req)RR Connection EstablishmentRR Connection EstablishmentRR Connection EstablishmentAuthentication ProcedureAuthentication ProcedureAuthentication ProcedureCipher

31、ing ProcedureCiphering ProcedureCiphering ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureSETUPSETUPSETUPCall ProceedingCall ProceedingAssignment ProcedureAssignment ProcedureAssignment ProcedureAlertingAlertingAlertingConnectConnectConnectConnect Ack.Connect Ack.Connect A

32、ck.SpeechCM_Serv_ReqSDCCHTCH先接通B侧信道，再建立TCH 。Alerting在SDCCH上发送主叫过程（OACSU情况）MSBTSBSCMSCCall ConfirmedESTIN (Paging Resp)RR Connection EstablishmentRR Connection EstablishmentRR Connection EstablishmentAuthentication ProcedureAuthentication ProcedureAuthentication ProcedureCiphering ProcedureCiphering

33、ProcedureCiphering ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureSETUPSETUPSETUPCall ConfirmedCall ConfirmedAssignment ProcedureAssignment ProcedureAssignment ProcedureAlertingAlertingAlertingConnectConnectConnectConnect Ack.Connect Ack.Connect Ack.SpeechPaging ResponseP

34、agingPaging CommandPaging RequestST3113ET3113Paging Group的个数（N）：由BS_AG_BLKS_RES和BS_PA_MFRMS决定;MS的Paging Group = (IMSI mod 1000) mod N;MS只监听自己对应的Paging Group的Paging Req消息（MS ID（TMSI/IMSI），Cell ID（LAC/LAC+CI）（MS ID（TMSI/IMSI），Paging Group）（MS ID（TMSI/IMSI）（最多可同时发4个TMSI）（Mobile ID，Classmark2，Priority，）

35、（calling party nbr）被叫过程T3113超时如果T3113超时，Paging Response消息没有收到，网络会重发Paging消息，并重新开始T3113计时。重试的次数在交换机中定义。Paging失败MSBTSBSCMSCClear CMDESTIN (Loc Up Req)RR Connection EstablishmentRR Connection EstablishmentRR Connection EstablishmentAuthentication ProcedureAuthentication ProcedureAuthentication Procedur

36、eCiphering ProcedureCiphering ProcedureCiphering ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureTMSI Realloc ProcedureLoc Up AcceptChannel ReleaseDeactivate SACCHDISCRelease IndicationUARF Ch ReleaseLoc Up ReqLoc Up AcceptLoc Up AcceptChannel ReleaseRF Ch Release AckClear CMPST3210ET3210（LU Ty

37、pe，MS ID，LAI，Classmark1，）位置更新过程切换分为小区内切换（IntraCell Internal Handover） : 切换原因 (按优先级排序)Cause 15 & 16 干扰切换(High level interference on UL or DL).Cause 10 & 11 : 同心圆内圆电平过低而向外园切换（Too low level, inner zone (inner to outer zone HO, concentric cell) (UL & DL)）Cause 13 : 同心圆外圆电平较高时向内圆切换（Too high level on the

38、UL and DL, outer zone (outer to inner zone HO, concentric cell)）BSC内部小区间切换（Intercell Internal Handover）切换原因 (按优先级排序)Cause 7 : 微小区BadSACCH切换（Several consecutive Bad SACCH frames received (rescue microcell HO)）Cause 17 & 18 : 微小区高门限切换（Too low level in a microcell compared to a high threshold (UL & DL)

39、）Cause 2 & 4 : 质量切换（Too Low Quality (UL & DL)）Cause 3 & 5 : 电平切换（Too Low Level (UL & DL)）Cause 6 : 太长距离且换（Too long MS-BS distance）Cause 22: 扩站小区外小区太短距离切换（Too short MS-BS distance）Cause20: 强制直接重试（Forced Direct Retry）Cause25: GPRS重定向（GPRS Redirection ）切换过程Cause 21: Preferred Band切换（High level in neigh

40、bor cell in the preferred band）Cause 14: 宏小区到微小区切换（High level in a neighbor microcell for macrocell to microcell HO.）Cause 12: PBGT切换（Power Budget (Better Cell HO)）Cause 23: 话务切换（Traffic HO）Cause 24: 综合捕捉切换（General Capture HO）同步切换Intra Cell切换部分Internal Inter Cell切换异步切换切换过程MSBTSBSCMSCMeasurement RepM

41、easurement ResIntra cell切换Phys Context ReqOCOCPhys Context ConfOC : Old ChannelNC : New ChannelNCNCChannel Activation AckChannel Activation Assignment CommandAssignment CommandOCSABMEstablish IndicationUAOCNCNCNCAssignment CompleteNCAssignment CompleteHandover PerformedRF Channel RelOCRF Channel Rel

42、 Ack.OCST9108ET9108ST9103ET9103ST3107ET3107ST_RCR_ACKET_RCR_ACK原信道上的TA、MS/BS_TxPwr被沿用到了新的信道上IntraCell HO总是用Assignment的过程来完成（HO Cause，Cell ID，Chn Type）Intra Cell切换过程TCH拥塞Intra Cell切换将不会发生T9108超时 : BTS对physical context request没有响应之后的Channel Activation消息中将不带TA和手机及BTS的发射功率信息T9103超时 : Channel Activation没

43、有回应Intra Cell切换过程将终止A接口上不会有任何消息传送BSC向BTS发RF Channel Release消息，释放新信道BSC收到Channel Activation Negative Acknowledge消息Intra Cell切换过程将终止Channel Activation Negative Acknowledge有以下几种原因 :Channel Already Activated (CAA): BSC向手机和BTS发信道释放消息Radio Resource Not Available (RRNA) - Protocol error (PE) : BSC内部释放Reque

44、sted transcoding rate not supported (RTRNS) : BSC内部释放Encryption algorithm not implemented (EANI) : BSC内部释放O&M Intervention (OI) : BSC内部释放A接口上不会有任何消息传送Intra Cell切换过程异常情况在原来的信道上（如SDCCH信道）收到Assignment Failure消息 Intra Cell切换过程将终止A接口上不会有任何消息传送BSC向BTS发RF Channel Release消息，释放新信道Assignment Command的内容有误，手机发A

45、ssignment Failure消息到BSCIntra Cell切换过程将终止A接口上不会有任何消息传送BSC向BTS发RF Channel Release消息，释放新信道T3107超时BSC在A接口发Clear Request “Radio Interface Message Failure”BSC向BTS发RF Channel Release消息，释放新老信道形成切换掉话其它异常中断消息Error ReportConnection Failure IndicationRelease IndicationError IndicationIntra Cell切换过程异常情况MSBTSserv

46、ingBSCMSCBTStargetMeas ReportMeas ResultHO Alarm & Candidate CellPhys Context ReqPhys Context ConfChannel ActivationChannel Act Ack.HO CommandHO CommandHO AccessHO DetectionSABMEstablish IndUAHandover CompleteHandover CompleteHandover PerformedRF Channel ReleaseRF Channel Rel. Ack.ST9108ET9108ST9103

47、ET9103ST3103ST3103ST3106ET3106ST_RCR_ACKET_RCR_ACKST200ET200原信道上的TA、被沿用到了新的信道上，而MS/BS_TxPwr将用最大功率在新的信道上发射（AB，DCH）（Cell，MA，MAIO，HSN，TS，TA）（TA被采用）Internal Inter Cell切换过程同步切换MSBTSservingBSCMSCBTStargetHO Alarm & Candidate CellChannel ActivationChannel Act Ack.HO CommandHO CommandHO AccessHO DetectionSA

48、BMEstablish IndUAHandover CompleteHandover CompleteHandover PerformedRF Channel ReleaseRF Channel Rel. Ack.ST9103ET9103ST3103ST3103ST3105ET3105Physical InfoST3124ET3124ST200ET200ST_RCR_ACKET_RCR_ACKPhys Context ReqPhys Context ConfST9108ET9108Meas ReportMeas Result没有Physical Cont Req过程，原信道上的TA不能被沿用到

49、新的信道上测量TA（TA）（TA被采用）在RF信道释放前，有Physical Context Req过程Internal Inter Cell切换过程异步切换TCH拥塞Internal Inter Cell切换将不会发生T9108超时（同步切换）同Intra Cell情况T9103超时同Intra Cell情况BSC收到Channel Activation Negative Acknowledge消息同Intra Cell情况Internal Inter Cell切换过程异常情况在原来的信道上（如SDCCH信道）收到HO Failure消息 Internal Inter Cell切换过程将终止

50、A接口上不会有任何消息传送BSC向BTS发RF Channel Release消息，释放新信道HO Command的内容有误，手机发HO Failure消息到BSCInternal Inter Cell切换过程将终止A接口上不会有任何消息传送BSC向BTS发RF Channel Release消息，释放新信道T3103超时BSC在A接口发Clear Request “Radio Interface Message Failure”BSC向BTS发RF Channel Release消息，释放新老信道形成切换掉话其它异常中断消息Error ReportConnection Failure IndicationRelease IndicationError IndicationInternal Inter Cell切换过程异常情况MSBTSservingBSCservingMSCBTStargetMeas ReportMeas ResultHO Alarm & Candidate CellChannel Ac