【正文】 tering（ 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）同時對兩個 MS分配SDCCH（ SDCCH）BSC開始對 MS發(fā)出的上行 DTAP消息排隊（如 CM Serv Abort消息）。手機嘗試 N200次均未成功。Paging失敗MS BTS BSC MSCClear CMDESTIN (Loc Up Req)RR Connection Establishment RR Connection Establishment RR Connection EstablishmentAuthentication Procedure Authentication Procedure Authentication ProcedureCiphering Procedure Ciphering ProcedureCiphering ProcedureTMSI Realloc Procedure TMSI Realloc Procedure TMSI Realloc ProcedureLoc Up AcceptChannel ReleaseDeactivate SACCHDISCRelease IndicationUARF Ch ReleaseLoc Up ReqLoc Up AcceptLoc Up AcceptChannel ReleaseRF Ch Release AckClear CMPST3210ET3210（ LU Type， MS ID， LAI， Classmark1，）位置更新過程t 切換分為p 小區(qū)內(nèi)切換（ IntraCell Internal Handover） : 切換原因 (按優(yōu)先級排序 )– Cause 15 16 干擾切換 (High level interference on UL or DL).– Cause 10 11 : 同心圓內(nèi)圓電平過低而向外園切換（ Too low level, inner zone (inner to outer zone HO, concentric cell) (UL DL)）– Cause 13 : 同心圓外圓電平較高時向內(nèi)圓切換（ Too high level on the UL and DL, outer zone (outer to inner zone HO, concentric cell)）p BSC內(nèi)部小區(qū)間切換（ Intercell Internal Handover） 切換原因 (按優(yōu)先級排序 )– Cause 7 : 微小區(qū) BadSACCH切換（ Several consecutive Bad SACCH frames received (rescue microcell HO)）– Cause 17 18 : 微小區(qū)高門限切換（ Too low level in a microcell pared to a high threshold (UL DL)）– Cause 2 4 : 質(zhì)量切換（ Too Low Quality (UL DL)）– Cause 3 5 : 電平切換（ Too Low Level (UL DL)）– Cause 6 : 太長距離且換（ Too long MSBS distance）– Cause 22: 擴站小區(qū)外小區(qū)太短距離切換（ Too short MSBS distance）– Cause20: 強制直接重試（ Forced Direct Retry）– Cause25: GPRS重定向（ GPRS Redirection ）切換過程– Cause 21: Preferred Band切換（ High level in neighbor cell in the preferred band）– Cause 14: 宏小區(qū)到微小區(qū)切換（ High level in a neighbor microcell for macrocell to microcell HO.）– Cause 12: PBGT切換（ Power Budget (Better Cell HO)）– Cause 23: 話務切換（ Traffic HO）– Cause 24: 綜合捕捉切換（ General Capture HO）p 同步切換 Intra Cell切換 部分 Internal Inter Cell切換p 異步切換切換過程MS BTS BSC MSCMeasurement Rep Measurement ResIntra cell切換Phys Context ReqOCOC Phys Context ConfOC : Old ChannelNC : New ChannelNCNC Channel Activation AckChannel Activation Assignment CommandAssignment CommandOCSABMEstablish IndicationUAOCNCNCNCAssignment Complete NCAssignment CompleteHandover PerformedRF Channel RelOCRF Channel Rel ST9108ET9108ST9103ET9103ST3107ET3107ST_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總是用Assignment的過程來完成（ HO Cause， Cell ID， Chn Type）Intra Cell切換過程t TCH擁塞p Intra Cell切換將不會發(fā)生t T9108超時 : BTS對 physical context request沒有響應p 之后的 Channel Activation消息中將不帶 TA和手機及 BTS的發(fā)射功率信息t T9103超時 : Channel Activation沒有回應p Intra Cell切換過程將終止p A接口上不會有任何消息傳送p BSC向 BTS發(fā) RF Channel Release消息，釋放新信道t BSC收到 Channel Activation Negative Acknowledge消息p Intra Cell切換過程將終止p Channel Activation Negative Acknowledge有以下幾種原因 : Channel Already Activated (CAA): BSC向手機和 BTS發(fā)信道釋放消息 Radio Resource Not Available (RRNA) Protocol error (PE) : BSC內(nèi)部釋放 Requested transcoding rate not supported (RTRNS) : BSC內(nèi)部釋放 Encryption algorithm not implemented (EANI) : BSC內(nèi)部釋放 OM Intervention (OI) : BSC內(nèi)部釋放p A接口上不會有任何消息傳送Intra Cell切換過程 —— 異常情況t 在原來的信道上（如 SDCCH信道）收到 Assignment Failure消息 p Intra Cell切換過程將終止p A接口上不會有任何消息傳送p BSC向 BTS發(fā) RF Channel Release消息，釋放新信道t Assignment Command的內(nèi)容有誤，手機發(fā) Assignment Failure消息到 BSCp Intra Cell切換過程將終止p A接口上不會有任何消息傳送p BSC向 BTS發(fā) RF Channel Release消息，釋放新信道t T3107超時p BSC在 A接口發(fā) Clear Request “Radio Interface Message Failure”p BSC向 BTS發(fā) RF Channel Release消息，釋放新老信道p 形成切換掉話t 其它異常中斷消息p Error Reportp Connection Failure Indicationp Release Indicationp Error IndicationIntra Cell切換過程 —— 異常情況MS BTSserving BSC MSCBTStargetMeas Report Meas ResultHO Alarm Candidate Cell