TCH分配失敗處理流程定義-TCH分配失敗（含切換）指占用SDCCH后對TCH的呼叫中所有分配TCH信道失敗的總次數。統計的為“切入的HandoverFailure+AssignmentFailure”消息。（溢出包括主叫和被叫占用SDCCH后試圖建立TCH失敗的情況，不包括非常早分配時指派TCH信道用做SDCCH的情況，包括各種切換和直接重試情況。）定義-TCH分配失敗(含切換）(TCH_CALL_REQ-MS_TCH_SUCC_SEIZ_ASSIGN_CMPLT)fromP_NBSC_TRAFFIC+(-MSC_O_SDCCH_TCH-BSC_O_SDCCH_TCH-CELL_SDCCH_TCH+MSC_I_TCH_TCH_AT+MSC_I_SDCCH_TCH_AT-MSC_I_TCH_TCH-MSC_I_SDCCH_TCH+BSC_I_TCH_TCH_AT+BSC_I_SDCCH_TCH_AT-BSC_I_TCH_TCH-BSC_I_SDCCH_TCH+CELL_TCH_TCH_AT+CELL_SDCCH_TCH_AT-CELL_TCH_TCH-CELL_SDCCH_TCH)FromP_NBSC_HO定義-詳細說明TCH_CALL_REQNumberofTCHrequestsfornormalassignment(successful+unccessful)WhentheRadioResourceManagerreceivesaTCHrequestinacallattempt.MSSUCCTCHSEIZUREFORASSIGNMENTCOMPLETENumberoftimeswhenaMSissuccessfullyontheTCHafteranASSIGNMENT_COMPLETEmessage.WhenanASSIGNMENT_COMPLETEmessageisreceivedfromtheMSviaBTStoTCH.TheTCHisreservedandtheMSismovedfromtheSDCCHtotheTCH.Thiscounterisupdatedonlywhenacallisestablishedforthefirsttime,notduringhandovers.ThiscounterisnotupdatedwithsoftwaresFACCHcallsetupbecauseofSDCCHcongestion,directedretryprocedureinBSC,TCHassignmenttosuperreuseTRXinIUOanddirectaccesstosuperre-useTRXinIUO.TCH分配失敗形成的主要原因TCH信道擁塞基站硬件故障（含天饋質量）或硬件故障導致的無線資源有效性下降基站傳輸故障或閃斷內外部干擾致信號質量低弱覆蓋致信號質量低與話務負荷和功率控制等相關參數設置不合理TCH分配失敗處理流程TCH分配失敗主要處理方案覆蓋合理性調整

天線調整或改造TCH容量的增加擁塞嚴重，應擴容或建新站，DCS1800系統使用網絡頻率質量的提升頻率修改或整網頻率規劃，ZERM;弱覆蓋增加新站或天線調整基站硬