【正文】 BACBAUE lost due to S1 I/F down?pmUeCtxtRelAbmonmalEnbActTnfAaiL+ YesHO fails UE dropped? NopmUeCtxtRelAbmonmalEnbActfHO+ YesUE connection lost? NopmUeCtxtRelAbmonmalEnbActfUELost+ Yes NoUE lost due to cell downtime (manual intervention)pmUeCtxtRelAbmonmalEnbActfActCad+ YesRelease due to UE preempltion NopmUeCtxtRelAbmonmalEnbActfActCad+ Yes NoEnd of UE context release、掉線率處理經(jīng)驗(yàn)及流程失敗counter原因查找失敗原因優(yōu)化建議pmUeCtxtRelAbnormalEnbActUeLost查看是否存在弱覆蓋弱覆蓋引起掉話調(diào)整工參或者增加新站加強(qiáng)覆蓋pmUeCtxtRelAbnormalEnbActUeLost查看PUCCH和PUSCH是否存在上行干擾干擾引起的掉話如果UE引起的干擾，可嘗試優(yōu)化P0參數(shù)；如果是外部干擾，需清除干擾源pmUeCtxtRelAbnormalEnbActTnFail檢查告警信息，看是否存在傳輸問題傳輸異常引起掉話解決傳輸問題pmUeCtxtRelAbnormalEnbActCdt查看告警及小區(qū)歷史不可用信息ENB問題查找小區(qū)down的原因，恢復(fù)小區(qū)可用性pmUeCtxtRelAbnormalEnbActHo檢查源小區(qū)的鄰區(qū)里是否存在和目標(biāo)小區(qū)同頻的相同PCI鄰區(qū)HO引起的掉話解決越區(qū)覆蓋問題，并刪除不合理的鄰區(qū)；或者修改其中一條鄰區(qū)的PCIpmUeCtxtRelAbnormalEnbActHo目標(biāo)小區(qū)是否存在上行干擾HO引起的掉話解決干擾問題pmUeCtxtRelAbnormalEnbActHo目標(biāo)小區(qū)是否擁塞，或者license受限HO引起的掉話擴(kuò)容，或者分流pmUeCtxtRelAbnormalEnbActHo目標(biāo)小區(qū)是否弱覆蓋HO引起的掉話調(diào)整工參或者增加新站加強(qiáng)覆蓋、相關(guān)案例、高上行干擾導(dǎo)致高掉線率一、問題描述岳陽岳陽金緣花園3小區(qū)無限掉線率較高，該小區(qū)無接入無切換，異常的eNB請(qǐng)求釋放上下文數(shù)205，初始上下文建立成功次數(shù)0.二、原因分析后臺(tái)登錄該站發(fā)現(xiàn)該站不存在基站故障告警，有強(qiáng)干擾。、駐波告警導(dǎo)致高掉線率一、問題描述室分站點(diǎn)小區(qū)4687901因駐波比超限，導(dǎo)致該站點(diǎn)的接入成功率、無線掉線率較差。主要指標(biāo)如下圖：DateERBS NameEUtranCell Id無線掉線率pmUeCtxtRelAbnormalEnbActHo201514YUYYYXhujiaELR6601774373PT774373137．16%201二、問題分析通過后臺(tái)對(duì)該站點(diǎn)進(jìn)行KPI核查，發(fā)現(xiàn)向10367952切換成功率極低，兩個(gè)小區(qū)覆蓋107國道： DateEUtranCellTDDEUtranCellRelationpmHoExeSuccLteIntraFpmHoExeAttLteIntraF201514774373110367952412133 核核查小區(qū)參數(shù)，發(fā)現(xiàn)目標(biāo)小區(qū)與源小區(qū)同PCI導(dǎo)致切換失?。喝⒔鉀Q措施修改10367952小區(qū)PCI：四、處理結(jié)果處理后指標(biāo)如下：DateERBS NameEUtranCell Id無線掉線率pmUeCtxtRelAbnormalEnbActHo201516YUYYYXhujiaELR6601774373PT77437310．34%1 切換成功率、理論介紹切換成功率是系統(tǒng)移動(dòng)性管理性能的重要指標(biāo)，按照切換頻點(diǎn)維度可分為同頻切換和異頻切換；按照切換方式的維度可分為站內(nèi)切換、X2切換和S1切換。
切換成功率=（eNB間S1切換出成功次數(shù)+ eNB間X2切換出成功次數(shù)+ eNB內(nèi)切換出成功次數(shù)）/（eNB間S1切換出請(qǐng)求次數(shù)+ eNB間X2切換出請(qǐng)求次數(shù)+ eNB內(nèi)切換出請(qǐng)求次數(shù)）*100%
、詳細(xì)counter統(tǒng)計(jì)節(jié)點(diǎn)UE context release is triggered by UE context release requestUE sends “bad coverage”measurement report to RBSpmBadCovEvalReport +pmBestCovEvalReport +Valid redirect target ? NOpmMeasMissingNeighRel + YesHandover is triggered by the UE sending measurement reports Source RBS Handover request Target RBSpmHoPrepAttLteIntraF +pmHoPrepAttLteIntraFQci +Handover oscillation detected? YESpmHoOscIntraF +Lack of license for intra LTE intra freq handover? NoTarget RBS sends handover preparation failure to MME YespmHoPrepRejInLicMob + NoConnected users license exceededTarget RBS sends handover preparation failure to MME YespmHoPrepRejInLicConnUsers +Lack of license for RLC UM? NO Target RBS sends handover preparation failure to MME YespmHoPrepRejInLicRlcUm + NoABBALicense for Multiple ERAB exceeded ?License for Multiple ERAB exceeded ?Target RBS sends handover preparation failure to MME YespmHoPrepRejInLicMultiErab +High load or over load? NoTarget RBS sends handover preparation failure to MME YespmHoPrepRejInHighLoad + or pmHoPrepRejInOverload +All UE’s bearers rejected during bearer admission?License for Multiple ERAB exceeded ? NoTarget RBS sends handover preparation failure to MME YesHandover req ack is received by source RBS from target RBS pmHoPrepRejInBearerAdmissionRej + No Source RBS Handover request Target Acknowledge RBSpmHoPrepSuccLteIntraF + pmHoPrepSuccLteIntraFQci + Source RBS sends RRC connection reconfig to UE UE RRC conncetion Source RBS reconfiguration pmHoExeOutAttQci +UE RRC conncetion traget RBSreconfiguration plete pmHoExeAttLteIntraF +Source RBS SN status transfer traget RBS Target RBS Path switch request MMETarget RBS Path switch request ack MMESource RBS receives UE ctx release mand from target RBS Source RBS UE context release Target RBS mandpmHoExeOutAttQci +pmHoExeOutAttQci +End of intrafrequency X2 handover、切換成功率處理經(jīng)驗(yàn)及流程 失敗階段原因查找失敗原因優(yōu)化建議切換準(zhǔn)備階段失敗目標(biāo)小區(qū)cell down檢查目標(biāo)小區(qū)健康狀態(tài)恢復(fù)目標(biāo)小區(qū)的可用性切換準(zhǔn)備階段失敗目標(biāo)小區(qū)硬件問題檢查目標(biāo)小區(qū)告警，確定目標(biāo)小區(qū)RRU、天線等是否存在問題，或者目標(biāo)小區(qū)是否掛死解決目標(biāo)小區(qū)告警和其他硬件問題切換準(zhǔn)備階段失敗傳輸問題檢查目標(biāo)告警和小區(qū)可用性，確定是否傳輸問題解決傳輸問題切換準(zhǔn)備階段失敗目標(biāo)小區(qū)擁塞檢查目標(biāo)小區(qū)license（connect user，PRB資源）擴(kuò)容受限license，或者修改切換參數(shù)引導(dǎo)源小區(qū)向周邊其他小區(qū)切換切換準(zhǔn)備階段失敗目標(biāo)切換開關(guān)為disable檢查目標(biāo)小區(qū)切換開關(guān)正確配置切換相關(guān)參數(shù)切換準(zhǔn)備階段失敗MME TAC list缺失或不正確檢查MME配置正確在MME上