“无线网络优化经验研究”系列报告-TCH拥塞率高的分析处理

“无线网络优化经验研究”之《TCH拥塞率高的分析处理》第1页共39页TCH拥塞率高的分析处理目录TCH拥塞率高的分析处理..........................................................................................1第一章：前言：...........................................................................................................2第二章：信令流程.......................................................................................................31）正常TCH分配信令流程..........................................................................32）TCH分配拥塞信令流程（起呼、切换中）...........................................43）TCH分配拥塞信令流程分析说明...........................................................5第三章：TCH拥塞率计算公式..................................................................................71）含切换的TCH拥塞率公式......................................................................72）不含切换的TCH拥塞率公式..................................................................7第四章：可能导致TCH拥塞率高的原因及其解决方法.........................................8一、出现突发性话务量增加而且产生话务量时间相对集中......................81）开启TCH排队功能，适当考虑增加排队时长.............................82）开启TCH流量控制功能...............................................................12二、存在均衡覆盖和话务的可能................................................................121）基站实际覆盖范围过大，收缩基站的实际覆盖.........................122）本小区话务量拥塞而临近基站相对较闲，疏导话务至邻区.....203）TCH与SDCCH的拥塞率不均衡，调整二者资源配置.............294）本基站的另外两个小区相对空闲，调整本基站的硬件配置.....29三、邻区故障或参数设置错误导致手机不能正常切换至其他小区........291）主邻区受到强烈干扰导致手机不能正常解出邻区信息.............302）邻区参数错误导致网络不能识别手机上报的邻区信息.............303）本基站或主邻区的时钟失锁比较严重.........................................31四、基站不能正常分配TCH信道................................................................311）硬件问题导致基站时隙退出服务从而降低小区的可用资源.....312）基站传输闪断增加TCH分配失败次数.......................................323）SLEEPINGCELL现象引起TCH信道拥塞................................32五、手机不能正常占用TCH，导致手机重新申请.....................................321）小区载频硬件问题.........................................................................332）参数设置错误问题.........................................................................333）存在频率干扰问题.........................................................................33六、由于基站异常原因导致用户频繁申请资源........................................34七、基站容量不足且尝试了各种方法均未奏效时考虑加站或扩容........34第五章：处理TCH拥塞率高的思路.......................................................................36第六章：结束语.........................................................................................................39“无线网络优化经验研究”之《TCH拥塞率高的分析处理》第2页共39页第一章：前言：我们在谈到网络拥塞时，常常是指信令信道拥塞以及话务信道拥塞。其中话务信道拥塞也就是我们常说的TCH信道拥塞，发生在用户在申请网络服务信令交互之后，一般进行用户的真正话音要由TCH信道承载，TCH信道的分配也称指配过程。出现TCH信道拥塞是说：在指配过程中，如果网络没有可用的TCH信道来分给手机，则系统计一次TCH分配失败。在本文中，笔者主要从出现TCH信道拥塞可能的原因入手，提出一些解决TCH信道拥塞的方法和思路，以供大家参考。“无线网络优化经验研究”之《TCH拥塞率高的分析处理》第3页共39页第二章：信令流程1）正常TCH分配信令流程MSL1ABISRRSMCRMSMSSMMTP/MSCSDCCHL2SABMestabishindictionT3230L3(intialmsg)CMservicerequeststopT3101T303UAok_acc_proc(SDCCH)ms_access_by_type(1510)initialL3informationCMServicerequestCRconn_req_to_mscSCCPconnclassmark3(ifneeded)CCCREFconn_refusedSDCCHsetupidentityrequest(ifMSCneedmoreMSinformation)identityresponsecallproceeding(MSChavegotenoughinformationtosetuptheconnection)callsetupT310facility(ifMShavesomesupplementaryservices,suchascalldivert)assignmentrequestma_req_from_mscstartMSCtimerforinitiateassignmentmaybeefr_req_from_mscassignment,=30sstartassign_successfulassignmentresourceassignmentchannelassignedalloc_tchphysicalcontextrequesttch_usage….physicalcontextconfirmedbusy_tchchannelactivationchannelactivationack.SDCCHassignmentcommandstartT10ma_cmd_to_msexpireT10releaserequestassignmentfailureclearrequestma_fail_from_msstopT10releaserequestFACCHL2SABMclearrequestUAassignmentcompletedstopT10assignmentsuccessfulstopassign_successfulconnectionrequiredconnectionresponsesuccessassignmentcompletetotal_callstopMSCtimerforma_complete_to_mscassignment(totalcall+intracellHO)BSCBTS“无线网络优化经验研究”之《TCH拥塞率高的分析处理》第4页共39页2）TCH分配拥塞信令流程（起呼、切换中）（1）MOC：MSL1ABISRRSMCRMSMSSMMTP/MSCSDCCHL2SABMestabishindictionT3230L3(intialmsg)CMservicerequeststopT3101T303UAok_acc_proc(SDCCH)ms_access_by_type(1510)initialL3informationCMServicerequestCRconn_req_to_mscSCCPconnclassmark3(ifneeded)CCCREFconn_refusedSDCCHsetupidentityrequest(ifMSCneedmoreMSinformation)identityresponsecallproceeding(MSChavegotenoughinformationtosetuptheconnection)callsetupT310facility(ifMShavesomesupplementaryservices,suchascalldivert)assignmentrequestma_req_from_mscstartMSCtimerforinitiateassignmentmaybeefr_req_from_mscassignment,=30sstartassign_successfulassignmentresourcerequestUDT(resetcircuit)expireMSCtimerwithoutresoucenotavailable(DRnotinoperatinassignmentcomplete'ornoqueueingallowedorqueuefullandallTCHsbusy)alloc_tch_failexpireassign_successfulassignmentfailure'ma_cmd_to_ms_blkdassignmentfailureunsuccessfulassignmentassignmentfailureforcequeuestartT11assignmentqueuedqueuingindicationexpireT11releaserequestclearrequestassignmentchannelclr_req_to_mscassignedstopT11BSCBTS（2）Intra_BSS_HO：“无线网络优化经验研究”之《TCH拥塞率高的分析处理》第5页共39页HandoverBlockedRRSM(s)SSMho_recreceivedCRM(t)internalhorequesthoresourcenotavailabl