河池 IHO 参数优化方案通过增加小区内切次数降低掉话率方案。目前掉话统计指标计算公式为：CELTCHFP:TFCONGPGSMSUB/CELTCHF: TFMSESTB+CELTCHH:THMSESTB。 而CELTCHF:TFMSESTB和 CELTCHH: THMSESTB在 alex 中解释是 These counters count the number of connections successfully established on the TCH. The MS is regarded to have established a connection on the TCH when an ASSIGNMENTCOMPLETE,HANDOVERPERFORMED or in target BSC, HANDOVER COMPLETE message is sent to the MSC. The counters arealso stepped when an SCCP CONNECTION CONFIRM is received from the MSC.MSCBSCBTSMS1Measurement Report(SACCH)2 Prep_Measurement Result 3 Channel Activation4Channel Activation Ack5Assigment Command(FACCH)7Establish Indication6SABM(FACCH)8UA(FACCH)9Assignment Complete(FACCH)10Receiver Ready(FACCH)11HO Performed12Release Request13Release Confirmation14RF Channel Release15 RF Channel Release Ack小区 内切换信令流程如上图所示，因此适当增加小区内切换次数可能会使掉话率分母增加（小区内切信令流程中有MSC收到 HO Performed ）从而降低掉话率。以下就此进行可行性分析。参数定义：IHO ：小区内切换的开关控制参数，ON或 OFF。SSOFFSETUL：在上行链路上设置信号强度的OFFSET。SSOFFSETDL：在下行链路上设置信号强度的OFFSET。QOFFSETUL：在上行链路上设置质量的OFFSET。QOFFSETDL：在下行链路上设置质量的OFFSET。TMAXIHO：针对切换计数器的计时器。小区内切换间的最大时间间隙。MAXIHO：允许的连续小区内切换的最大次数。TIHO：小区内切换功能是在相同的子小区内的符合要求的不同的时隙或信道之间的切换。试点小区选择：根据近一周差小区数据找出掉话率差但同时掉话次数较少的小区作为此次实验的目标小区。掉话率降平均值为 3%需要cellid上行内切最近 1周项 :TCH 占新增 TCHRxQualUL0ULRQ3 ULRQ4 ULSS-90平均值频次用次数含占用次数百分比百分比百分比切换（按平均值）HD4372217.6729162.70204.9278.59%11.39%8.50%45.52%HJ1562121.004104.4362.2385.14%8.57%6.33%42.31%HF1303321.338829.75366.0879.34%15.89%12.75%65.11%HC314520.674127.0039.6796.16%2.22%1.58%63.34%HC304932.006218.5064.8391.40%3.95%2.20%57.92%HJ152413.676205.5260.0879.04%12.77%8.70%32.01%HF139111.337156.6732.2298.62%0.83%0.55%31.87%HJ181522.674216.6443.9796.63%1.74%1.19%30.51%现网参数设置情况：EXCHIDCELLIHOMAXIHOTMAXIHOTIHOHCB10R12HJ15241ON10610HCB10R12HJ15621ON10610HCB10R12HJ18152ON10610HCB3R12HC30493ON2610HCB3R12HC31452ON3610HCB4R12HD43722ON10610HCBSC6R12HF13033ON2610HCBSC6R12 HF13911 ON3610EXCHIDSSOFFSET SSOFFSETSSOFFSETSSOFFSETQOFFSETU QOFFSETUQOFFSEQOFFSETDCELLULNDLPDLNLPLNTDLPLNULPHCB10R12HJ152411185050HCB10R12HJ156211185050HCB10R12HJ181521185050HCB3R12HC304930000HCB3R12HC314521181212HCB4R12HD437221185050HCBSC6R12HF130330000HCBSC6R12 HF139111181212QOFFSETD QOFFSETDQOFFSETU QOFFSETUSSOFFSETSSOFFSETSSOFFSSSOFFSETEXCHIDETULAFCELLLAFRPLAFRNLAFRPDLAFRNDLAFRPULAFRPLAFRNRNHCB10R12HJ152410000HCB10R12HJ156210000HCB10R12HJ181520000HCB3R12HC304930000HCB3R12HC314520000HCB4R12HD437220000HCBSC6R12HF130330000HCBSC6R12HF139110000参数设置建议：计时器设置为不限制连续切换，即将TMAXIHO设置小于 TINIT 如 TMAXIHO=3；放开上行 15dB 信号强度限制，设置 SSOFFSET=15，则信号强度在 -95dBm 以下时不会发生内切换。使 RxQual3-7 级可发生 IHO，设置 QOFFSET=-20，则信号质量在 3 级时可发生小区内切换。小区内切的条件为：为了确定一个小区内切换在哪个 rxqual 电平值上被允许进行， SSOFFSET被加入这个RXLEV_UL值中，总和用于作为 table1 中的表中的指标。以我们设置参数的例子，这个指标为：31+15=46。在表中将可获得这个指标的对应值为：55。 QOFFSET被加入这个值中：57 -20 = 37。这意味着在包括rxquall必须大于这个总和37 才允许进行小区内切换。参数修改RLIHC:CELL=cell,TMAXIHO=3,SSOFFSETULP=15,SSOFFSETULAFRP=15,SSOFFSETDLP=15,SSOFFSETDLAFRP=15,QOFFSETULN=20,QOFFSETULAFRN=20,QOFFSETDLN=20,QOFFSETDLAFRN=20，TMAXIHO=15， MAXIHO=5， TIHO=10;