【正文】 3) 手機(jī)側(cè)如何判斷做什么切換：在此以手機(jī)側(cè)發(fā)起切換為例子，當(dāng) RSSI值波動(dòng)不大，但 FER很大時(shí)，說(shuō)明收到干擾，但此時(shí)離原來(lái)的 CS的距離沒(méi)什么變化，只是這個(gè) TCH信道不能用，則一般執(zhí)行 TCH切換；當(dāng) RSSI值下降，此時(shí)一般來(lái)說(shuō) FER也會(huì)升高，則是說(shuō)明原 CS不能使用需要執(zhí)行 RECALL切換。 常見(jiàn)問(wèn)題 2，一系列的“超時(shí)”影響切換： :1200ms, 4次 001超時(shí)結(jié)束切換 Start conditions :“ Link channel establishment request ”,或是“ Link channel establishment rerequest ” Stop conditions :“ Link channel assignment” 或是“ Link channel assignment reject” 31 57 00 01 02 02 09 00 aa RT CS link cch req 在找到新 CS后 ,向新的 CS做業(yè)務(wù)信道分配請(qǐng)求 30 0f 00 20 08 00 00 00 00 00 00 00 00 3b RT L1 pch information 30 04 00 20 07 01 0a RT L1 primitive 30 0f 00 20 08 00 00 00 00 00 00 00 00 3b RT L1 pch information 30 0f 00 20 08 00 00 00 00 00 00 00 00 3c RT L1 pch information 30 0f 00 20 08 1a 57 18 75 25 85 10 00 3c RT L1 pch information 30 11 00 20 08 ff ff ff ff ff 85 10 00 RT L1 null scch information 30 0f 00 20 08 00 00 00 00 00 00 00 00 3c RT L1 pch information 30 04 00 f2 01 RT L1 primitive 30 35 00 02 aa RT TR001P Timer Out ,001超時(shí) 31 57 00 01 02 02 09 00 aa RT CS link cch req 向該基站重新請(qǐng)求業(yè)務(wù)信道 常見(jiàn)問(wèn)題 :200ms, 4次超時(shí)結(jié)束切換 Start conditions: Without unwanted signal in the TCH designated by “Link channel assignment” Stop conditions: “Synchronization establishment” reception 80 0c 00 14 05 29 40 0a L1 indication uwave to RT 30 04 00 20 02 01 00 RT L1 primitive 30 09 00 03 00 aa RT L1 uwave IND 在獲得業(yè)務(wù)信道以后 ,向該信道發(fā)送同步信息 . 80 0a 00 05 4d 00 02 L1 est tch 30 04 00 f2 02 RT L1 primitive 30 36 00 04 aa RT TR101P Timer Out 200ms后沒(méi)有回復(fù)確認(rèn) 31 60 00 02 02 02 31 00 aa RT CS link cch rereq 重新請(qǐng)求信道 在 log中我們能發(fā)現(xiàn)在建鏈中存在大量的 TR001和 TR101超時(shí) ,這個(gè)是無(wú)法避免的 ,但是他們的存在確實(shí)對(duì)手機(jī)在弱信號(hào)區(qū)的切換有很大的影響 , 常見(jiàn)問(wèn)題 ： , 2d 00 00 00 02 7e 07 l2 rx all ifrm before sending to l3 27 00 00 00 00 04 06 8e 40 21 from L1 data sacch 2d 00 00 00 03 43 01 l2 rx all ifrm before sending to l3 27 00 00 00 00 04 18 0d 24 00 from L1 data sacch 2d 00 00 01 04 04 81 l2 rx all ifrm before sending to l3 2c 00 00 45 01 07 45 08 03 02 85 90 l2 send to msg to l3 26 00 00 00 04 b1 0d l2 to l1 data req (sacch) 35 45 00 45 01 07 45 08 03 02 85 90 CC CS: DISCONNECT CS向手機(jī)發(fā)送斷鏈指示 ,PS不得不掉話 36 95 00 03 02 85 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 CC PM: DISCONNECT 此時(shí)的掉話往往沒(méi)有征兆 ,突然斷線 ,這個(gè)現(xiàn)象不是我們軟件協(xié)議所能控制的 ,在現(xiàn)實(shí) log中此類(lèi)的斷線比例也不是很高 ,所以我們一般不對(duì)這種掉線分析。手機(jī)性能測(cè)試經(jīng)驗(yàn)分享 1,主叫流程 2,通話切換 主叫流程 PS主 CS Link channel establishment request Synchronization burst Synchronization burst SABM CC Call Proceeding RT definition information request RT definition information acknowledge SCCH Link channel assignment SCCH FACCH/SACCH UA FACCH/SACCH CC Setup FACCH/SACCH FACCH/SACCH FACCH/SACCH FACCH/SACCH RT function request FACCH/SACCH RT function request response 鏈路信道建立請(qǐng)求消息 終端鏈路信道指配消息 (信道的頻點(diǎn)和時(shí)隙的位置 ) 同步突發(fā)脈沖 ,在呼叫建立過(guò)程和切換建立時(shí)隙的頻率和時(shí)間同步。 TCH建立失敗而掉話 .(切換流程中 ) 1)同步超時(shí) : 30 41 00 0e f2 0d RT TRMONITP Timer Out 30 4b 00 9e 01 11 ae a6 02 RT CS_ID 30 4b 00 9e 01 11 ae a6 02 39 RT CS_ID 找到一個(gè)合適的基站 31 57 00 01 02 02 09 00 RT CS link cch req 向該 CS做建 TCH請(qǐng)求 80 1c 00 02 03 L1 ready to tx scch 30 04 00 f2 01 RT L1 primitive 30 35 00 0f f2 01 RT TR001P Timer Out ,從而建鏈超時(shí) 31 57 00 01 02 02 09 00 RT CS link cch req 重新請(qǐng)求 80 1c 00 05 03 L1 ready to tx scch 30 0f 00 20 08 00 00 00 00 00 00 00 00 36 RT L1 pch information 80 11