紧急拨号之----T911需求

最新推荐文章于 2025-03-12 17:28:56 发布

原创

最新推荐文章于 2025-03-12 17:28:56 发布 · 516 阅读

0 ·

CC 4.0 BY-SA版权

在E911 CSFB呼叫期间，即使UE移动到不同位置区，也应能成功收发短信。分析发现，当LTE的TAI与WCDMA的LAC不匹配时，UE应执行位置更新（LU）。但实际情况中，由于M*平台未按协议执行LU，导致MM状态为NOT_UPDATED，从而无法建立MM连接发送短信。解决方案涉及修改SBP文件以触发LU。

Issue Description:

During an E911 CSFB Call, UE should successfully send and receive text messages (to PSAP and other users) even if UE moves to a different Location Area during CSFB establishment.

show Log Analysis:

查看log，发现LTE下的TAI与WCDMA下的LAC不一样，也就是说CSFB到WCDMA后，UE应该会执行LU , 查看最新的协议TS23.272 :

When the target RAT for emergency call due to CSFB is selected based on cell re-selection or redirection by the network and the UE moves to a different LA then it is possible that the UE continues the emergency call setup without performing a location updating procedure. In this case, the UE performs the emergency call setup with IMSI NOTE 2:

这里是说手机是可以不进行LU ，但是有个前提是emergency call setup with imsi note2 ,再来看协议，发现这种情况是说的是

说的3G下没有PS业务的情况下才可以不进行LU.

继续看协议:

查看6.2章节说明: