GB信令反映无线问题信息.docVIP

RADIO-STATUS信令介绍 Radio-status作为表征无线网络状态的重要标示，根据3GPP TS 48.018 7.3 Radio Status procedure的解释： A BSS and an MS radio interface communication status may change due to the following: The MS goes out of coverage and is lost; This condition is signalled by setting the Radio Cause value to Radio contact lost with MS. The link quality is too bad to continue the communication; This condition is signalled by setting the Radio Cause value to Radio link quality insufficient to continue communication. The BSS has ordered the MS to perform a cell reselection. This condition is signalled by setting the Radio Cause value to Cell reselection ordered. The BSS is preparing to order the MS to perform a cell-reselection to a new cell and internal re-routing of packets to the new cell is not possible. This condition is signalled by setting the Radio Cause value to Cell reselection preparation. The BSS has detected that the packet cell change order has failed. This condition is signalled by setting the Radio Cause value to Cell reselection failure. Conditions 1) and 2) indicate that attempts to communicate between an MS and an SGSN via this cell should be suspended or abandoned. An SGSN shall stop sending LLC-PDUs to the cell for the MS. The criteria for deciding whether condition 1) or 2) has occurred is not in the scope of the present document. 通过Gb平台统计现网中的Radio-status携带的Cause信息均为the MS goes out of coverage and is lost。可见指示的是移动终端所处位置不在覆盖区域内，对于无线环境来说终端当时所处位置存无线环境相对较差的情况。 例： 上例中可见在间隔91s之后才进行RA-capability-update。说明在期间91s内因为无线环境问题导致核心网和手机失去联系。 FLUSH-LL信令介绍 FLUSH-LL过程用于Cell Update后SGSN指示旧小区删除缓存区中的无用数据，由SGSN给旧小区发送一个FLUSH-LL PDU。 Cell Update的信令流程为： 当手机在Ready状态进入一个与原小区处于相同路由区的小区时，就会发起一个Cell Update过程。手机通过在新小区发送一个任意的上行LLC Frame将手机相关信息通知BSC，而BSC则添加BVCI、RAC、LAC等信息后再发送至SGSN。 当SGSN发现小区改变后，便向BSS发送FLUSH-LL PDU来将储存在旧的BVC的该手机所有的LLC-PDU删除或传输到新的BVC。 对应于FLUCH-LL PDU，BSS将会向SGSN发送FLUCH-LL-ACK PDU，其中包括TLLI和原先的那些LLC-PDU是被删除了还是被传输到新的BVC的指示（决定是否需要重发数据）。 数据将在传输至新小区内恢复。 例： FLUCH-LL中携带的信息如下： 可见BVCI(old)指示了旧