A UE in RRC_CONNECTED, for which security has been activated, may initiate the procedure in order to continue the RRC connection. The connection re-establishment succeeds only if the concerned cell is prepared i.e. has a valid UE context.
建议先确定以下几点:
是否是切换过程的重建?如果是:
1,RRC重建请求消息是在原小区发送的还是目标小区发送的?
2,如果是原小区上发送的重建请求,可以排查下short mac-i,这个需要PDCP的人去看看,具体的算法过程和计算模型,请参考33401 7.4.3和36331 5.3.7.4
(In order to calculate the token, the source eNB shall use the negotiated EIA-algorithm from the AS Security context from the source eNB with the following inputs: source C-RNTI, source PCI and target Cell-ID as defined by VarShortMAC-Input in TS 36.331 [21], where source PCI and source C-RNTI are associated with the cell the UE last had an active RRC connection with and target cell ID is the identity of the target cell where the RRCConnectionReestablishmentRequest is sent to.
- KEY shall be set to KRRCint of the source cell;
- all BEARER bits shall be set to 1;
- DIRECTION bit shall be set to 1;
- all COUNT bits shall be set to 1.
The token shall be the 16 least significant bits of the output of the used integrity algorithm.
)
3,如果是目标小区上发送的重建,看看测量报告有没有发送成功,如果没发送成功,目标小区就拿不到UE context当然就无法计算出mac-I,那么重建被拒就是正常