What could be reason for rrc connection re-establishment during handover and how to debug this issue in LTE?

Question

Upon detecting Radio Link Failure UE will do RRC Connection re-establishment but to do RRC Connection re-establishment security should be activated in UE, otherwise UE will go Idle mode.So here(After detecting RLF) we are resetting all PHY,MAC,RLC,PDCP Configurations but why we are making security should be there to do RRC Connection re-establishment.

Answer 1

There can be multiple reasons of handover failure and after handover failure, re-establishment procedure is executed.
- If re-establishment is reaching to source eNodeB that means handover procedure is initiated two earlier so resolve this issue change the measurement reporting configuration.
- If re-establishment is reaching to target eNodeB that means handover procedure is triggered too late again change the measurement reporting configuration.

Best way to check on UE logs. Sometimes network may send the configuration which is not compatible with UE this can also be the reason of handover failure.