What are the major reason for RRC drops in LTE?
RRC drops can be considered as radio link failure.
Few major reasons for this from UE and eNB perspective are:
- UE detected RLF by T310 expiry, max No of RLC retransmissions, integrity check failure, handover failure (T304 expiry) or non‐handover related random access problem;
- eNB detected radio link failures by PUSCH RLF, CQI RLF, Ack/Nack RLF, RLC failure SRB/DRB also might be due to UE capability Enquiry timeout, RRC timouts(re-configuration, re-establishment,trelocation completion), etc;
- eNB initiated release like TA timer expiry and maximum RLC retransmissions exceeded
However better to consider the E-RAB active at the time of release or not with cause release value.
Hope this will be helpful.