We can see these message from the logfile (RRC Reconfig Message) there is any message related with RLF. in the message it will display the RLF parameters indicate number of out of sync indications and the corresponding timer till RLF.
The UE will monitor the Radio quality Condition of the Primary Cell to indicating Out of Sync / In Sync status. UE will measure the SINR obtained from the Node and will report PMI, RI, CQI. and from CQI, Node will mapping the MCS. and from Node, there is BLER which is maintained at a certain percentage. Let say >10% BLER will be said as out of Sync, and >2% will be said as in Sync
n310 : n20
This means that will counting 20 times. after 20 times reported, the t310 will start measure. If n311 In-Sync appear, that will stops t310 timer = No RLF
n311 : n1
This means that will counting for 1 time, if n311 In-Sync not coming and t310 has finish, RFL will be Trigered.
RLF can be triggered due to uplink as well:
1. RLF triggered due to RACH failure ( if UE is unable to send msg1 to ms4). SCG addition failure.
2. if in uplink RLC layer doesnt acknowledge the data from MAC layer and trigger RLF. this is generally triggered after expiry of maxRetxThresh. RLC layer polls MAC layer tPollTimer times for acknowledgement, finally if it doent receive it initiates a RLF.
