RACH procedure msg1-msg4 failure in 5G

5G NR
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1

Hi All,
sgNB failure or Scg failure post RRC Reconfiguration complete massage.
Rhe query is: Is it a RACH procedure msg1-msg4 failure in 5G?

Second query is: if failure reason is random access problem what could be the possible reason other than poor radio condition as RSRP is -95 dBm?

2

For random access problem other reason is msg3 retx occur due to crc nok once it reach max limit UE will send SCG failure information due to random access problem.

3

Thanks @ankgitm.
There are 2 different reason for scg failure rlc-MaxNumRetx, & randomAccessProblem.
As you said correctly for max limit reached; what are the reason for random access problem why there is problem in rach with good radio condition.
Is it like msg1 preamble is not heard by NB?

4

Hi @meo, for msg1 issue if rsrp good still gnb not able to listen please check pathloss.
I find sometime high pathloss lead to this issue as well.

5

can you please elaborate further, any counters/kpis to check pathloss and what’s the recommended value to not exceed