If CQI is good (~13.5) and BLER is with normal value (~10%), what else could be the reason for Low DL MCS below 6?
As per my understanding, it could be reason that CQI reported to network has not reached properly.
SNR condition could be low.
No, SINR is good like CQI.
This could be, I will check logs for the c-rnti in eNB.
Please check for the BO reported and the iTBS values. PMI too.
Bo is full. Itbs is dependent of mcs per my understanding.
It might be eBN sends PDSCH with lower MCS due to smaller TBS even CQI and SINR reported high in certain condition.
If UE fail to decode it.
Due to CRC error on UE side.
Not sure, in that way I would expected fluctuation and not constant issue.
Both ibler and rbler are normal?
Yes, both blers are fine. Need to check dtx.
if you see BLER value at UE log file, I think it is BLER calculated by UE based on CRC checking of received TBS.
But BLER measure at enb/gnb is calculated based on ACK/NACK received by enb/gnb.
So, if UE BLer is good, BLER at enb/gnb may be still not good due to uplink feedback problem.
If enb detect DTX, it may schedule UE with default MCS, about 2 or 4.
I suggest you to chek uplink quality, interference…