Contention resolution is successful but no RrcSetup

5G NR
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1

Hi Experts.

Anyone has the issue in SA system that contention resolution is successful but no RrcSetup after that and after t300 expiration rrc establishment failed?

If I’m not wrong msg4 contention resolution just means that UE detected UE identity on PDCCH properly but RRcSetup should be on PDSCH.

Could be this some issue with PDSCH decoding? Any idea?

2

Read this:

But: do you see the rrcrequest sent?

3

Yes, RrcSetupRequest is sent.

And after 1sec is failing as no RrcSetup msg.

4

And RF is good?

In logs do you see the DCI for RRC setup?

What kind of tool are you using?
If QXDM you will be able to torubleshoot if not forget it.

This is not something to to with TEMS or other drivetest tool.

5

Not perfect but fair enough (SINR around 5).

6

Yes SINR 5 is good.

I have seen calls surviving even at SINR = -10 dB

Ok, now after MSG 4, do you see the PDCCH for your UE in QXDM? It should be with QPSK and aggregation level 4 maybe 8.

DCI Format 1_1

7

Actually is XCAP but yes, during the next period I see DCI for both DL and UL.

8

Ok, then try going all the UE layers: try at phy layer see if pdsch is there, then go at mac layer see if pdsch is there, then go at rlc layer see if pdsch is there then go at RRC layer and see if pdsch is there.

RRC setup is quite a big message.

So probably you will have to analyse several Sequence numbers.

At each layer.

You have to make sure the DCIs are for your UE scrambled with correct RNTI.

9

Yes, with c-rnti.