Failure of ENDC setup - no B1 measurement report send by UE

Hi All.

I have a UE side scenario of failure of ENDC setup (measurement based), there is no B1 measurement report send by UE.

Analysed following initial conditions for ENDC setup:

  • I have verified initial ENDC message exchanges including UE support/NW support (UE capab. exchanges). Also I verified the RRC reconfig for NR measurement object with SSB, periodicity/offset along with SCS spacing details also shared with UE.
  • UE did Ack the RRC reconfig complete.
  • Also UE near cell and is within the threshold range for the nr-rsrp-r15 values.

I have UE end logs only, NW end logs are not available to verify.

Kindly help share your expert views about:

  • What can be the possible root cause?
  • Can there be a possible cause for measurement error from UE end?
  • How to verify this or any other possible root cause?

  • Step1: did you exclude the SIM issue not provisioned for NR? Check in attach accept restrictedDCNR=1

  • Step2: I have see a similar issue with Ericsson RAN, there was an SSB issue, they fixed and then it worked properly but they never mentioned what was the issue.

  • Step3: Do you see in lower layer of the UE logs UE trying to measure NR?

  • Step4: Check settings in yellow:

1 Like

Verified this, Also as cross verification. Commercial REF phone is working with same sim and location. I do not have commercial ref logs

I will try to check Steps 2, 3 and 4 as mentioned.

Thanks for the details and possible scenarios!

There is 1 IE like handover restriction i think in attach accept.

If it’s value 1 then it will impact SCG addition.

Thank you. I will try to verify this too.

In such case is definitely an UE issue.

Are you using a prototype?

It’s a DVT1 model.

I will report the issue.

However, the client might not share the root cause.

I am curious to know if it is possible to catch root cause from my end :thinking:

You should, if you have QXDM.

Then you will see that UE does not attempt to measure NR.

Or it attempts to measure NR but it does not find NR.

Or maybe in ACTIX NR you can see, try there, in message browser.

Do you mean here that on attach accept on LTE there will be parameter restricedDCNR=0 then it can have NR?

SSB issue could be UE only support specific band and where SSB center freq were on different freq band?

Where this message found on SIB2 LTE RACH?

Do you mean restricted DCNR param?

If UE didn’t attempt to measure B1 NR, then is it UE capability for not camping to NR cell?

Check MRDC Capability message.

I just want to add based on my case.

Once you have made sure everything from above which is shared by others is fine then you need to check the UE capability mode to ensure UL/DL are both capable.

Because in my case I found one handset only capable on the DL side so no B1 MR was sent from UE.

  1. Ensure the combination between NR + masters supported by UE if your network is NSA.

Use blind NR add, no B1 event.

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