UE restrictDCNR - use of dual connectivity with NR is restricted

I think it’s a simulator.

Yes, it is.

Now, so there are 2 issues:

  1. eNodeB shouldnt have setup measurement config for that UE
  2. Even if UE receives meas config from network it shouldnt have sent meas report.

I think “2” will happen because UE always does what eNodeB instruct him to measure.

It’s a simulator, mostly enodeB won’t care about it.

Great.

Did you get what they mean by restricted to upper layers ?

It means upper layers (NAS) in UE & eNodeB are restricted to use 5G NR.

As a general comment, the MME should inform the UE and eNodeB of the restriction. In a normal scenario, the eNodeB would not setup B1 nor add the PSCELL.

That being said, I’ve seen logs where the UE receives the restriction on attach, but the eNodeB setup the B1 and later the PSCELL. The UE goes through and accepts the setup. We didn’t have traces on the NW side to identify where effectively was the issue.

My take on this is: the internal algorithms of the UE are not designed to deal with this duality since it is clearly a issue on the NW side (CN and/or eNB). The spec doesn’t say what to do in these scenarios, therefore, issue should be fixed on the NW side.

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I believe UE will not display “5G icon” when the network sends DCNR restricted.
LTE anchor should not ask UE to measure B1 if it recieves NR restricted from MME

Hello expert,

What’s your final take up with IE restriction on the use of dual connectivity with NR set as restricted ?

In this scenario will UE measure or not 5GNR cell by b1 or b2?

Ideally, restricting DCNR doesn’t mean UE would stop measuring B1 & B2, if it supports SA.
Not sure otherwise.

I’m seeing for NSA measurement there with restriction true.

Then device might be SA capable, as B1/B2 can be for those.

B1, B2 I’m refering for 5G cell.

Yes, for example, if a UE is in 4G and DCNR is restricted by NW, yet if NR measurements are configured, SA UE will measure NR B1/B2 for 4G5 HO.

Ok, got it :+1:
Without UE capability enquiry having NR ask for SA I’m not sure UE SA or not.
I’m seeing only eutra and eutranr ask in ue capability enquiry
But still UE measure 5G NR with restriction true.
Sa-NR-r15 supported indicates UE is SA or not.

When dcnr-restricted=true then eNodeB should not configure UE with b1 measurements for NR.
So your problem is the eNodeB, not the UE.

Now mixed as per @RFSpecialist and @RMatolia it can be possible if UE is SA.
Seems logical to me.

How can we identify DCNR restriction from Ue Log?

Check attach accept.
It’s is there only if dcnr-restricted=true otherwise it is missing.

More details here:

It’s a blog of a friend, expert in IMS 4G and 5G core.

But UE can do HO to SA Freq only it shouldn’t measure NSA Freq.
At gNodeB we have option to indicate cell as NSA or SA.