FGI bit for B1, B2 event used for NR measurement

Hi Experts,
For NR we are using B1 or B2 event to add SCG, but does UE indicates it support for inter rat NR in UE capability info for event B1 or B2?
Like we have FGI bit 22 indicates we can use B2 event for UTRAN.
FGI bit 41 indicates B1 event support for UTRAN.
Not able to find any FGI bit for B1, B2 event used for NR measurement.

I think it is always B1.
For NR.
Never heard of B2 for NR.

B2 as well I seen in logs.
I configured B2.
In report config.
It’s under specs as well 36.331.
Page 637 3gpp rs 36.331 version 15.9 .0 rel 15
But not able to seen any FGI bit or IE in UE capability info.

I remember B2 event threshold in EUTRAN is to blind HO to WCDMA.
B2 is < B1.
If RSRP of 4G cell < b2 threshold, eNB will request UE to redirect to 3G even if not report any UMTS frequency in B2 event.

B2 I m asking for NR.
B2 looks for serving and target both.
Serving to be worse and target to be better.

Have you found it in 38.331?

Actually we need to look 36.331, as it’s configured at LTE end under RRC connection reconfiguration.
Report config inter rat.

Let me rephrase: What do you want to happen at B2 event in NR?

B1 or B2 both we can use it’s for testing purpose to check UE supporting it or not.

I think FGI bit 15 can be used for B1 NR event but not mentioned in specs explicitly, can you please double check.
You can check 36.331.

I seen in logs they only indicates FGI bit number not description.
But if you see with description as well B1 event for NR, not there.

Here no IE related to B1 or B2 in 5G NSA:


We need to check in Eutra UE capability info.
For B2 I’m able to find it.
Event b2-r15 supported.
You can check in 36.331.
Search for event b2-r15 supported in specs.

There is no UE capability to support the B1-NR measurement.UE supports EN-DC, it should support the B1-NR measurements as well.

Bit 15 in the below PCAP refers to B1 event for UTRAN, GSM and not related to B1-NR event. Refer below details from 36.331 Annex B B.1 Feature group indicators.

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