NeedforGapsInfoNR in R16

3GPP R16 introduced new IE NeedForGaps in RRCReconfigurationComplete & RRCResumeComplete messages. Here, UE need to provide measurement gap information {gap, no-gap} to the network against the target frequency bands sent by gNB.

My question is, how UE is determining which target frequency bands need gaps or no-gaps? Appreciate your help?

Also why gNB need this information from UE? Why gNB cannot determine by itself

The IE NeedForGapsInfoNR indicates whether measurement gap is required for the UE to perform SSB based measurements on an NR target band while NR-DC or NE-DC is not configured.

TS 138 331 V16.4.1

That I know. I want to know, how UE determines whether gap is required or not for each target frequencies indicated by gNB ibn NeedFOrGapsConfigNR IE.

Hi Pawsach

As my experience, UE know which CA combination and ENDC combination which UE can support.
Base on those combination, UE know which inter-frequency UE can measure in connected modem without gap.

For example, : If UE support 3CA 38A_40A_40A . UE can report interFreqNeedForGaps B40 is failed in case UE is working in 2CA 38A_40A (Pcell B38_Scell B40) . I think UE can do that because RF and HW CA mechanism allows UE can do that. Because UE is working in 2CA 38A_40A, UE can active 3CA 38A_40A_40A to measure B40 inter-frequency.