TR 23.743 (SA2)
Study on Optimisations
on UE Radio Capability Signalling

With the increase of the size of UE radio capabilities driven by additional bands supported by RAN specifications and UE support of significantly more band combinations, the size of the UE Radio Capabilities has and will significantly grow from Rel-15 onwards, an efficient approach to signal UE Radio Capability information is therefore needed.

This study item shall address two issues:

• Optimizations of system procedures pertaining to the transfer UE Radio Capabilities related information to RAN.
• Optimizations of system procedures related to transfer UE Radio Capabilities impacting the Core Network.

The overall goal is to study mechanisms to reduce the signalling over Uu, CN-RAN, CN-CN and RAN-RAN interfaces as well as the processing load in core and RAN (taking into account how frequently those message transfers and corresponding processing occurs) working in collaboration with RAN WGs for the related RAN interfaces and CT WG4 for the CN interfaces and NFs.

At minimum, the study shall consider the UE Radio Capabilities related aspects and any other optimisation which is deemed necessary in collaboration with RAN WGs. The study also considers scenarios where the UE radio capabilities change based on various events triggered in NAS (e.g. when certain services are not supported in one system/access and the UE wants to stay registered in another system/access, the UE may disable the radio capability for accessing the first system).