3GPP 23.501 v20.2.0 — the document's own text
5.41 NR RedCap and NR eRedCap UEs differentiation
Taught in 26. Relays, satellites, femtos and shared networks (The 5G system architecture, in depth).
This functionality is used by the network to identify traffic to/from UEs accessing over NR RedCap or NR eRedCap, e.g. for charging differentiation.
An NR RedCap UE or NR eRedCap UE using NR shall provide an NR RedCap indication or respectively an NR eRedCap indication to the NG-RAN during RRC Connection Establishment procedure as defined in TS 38.300 [27].
When the UE has provided an NR RedCap indication indicating support of NR RedCap to the NG-RAN during RRC Connection Establishment, the NG-RAN shall provide an NR RedCap Indication to the AMF in the Initial UE Message (see clause 4.2.2.2.1 of TS 23.502 [3] and TS 38.413 [34]).
When the UE has provided an NR eRedCap indication indicating support of NR eRedCap to the NG-RAN during RRC Connection Establishment, the NG-RAN shall provide an NR eRedCap Indication to the AMF in the Initial UE Message (see clause 4.2.2.2.1 of TS 23.502 [3] and TS 38.413 [34]).
When the AMF receives an NR RedCap Indication or NR eRedCap Indication from NG-RAN in an Initial UE Message, the AMF shall store the NR RedCap Indication or NR RedCap Indication in the UE context, consider that the RAT type is NR RedCap or NR eRedCap and signal it accordingly to the SMSF during registration procedure for SMS over NAS, to the SMF during PDU Session Establishment or PDU Session Modification procedure. The PCF can also receive the NR RedCap or NR eRedCap RAT type when applicable from the AMF using the PCRT on Access Type change specified in clause 6.1.2.5 of TS 23.503 [45] during AM Policy Association Establishment or AM Policy Association Modification procedure and from the SMF using the PCRT on Access Type change specified in clause 6.1.3.5 of TS 23.503 [45] during SM Policy Association Establishment or SM Policy Association Modification procedure.
During handover from E-UTRA to NR, the target NG-RAN (i.e. gNB) provides the NR RedCap indication or NR eRedCap indication to AMF in NGAP Path Switch Request message during Xn handover, or NGAP Handover Request Acknowledge message during N2 handover (including intra 5GS N2 handover and EPS to 5GS handover) based on the UE capability information provided by the source RAN to the target RAN as specified in TS 38.300 [27].
The NFs interacting with CHF shall include the NR RedCap or NR eRedCap as RAT type.
Upon AMF change, the source AMF shall provide the "NR RedCap Indication" or "NR eRedCap Indication" to the target AMF.
If a UE supports either NR RedCap or NR eRedCap as specified in TS 38.306 [69] and the UE NG-RAN Radio Capability information changes following the procedure in clause 5.4.4.1, when the UE performs RRC Connection Establishment procedure, the UE shall report the NR RedCap indication or NR eRedCap indication that applies to the new Radio Capability.