Section: 5.35A.3.1 UE mobility between a fixed cell and MBSR cell
Content: The procedure of Inter-gNB-DU Mobility as defined in TS 38.401[ NG-RAN; Architecture description ]  [42] or the handover procedure using the Xn/N2 reference points as defined in TS 23.502[ Procedures for the 5G System (5GS) ]  [3] can be used. For UEs in RRC_IDLE and RRC_INACTIVE state when a MBSR goes out-of-service, procedure for cell (re-)selection as specified in TS 38.304[ NR; User Equipment (UE) procedures in Idle mode and in RRC Inactive state ]  [50] for RRC_IDLE and RRC_INACTIVE is used. For UEs in RRC_CONNECTED state, if the MBSR goes out-of-service due to e.g. MBSR moves to an area where the MBSR is not allowed to provide the relay service, the procedure for IAB node release as specified in TS 38.401[ NG-RAN; Architecture description ]  [42] is used. The IAB-donor-CU triggers handover procedure when it is possible for the UEs accessing emergency service and being served by the MBSR, if MBSR is about to become unavailable to provide the services.