5.49.8 Support of regulatory service via MWAB

Based on the OAM configurations, an MWAB may support emergency services for UEs connected to the MWAB-gNB.

When the MWAB determines that a UE which connects to the MWAB-gNB initiates an emergency PDU Session, e.g. via AS layer signalling, or based on the ARP of the PDU Session context, the following handling applies:

• If the HPLMN of MWAB-UE has configured it with specific S-NSSAI and DNN for BH PDU Session(s) to serve emergency PDU Session for UEs accessing this MWAB, the MWAB uses a BH PDU Session associated with this specific S-NSSAI and DNN. The MWAB-UE establishes such PDU session if it was not yet established.
• If a new BH PDU sessions using this specific S-NSSAI and DNN is established, the emergency PDU Session establishment procedure for the UE(s) served by the MWAB-gNB should not be interrupted by the establishment of the new BH PDU Session. To avoid interruption of the establishment of the emergency PDU Sessions of the UE(s) served by the MWAB-gNB, the MWAB-gNB should complete the emergency PDU Session establishment by using the existing BH PDU Sessions for N3 traffic and then trigger PDU Session resource modification procedure for the emergency PDU Sessions of the UE(s) to associate the emergency PDU Session N3 interface to the new BH PDU Session to serve emergency PDU Session for UEs accessing this MWAB.
• If the HPLMN of MWAB-UE has not configured the MWAB-UE with specific S-NSSAI and DNN for BH PDU Session(s) to serve emergency PDU Session(s) for UEs accessing this MWAB, the MWAB reuses the existing BH PDU Session(s) for N2/N3 interface.
• If there are UEs with emergency services, the MWAB-gNB will not stop operating (e.g. due to de-authorization) as MWAB until it handovers the UEs to other cells as described in clause 5.49.3.
• Based on configuration for the specific S-NSSAI and DNN for BH PDU Session to serve emergency PDU Sessions, the BH PLMN/SNPN and the MWAB attempt to guarantee the resources of the BH PDU session(s) to serve emergency PDU Session in the BH PLMN/SNPN so that they are not released when MWAB is serving the emergency services.

NOTE: If the MWAB is configured to support emergency services for the UEs it serves, it is assumed that the MWAB Broadcasted PLMN/SNPN and BH PLMN/SNPN are in the same country.