Section: 6.42.2 Requirements
Content: The 5G system shall support efficient operation of mobile base station relays. The 5G system shall be able to support means, for a mobile network operator, to configure, provision and control the operation of a mobile base station relay, e.g. activation/deactivation, permitted location(s) or time of operation. The 5G system shall be able to support provisioning and configuration mechanisms to control UEs’ selection and access to a mobile base station relay, e.g. based on UE’s authorization, geographic or temporary restrictions, relay’s load. The 5G system shall be able to support RAN sharing between multiple PLMNs for UEs connected to the 5G network via mobile base station relays. NOTE 1: the above requirement assumes both relay and (donor) RAN resources, including UE access link and relay backhaul link, are shared among operators. The 5G system shall be able to configure and provision specific required QoS for traffic relayed via a mobile base station relay. NOTE 2: QoS is end-to-end, i.e. from UE to 5GC. Subject to regulatory requirements and based on operator policy, the 5G system shall support means to configure and expose monitoring information of a mobile base station relay to an MNO’s authorized third-party. The 5G system shall be able to provide means to optimize network behaviour to efficiently deliver data based on the mobility information (e.g., itinerary), known or predicted, of mobile base station relays. The 5G system shall be able to support communication from/to users of one MNO (MNO-A) via mobile base station relays, where the traffic between the relay and the MNO-A network is transported using 5G connectivity (RAN and 5GC) provided by a different MNO (MNO-B). NOTE 3: The 5G connectivity provided to the MNO-A relays by the different MNO (MNO-B) assumes a generic wireless backhaul transport, independent from the mobile base station relay functionalities. The 5G system shall be able to support UEs connectivity to RAN using simultaneously, a link without mobile base station relay and a link via a mobile base station relay, or simultaneous links via different mobile base station relays. NOTE 4: The above requirements cover scenarios were the two links (to the RAN) could be connected to the same or different RAN node(s), and assuming both relay(s) and RAN belong to the same PLMN. The 5G system shall be able to provide means to support efficient UE cell selection and cell reselection (between mobile base station relays or between relays and RAN) in the presence of mobile base station relays. The 5G system shall be able to ensure end-to-end service continuity, in the presence of mobile base station relays. NOTE 5: The above requirement intends to cover different scenarios of UE mobility (e.g. UE moving between two mobile base station relays, or between macro RAN and relay) and relay mobility (e.g. base station relay moving between different donor RAN nodes). The 5G system shall be able to support mechanisms to optimize mobility and energy efficiency for UEs located in a vehicle equipped with a base station relay. NOTE 6: The above requirements cover scenarios where mobile base station relays provide 5G access for both UEs in the vehicle and around the vehicle. The 5G system shall be able to support incremental deployment of connectivity by means of one or a series of mobile base station relays for use only in specific locations where UEs would receive no other 3GPP access (terrestrial or non-terrestrial) coverage, e.g., for public safety scenarios. The 5G system shall be able to support mobile base station relays using 3GPP satellite NG-RAN (NR satellite access). The 5G system shall be able to support mobile base station relays accessing to 5GC via NR satellite access and NR terrestrial access simultaneously. The 5G system shall be able to support service continuity for mobile base station relays using at least one 3GPP satellite NG-RAN. NOTE 7: This requirement applies to scenarios where there is a transition between two 3GPP NG-RAN, operated by the same MNO, involving at least one 3GPP satellite NG-RAN. The 5G system shall be able to identify and differentiate UEs’ traffic carried via a mobile base station relay and collect charging information, including specific relay information (e.g. geographic location served by the relay). The 5G system shall support means for a mobile base station relay to have a certain subscription with a HPLMN, used to get access and connectivity to the HPLMN network (via a donor RAN). The 5G system shall support the ability of a base station relay to roam from its HPLMN into a VPLMN. The 5G system shall support mechanisms, for the HPLMN controlling a mobile base station relay, to enable/disable mobile relay operation if the relay is roaming in a VPLMN. The 5G system shall support mechanisms to disable mobile relay operation by a VPLMN where a mobile base station relay is roaming to. The 5G system shall be able to fulfil necessary regulatory requirements (e.g. for support of emergency services) when UEs access the 3GPP network via a mobile base station relay. The 5G system shall be able to support priority services (e.g. MPS) when UEs access the 3GPP network via a mobile base station relay. The 5G system shall be able to support location services for the UEs accessing 5GS via a mobile base station relay. The 5G system shall ensure that existing end-to-end 5G security between the UE and 3GPP network is unaffected when the UE accesses the 3GPP network via a mobile base station relay. The 5G system shall be able to minimize radio interference possibly caused by mobile base station relays. The 5G system shall minimize the impact of the presence of mobile base station relays on radio network management (e.g. through automatic neighbour cell list configuration).