In certain scenarios, a mobile base station relay mounted on a vehicle may serve UEs outside, and while the vehicle is moving the relay connection to the macro network can change, i.e. can be handed over to a different macro donor node. In such cases, the system should ensure seamless mobility and service continuity.
The example scenario described here refers to an outdoor sport event (bike or pedestrian race), with motorbikes' camera transmitting real-time video via relays mounted on alongside vehicles, e.g. provided by the event organizer or TV broadcaster. During the race, the vehicle relay changes macro cell coverage, i.e. relay connection is handed over between two macro donor nodes.
Before the race starts, cameras on motorbikes get configured and connected to a surrounding vehicle relay, providing 5G wireless backhauling connectivity toward a certain PLMN network.
Real-time video transmission starts, and the vehicle relay is connected to macro cell (donor node) #1.
The sport race starts; motorbikes with cameras and cars equipped with relays follow, on the side, the race group/platoon.
While moving along the race itinerary, the relay coverage and connection quality from macro cell#1 gets weaker, and macro cell#2 becomes a stronger/better cell to connect to.
Based on NW decision, at a certain point the relay backhaul connection is handed over from cell#1 to cell#2, while UEs (cameras) remain connected to the same relay.
The vehicle relay is connected to macro cell#2, and no service disruption occurred to the ongoing video transmission.
Current requirements (e.g. related to wireless self-backhaul, see TS 22.261, clause 6.12
) or existing functionalities (e.g. IAB), cover scenarios of autonomous configuration/adaptation of network topologies, but do not assume or fully address physical relay mobility.
The 5G system shall be able to support efficient handover of a UE active communication when a mobile base station relay (e.g. serving a UE outside a vehicle) changes between macro network nodes, ensuring end-to-end service continuity during mobility of the relay.