Content for  TR 22.839  Word version:  18.1.0

This use case covers certain deployment scenarios where traffic exchanged via vehicle relays for users of one MNO or service provider is carried over a transport 5G network managed by a second MNO. An example is illustrated in fig.1, where the MNO2 provides wireless access and transport between vehicle relays and the MNO1 5G network, allowing E2E connectivity to MNO1 users.

Such scenarios can be based on business agreements among the two parties, specific NW deployment/operational constraints, coverage requirements, etc. For example, it could be used for:

• A 5G mobile operator (MNO1), with limited macro-RAN deployment and coverage footprint, willing to exploit their spectrum to offer 5G access and services to their subscribers (travelling in vehicles, or located in specific hotspot areas). MNO1 could decide to leverage the better/ubiquitous 5G wireless (and transport) connectivity provided by a second operator (MNO2) to tunnel the MNO1 traffic to/from the vehicle relays.
• Public Safety providers or other service/fleet operators, who could manage specific vehicles with on-board relays, together with ad-hoc 5G subscriptions and connectivity services for certain user categories, e.g. for first-responders, delivery personnel, public passengers etc. They may not necessarily own 5G spectrum, or RAN/network infrastructure, thus using MNO2's mobile network to reach connectivity to their relays (and users).

For this use case, the following options are assumed:

• The access link between MNO1 UEs and the vehicle relay uses MNO1 spectrum; the relay can connect to the MNO2 RAN using MNO2 spectrum.
• The MNO2 transport connection, between the vehicle relay and the MNO1 network, is used to carry relay traffic between the vehicle relay and MNO1 5GC.

1. Vehicle relays are provisioned and configured to register to the MNO2 network and establish necessary PDU session(s), with certain quality of service and policies (as negotiated for MNO1 traffic and subscribers).
2. Vehicle relays are provisioned and configured to connect to the donor MNO1 network for communication between MNO1 users and MNO1 network.
3. MNO1 subscribers/UEs inside the vehicle camp on the mobile relays, which will broadcast MNO1 PLMN-ID, and are able to register and connect to the MNO1 network.
4. All traffic generated via vehicle relays by MNO1 UEs is tunnelled through the established relays' MNO2 5G connectivity.

MNO1 users can exploit their 5G service and the good in-vehicle 5G coverage/connectivity provided by the vehicle relays, fully transparently.

TS 23.501 (Annex D) describes the concept of overlay network connection on top of underlay network connection, which does not fully cover the target use case and requirements, intended to be specific to mobile BS relays.

[PR 5.20-1]

Vehicles with onboard base stations, so called vehicle-mounted relays (VMR), are expected to act as relay and help provide efficient data delivery. This use case addresses the needs of users who are not moving with the vehicle-mounted relay but that can benefit from its offered connectivity when users and vehicle-mounted relays are close. In particular, this use case addresses the needs of those UEs that either have limited connectivity (e.g., when connected to a macro cell) or that have too demanding bandwidth needs. Our first use case is about a user, Tom, an emergency physician who just arrived at a car accident. Tom is attending several injured persons. Tom is having a call with other clinicians at a close-by hospital discussing the health state of the patients and to which hospital the patients should be transferred. Tom would also like to retrieve the Electronic Health Record (EHR) of the patients to do a better assessment. However, the network connectivity at his current location - the accident area -- is insufficient, in particular, to download some bulky files in the EHR of the patients. In this situation, it is beneficial if the 5G system can schedule the transfer of the EHR content requested by Tom so that the EHR is transferred by means of a relay mounted on one of the ambulances approaching the accident area. This example is shown in Figure x-1 where the ambulance is denoted AMR, i.e., Ambulance-Mounted Relay. In Figure x-1 Tom's UE is denoted UE. At location L0 and time T0 the EHR data transfer is requested by the UE. The data is then transferred when the AMR is at location L2 since at this location the communication link between donor gNB and AMR and between AMR and UE offer the best end-to-end performance. The location is chosen by using, known or predicted, the AMR mobility pattern to optimize the network behaviour. In some cases, the AMR could receive the EHR data from the donor gNB at location L1 and time T1 and when the AMR is at location L3 at time T3, the AMR could rapidly deliver the requested EHR data to Tom's UE. In this alternative approach, the locations L1 and L3 are chosen to optimize the individual link performance between donor gNB and AMR and between AMR and UE. The choice of these locations is also based on the known or predicted AMR mobility pattern.

Other relevant and related use cases include:

• IoT devices requiring the delivery of a software update. Some IoT devices might lack a good connection but be able to retrieve the software update from a vehicle-mounted relay, when it is close by.
• Users requiring access to bulky resources, e.g., a movie, but with insufficient connectivity at their current location. Users might retrieve the files from an approaching vehicle-mounted relay selected based on the mobility pattern of the VMR.

• An MNO operates AMRs and macro cells in a city.
• The user, Tom, has a UE and is subscribed to the MNO.
• The user, Tom, is connected to a macro base station and Tom needs to retrieve certain files.

• Tom is connected to the 5G macro network.
• Tom performs a call and tries to retrieve the EHR files of the patients.
• The 5G macro network is capable of delivering Tom's normal communication needs, in particular, low bandwidth communication needs. The 5G macro network offers limited capacity for the download of large amounts of data due to spotty coverage and a high number of UEs at Tom's location.
• The MNO operates AMRs that offer extra additional capacity. The mobile network determines that the download needs of our user Tom can be fulfilled by an AMR, an ambulance, approaching Tom's location.
• The 5G system delivers the downlink traffic required by Tom to the ambulance that is approaching Tom's location. The transfer of this EHR content to the ambulance and from the ambulance to Tom's UE is done very fast since this is done where and when the communication links between macro gNB, AMR, and UE are expected to offer the best performance based on the known or predicted mobility pattern of the AMR.
• When the ambulance moves away, Tom's UE releases its connection with the AMR.

• Tom was able to retrieve the required EHR files in an efficient way so that he can attend the patients properly.

From clause 6.2.2 of TS 22.261: "The 5G network shall allow operators to optimize network behaviour (e.g. mobility management support) based on the mobility patterns (e.g. stationary, nomadic, spatially restricted mobility, full mobility) of a UE or group of UEs." However, this requirement is not based on mobility information of vehicle-mounted relays. Clause 6.6 of TS 22.261 (Efficient content delivery) includes various requirements on efficient content delivery. However, these requirements are not based on mobility information of vehicle-mounted relays.

[PR 5.21-1]