Content for  TR 22.865  Word version:  19.2.0

UAM (Urban Air Mobility) refers to a safe and efficient air transport system. UAM is used for transporting passengers or cargo in urban or suburban areas. Recently, in some countries, telecom operators have already started the collaboration with aviation companies for UAM business building from airframes to service platforms [21]. In order to control and manage the UAM body for safe and sound travel, the UAM vehicles should receive various information about the movement of other flying vehicles, climate conditions, location, and so on. Additionally, the UAM vehicle can provide the in-flight Internet service allowing the passengers to communicate with the users in the remote networks and on other flying vehicles as well. Even though the UAM vehicles generally operate at an altitude less than 1km, they may fly over the air out of terrestrial network coverage. Thus, the commercialization of UAM depends on the establishment of a telecommunication network service including LEO satellite communications. While flying out of terrestrial network coverage, the vehicles can communicate with each other via satellite without going through the ground network. But, as a vehicle approaches the ground and hence has a connection to the terrestrial network, the communication between vehicles via satellite should be continuously provided through the satellite and terrestrial network.

UAM company UAM-Co operates many UAM vehicles in urban and suburban areas. UAM company UAM-Co contracts with Terrestrial Operator Ter-OP to provide communication services for the devices on UAM vehicles. UAM company UAM-Co also have signed contract with Sat-OP for communication services via satellite access. Their devices on UAM vehicles can communicate with each other directly via satellite without going through the ground network. Satellite Operator Sat-OP has an agreement with Terrestrial Operator Ter-OP to provide communication services for UEs under satellite coverage. The devices on UAM vehicle A and B have a subscription with the Terrestrial Operator Ter-OP.

1. The devices on UAM vehicle A and B register with the Ter-OP network.
2. UAM vehicle A is flying out of Ter-OP network coverage, thus its device has a connection to the satellite operated by Sat-OP.
3. UAM vehicle B is ready to fly in the ground station, and hence its device has a connection to the Ter-OP network.
4. Before or Just after taking off, UAM vehicle B needs to gather the information on the movement of other flying vehicles including vehicle A. The data traffic between UAM vehicle A and B is routed though the satellite and terrestrial networks.
5. UAM vehicle B keeps gathering the movement information of vehicle A even after it moves out of Ter-OP network coverage. Since the information exchange between UAM vehicles should be performed in real time (with very low latency), the vehicles communicate with each other via satellite directly without going through the ground network.
6. After then, as UAM vehicle B approaches the ground, it has a connection to the terrestrial network.
7. The traffic between UAM vehicle A and B is going through the satellite and terrestrial network.
8. As a result, the communication between UAM vehicle A and B keep going without any discontinuation of service.

User A and B can finish the exchange of their movement information without any discontinuation of communication service regardless of their roaming between satellite and terrestrial network.

3GPP TS 22.261, clause 6.2.4 includes roaming related requirements in diverse mobility management: clause 6.3.2.3 on satellite access includes the following requirement: clause 9.1 on charging aspect includes the following requirement:

[PR 5.15.6-001]