Content for  TR 22.843  Word version:  19.2.0

3GPP has specified a wide range of aerial features, activated through an "aerial subscription". Three types of C2 communications have been defined for R17, in TS.22.125 [3]:

• Direct C2 communications (when the UAV controller and UAV establish a direct C2 link to communicate with each other);
• Network-Assisted C2 communications (when the UAV controller and UAV communicate with each other via 5G network);
• UTM-Navigated C2 communication (for pre-scheduled autonomous flights).

3GPP features for Network-Assisted C2 communications and UTM-Navigated C2 communication mostly cover Beyond Visual Line-of-Sight (BVLoS) UAV operations, and Direct C2 communications are constrained by their radio coverage range, which is generally much wider than the VLoS constraints imposed by airspace authorities. In all three cases, it is thus technically possible that an UAV controller does not comply with airspace regulatory requirements related to VLoS operations. Ensuring that an aerial UE is complying with regulatory Visual Line-of-Sight constraints, by supporting pre-flight preparations and inflight operation flight monitoring and control, enhances the safety and security of UAV operations. There is a need to enable the 5G system to be aware if VLoS constraints should be applied to UAV operations, and if so, to monitor the relative positions of an aerial UE with respect to its pilot to ensure that this aerial UE is complying with Line-of-Sight constraints.

The UAV is associated with an aerial UE profile and a "VLoS" option is activated together with its subscription. The UAV is associated with an UAV Controller (UAV-C). The 5G system is informed by the UTM of the maximal distance authorized between the UAV and the UAV-C (VLoS distance threshold, usually around 200 or 300m), which usually depends on airspace regulation and may potentially account for other conditions (e.g. weather, type of environment, type of UAV, temporary or localized special authorization, etc.).

1. The UAV registers in 5GS as an aerial UE with the VLoS option activated.
2. The UAV is associated with an UAV-C. The UAV takes off.
3. The network tracks the geolocalization of both the UAV and UAV-C, and deduces the distance between both. If the UAV-C does not belong to the 3GPP system, its geolocalization may be obtained, for example, from the USS/UTM.
4. In case this distance exceeds the VLoS threshold, the network takes action, e.g. alerts the UTM and/or lets the UTM takes over the communication used to bring back the UAV within the authorized VLoS constraints, or sends a new waypoint within the authorized VLoS constraints.

The UTM may take over the communication used to control the UAV and force the UAV to land safely.

• "Aerial subscription" option in subscription, as specified in Rel-15;
• UAV / UAV-C association, as in TS 23.256 for example;
• Tracking of the geolocalization of the UAV as in TS 23.256 for example.

[PR 5.3.6-001] [PR 5.3.6-002] [PR 5.3.6-003] [PR 5.3.6-004]