Content for  TS 23.256  Word version:  18.2.0

If the UAV is capable of 3GPP network connection and is served by a PLMN, the UAV performs the Direct C2 Communication authorization either as part of the UUAA-MM procedure in 5GS described in clause 5.2.2 or as part of the C2 Authorization during UUAA-SM procedure described in clause 5.2.5. In either case, if the UAV supports Direct C2 Communication and intends to request C2 authorization for Direct C2 Communication to the USS, it shall include an indication for Direct C2 Communication authorization in the authorization request. If the UAV is not capable of 3GPP network connection or is not in coverage of a PLMN at the moment of performing authorization of Direct C2 Communication, or when the UAV does not use any PLMN resources for UAS services, Direct C2 Communication is authorized based on pre-configured policies in the UAV (e.g. at the application layer).

In 5GS, the UUAA-MM procedure may be used to authorize direct C2 communication described in clause 5.2.2 with the following enhancements:

• In step 1 of clause 5.2.2.1: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the UAV may include an authorization request for Direct C2 Communication by providing a C2 Aviation Payload with an indication that the authorization is for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
• In steps 2 and 3 of clause 5.2.2.2: if the UAV included the C2 Aviation Payload in step 1 of clause 5.2.2.1, the C2 Aviation Payload is also included
• In steps 5 and 6 of clause 5.2.2.2: If the authorization request for Direct C2 Communication was included in step 1 of clause 5.2.2.1, the USS sends the C2 Authorization result and in the case of success, may include a direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload, which are further forwarded to the UAV/UE.

If the UAV attempts Direct C2 Communication authorization via UUAA-MM and receives no response, the UAV shall perform Direct C2 Communication via UUAA-SM.

In 5GS, the following procedures are used to request C2 authorization for Direct C2 Communication to the USS:

• The procedure for C2 Authorization request during UUAA-SM procedure in 5GS as specified in clause 5.2.5.2.1 with the following enhancements:
  • In step 0: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 4: If the authorization request for Direct C2 Communication was included in step 0 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UAV/UE.
• The procedure for UE initiated PDU Session Modification for C2 Communication as specified in clause 5.2.5.2.2 with the following enhancements:
  • In step 2: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 6: If the authorization request for Direct C2 Communication was included in step 2 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UAV/UE.
• The procedure for UE initiated PDU Session Establishment for C2 Communication as specified in clause 5.2.5.2.3 with the following enhancements:
  • In step 1: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 4: If the authorization request for Direct C2 Communication was included in step 1 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UE in the Naf_Authentication_AuthenticateAuthorize response.

In EPS, the following procedures are used to request C2 authorization for Direct C2 Communication to the USS:

• The procedure for C2 Authorization request during UUAA-SM procedure in EPS as specified in clause 5.2.5.3.0 with the following enhancements:
  • In step 0: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 5: If the authorization request for Direct C2 Communication was included in step 0 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UAV/UE.
• The procedure for UE requested PDN connectivity for C2 authorization as specified in clause 5.2.5.3.1 with the following enhancements:
  • In step 1: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 4: If the authorization request for Direct C2 Communication was included in step 1 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UAV/UE.
• The procedure for UE requested bearer resource modification of an existing PDN connection for C2 authorization as specified in clause 5.2.5.3.2 with the following enhancements:
  • In step 1: When the UAV needs to establish a direct PC5 link required for connectivity to UAV-C (i.e. Direct C2 Communication), the C2 Aviation Payload sent by the UAV includes an indication that the authorization is also for Direct C2 Communication. In addition, the UAV includes the direct C2 pairing information (if available) in the C2 Aviation Payload.
  • In step 4: If the authorization request for Direct C2 Communication was included in step 1 and the C2 authorization is successful, the USS may include direct C2 pairing information containing the UAV-C's Application Layer ID in the C2 Authorization Payload which is further forwarded to the UAV/UE.