4.22.2 Authentication and authorization of UAV

The 5GS supports the USS UAV Authorization and Authentication (UUAA) procedure for a UE supporting UAS services. Depending on operator policy or regulatory requirements, the UUAA-MM procedure can be performed by the UE and the AMF at a registration procedure as specified in clause 5.5.1, the UUAA-SM procedure can be performed by the UE and the SMF at a PDU session establishment procedure as specified in clause 6.4.1.2, or both can be performed. The UE shall support UUAA-MM and UUAA-SM, and the network shall support UUAA-SM and may optionally support UUAA-MM. The UUAA procedure needs to be performed by 5GS with USS successfully before the connectivity for UAS services is established.

During the registration procedure as described in clause 5.5.1, the UE supporting UAS services provides CAA-level UAV ID to the AMF, and the AMF may trigger the UUAA-MM procedure. If the UE supporting UAS services does not provide CAA-level UAV ID to the AMF and the network is configured to perform UUAA-MM at registration procedure, the AMF may accept the registration request and shall mark in the UE's 5GMM context that the UE is not allowed to request UAS services. If the UE wants to use the UAS services by providing the CAA-level UAV ID later on, the UE shall perform the registration procedure for mobility and periodic registration update.

When a UE supporting UAS services requests to establish a PDU session as described in clause 6.4.1.2 for USS communication, the UE provides CAA-level UAV ID to the network, and the SMF may trigger the UUAA-SM procedure based on the DNN and S-NSSAI combination for aerial services according to the user's subscription data and the CAA-level UAV ID provided by the UE.

If the UE does not provide CAA-level UAV ID and the user’s subscription data for the UE requires the UUAA-SM, the network rejects the UE-requested PDU session establishment procedure for the UAS services.

The UE supporting UAS services shall not provide CAA-level UAV ID to the network over non-3GPP access, and the network shall not perform UUAA procedure for non-3GPP access and shall ensure that the UE is not allowed to access any aerial services in non-3GPP access.

If provided by the upper layers, the UE supporting UAS services provides to the network the USS address during the registration procedure or PDU session establishment procedure so that the network uses the information to discover the USS.

NOTE 1: Based on the current location of the UAV, upper layers can select the USS address from the list of USS addresses, where each entry contains a USS address and a corresponding geographical area.

NOTE 2: The parameters (e.g. CAA-level UAV ID or USS address) sent by a UE supporting UAS services to the network for UAS services are included in the Service-level-AA container IE which is a non-cleartext IE.

After successful UUAA procedure, either the AMF or the SMF may initiate re-authentication of the UAV when required by the USS. If UUAA-MM fails during a re-authentication and there are PDU sessions established using UAS services, the AMF shall request the SMF to perform the release of these PDU sessions and may trigger a network-initiated de-registration procedure based on operator policy. If UUAA-SM fails during a re-authentication, the SMF shall release the PDU session related to re-authentication.

If the UUAA is revoked, the PDU session related to the UAS services shall be released by the SMF. Based on operator policy, the AMF may decide to keep the UE registered or trigger a de-registration procedure.