For a UE that requires UUAA or when triggered by re-authentication by USS, the AMF triggers a UUAA-MM procedure. If the UE does not have an Aerial subscription in the UE subscription data retrieved from the UDM, the AMF shall not trigger a UUAA-MM procedure.
AMF to UAS NF/NEF: The AMF invokes Nnef_Authentication_AuthenticateAuthorize
Request message. For initial authentication, this shall include the GPSI and the CAA-Level UAV ID and may include USS address (e.g. FQDN), UUAA Aviation Payload if it was provided by the UE. For re-authentication triggered by AMF, this may not include the CAA-Level UAV ID. UAS NF resolves the USS address based on CAA-Level UAV ID or uses the provided USS address, as described in clause 4.4.2
. In addition, the AMF may also include the User Location Information (e.g. Cell ID). The UAS NF should store the serving AMF ID.
The AMF identifies the UAS NF/NEF based on local configuration or by NF discovery procedure using DNN/S-NSSAI and/or UE provided identity e.g. USS address.
The AMF also provides a Notification Endpoint to the UAS NF/NEF, so that UAS NF/NEF can include this Notification Endpoint together with UUAA updated parameters, as shown in clause 5.2.4
. By providing the Notification Endpoint, the AMF is implicitly subscribed to be notified of re-authentication, update authorization data or revocation of UAV from UAS NF/NEF, if the UUAA result is successful in step 5.
UAS NF/NEF to USS: Naf_Authentication_AuthenticateAuthorize
Request message, shall include the GPSI and CAA-Level UAV ID and optionally UAV location obtained from AMF in step 2 e.g. to support geo-caging functionality. UAS NF/NEF may translate the Cell ID received as UAV location from AMF in step 2 into a corresponding geographic area and/or may further obtain the UE location information using Location Service Procedures as defined in TS 23.273
The UAS NF/NEF also provides a Notification Endpoint to the USS, so that USS can include this Notification Endpoint together with UUAA updated parameters, as shown in clause 5.2.4
. By providing the Notification Endpoint, the UAS NF/NEF is implicitly subscribed to be notified of re-authentication, update authorization data or revocation of UAV from USS, if the UUAA result is successful in step 5.
[Conditional] Multiple round-trip messages as required by the authentication method used by USS. Naf_Authentication_AuthenticateAuthorize Response messages from USS shall include GPSI and shall include a authentication message based on authentication method used that is forwarded transparently to UE over NAS MM transport messages. The authentication message in step4d may contain UUAA Aviation Payload required by the USS if it was not provided by the UE before.
USS to UAS NF/NEF: (final) Naf_Authentication_AuthenticateAuthorize Response message, shall include: GPSI, a UUAA result (success/failure) for the UAV and the UAS NF, may include an authorized/new CAA-Level UAV ID for the UAV and a UUAA Authorization Payload to the UAV (e.g. security info to be used to secure communications with USS), and a final authentication message (e.g. indicating success or failure, and if the UUAA is for re-authentication, indicating whether the UAS service related network resource can be released in case of UUAA failure) based on authentication method used that is forwarded transparently to UE over NAS MM transport messages.
UAS NF/NEF to AMF: (final) Nnef_Authentication_AuthenticateAuthorize Response message, forwards information received from USS in step 5. If UUAA for re-authentication failed and UAS NF/NEF received indication that the UAS service related network resource can be released in step 5, the UAS NF/NEF includes an indication that the PDU sessions associated with the "DNN(s) subject to aerial services" can be released.
[Conditional] UAS NF/NEF to AMF: If UUAA-MM succeeded and UAS NF/NEF has not subscribed to AMF for the Mobility Event Exposure before, UAS NF/NEF subscribes to AMF for the mobility event notification by sending Namf_EventExposure_Subscribe
request with the mobility events as described in TS 23.502
, Table 126.96.36.199.1-1
with Event ID = Reachability Filter.
[Conditional] UAS NF/NEF to AMF: If UUAA-MM failed and UAS NF/NEF has subscribed to AMF for the Mobility Event Exposure earlier, UAS NF/NEF unsubscribes to AMF for the mobility event notification by sending Namf_EventExposure_Unsubscribe request with Subscription Correlation ID.
[Conditional] AMF to UAS NF/NEF: The AMF acknowledges the subscription request from 7a by sending Namf_EventExposure_Subscribe response with Subscription Correlation ID.
[Conditional] AMF to UAS NF/NEF: The AMF acknowledges the un-subscription request from 7b by sending Namf_EventExposure_Unsubscribe response.
AMF to UE: (final) NAS MM transport message forwarding authentication message from USS including authentication/authorization result (success/failure).
[Conditional] if UUAA-MM succeeded, AMF triggers a UE Configuration Update procedure to deliver to the UAV authorization information from USS, as described in clause 188.8.131.52
[Conditional] If UUAA-MM fails during a Re-authentication and Re-authorization and there are PDU session(s) established using UAS services, and the USS has indicated that the network resources can be released, AMF may trigger these PDU Sessions release. AMF identifies the relevant PDU session(s) for UAS services based on the DNN/S-NSSAI value of the PDU session.
[Conditional] if UUAA-MM fails, based on network policy the AMF may trigger Network-initiated Deregistration procedure described (as specified in clause 184.108.40.206.3 of TS 23.502
) and it shall include in the explicit De-Registration Request the appropriate rejection cause value.
If there is an AMF relocation for the UAV, the new serving AMF shall notify the UAS NF about the new AMF ID and the related CAA-level UAV ID using the existing AMF event notification service.
At any time after the initial registration, the USS (via UAS NF/NEF) or the AMF may initiate Re-authentication procedure for the UAV. For AMF initiated case the Re-authentication procedure shall start from step 2. USS initiated re-authentication procedure is described in
, then the AMF shall unsubscribe to UAS NF and then UAS NF/NEF may clear the UUAA-MM context and update USS.