UAS NF stores the UAV UE's UUAA context after successful UUAA procedure as explained in clause 188.8.131.52
for UUAA-MM and in clause 184.108.40.206
for UUAA-SM procedure.
The USS sends Naf_Authentication_Notification to UAS NF for authorization revocation. The USS includes GPSI, CAA-Level UAV ID, cause of revocation, PDU Session IP address if available in the authorization revocation request.
UAS NF retrieves the UAV UE's stored UUAA context. From the stored UUAA context the UAS NF determines the target AMF or SMF for sending the notification.
Step 3a or 3b.
The UAS NF sends Nnef_Authentication_Notification request to notify the target NF, i.e. either the AMF or the SMF that the UAV is not authorized anymore, indicating the cause is revocation. The target NF shall remove the successful UUAA result and respond to the UAS NF.
The UAS NF shall remove the UAV UE's UUAA context. The UAS NF responds back to the USS indicating that authorization revocation request has been successfully initiated.
If UAS NF has subscribed to AMF for the Mobility Event Exposure with Event ID = Reachability Filter before, UAS NF unsubscribes to AMF for the mobility event notification by sending Namf_EventExposure_Unsubscribe request with Subscription Correlation ID.
The AMF acknowledges the un-subscription request from 5a by sending Namf_EventExposure_Unsubscribe response.
If UE is in CM_Idle state, the target NF (i.e. either the AMF or the SMF) initiates the Network Triggered Service Request procedures as described in clause 220.127.116.11 of TS 23.502
If the target NF is AMF, the AMF initiates UCU procedure to inform the UE that UUA is revoked. The AMF shall also initiate the release of PDU Sessions related to UAS services.
If the target NF is AMF, based on network policy the AMF may start network initiated de-registration process as described in clause 18.104.22.168.3 of TS 23.502
If the target NF is SMF, the SMF starts network initiated PDU session release process as described in clause 4.3.4 of TS 23.502
to release the associated PDU session.
If USS determines that UAV controller replacement is required the USS invokes an Nnef_AFsessionWithQoS_Update
service operation to the UAS NF including in the request authorization information (i.e. new pairing information). NEF authorizes the request from the USS followed by interacting with PCF triggering a Npcf_PolicyAuthorization_Update
request and provides relevant parameters to the PCF. The PCF uses the information provided by the NEF to derive new PCC rules to allow C2 communication between the UAV and the new UAV controller.
The procedure for UAV-C replacement is as follows:
A UAV has already established user plane connectivity for C2 operation. The USS determines that the UAV-C controlling the UAV needs to be replaced (e.g. if the UAV is misbehaving).
The USS initiates the UAV-C replacement by invoking the Nnef_AFSessionWithQoS_Update
request including Transaction Reference ID, UAV-UAVC Pairing info/Flow description(s), QoS reference. See step 1 in TS 23.502, clause 22.214.171.124a
, AF session with required QoS update procedure.
NEF authorizes the request from the USS followed by interacting with PCF triggering a Npcf_PolicyAuthorization_Update
request and provides relevant parameters to the PCF. PCF determines whether the request is authorized and if the requested QoS is allowed. PCF informs NEF if the request is accepted by invoking Npcf_PolicyAuthorization_Update
Response. See Steps 2 - 4 in TS 23.502 Figure 126.96.36.199a-1
NEF sends a Nnef_AFsessionWithQoS_Update
response message (Transaction Reference ID, Result) to the USS. Result indicates whether the request is granted or not. See step 5 in TS 23.502 Figure 188.8.131.52a-1
USS invokes the UAV Re-authorization procedure in Figure 184.108.40.206-1
to deliver the new pairing information to the UE. The USS includes the 3GPP UAV ID, the IP address of the PDU session and included in the authorization message the C2 Authorization Result and the C2 Authorization Payload (containing the C2 pairing information containing the new UAV-C identifier and C2 security information) which is further forwarded to the UE.
The procedure for UAV-C replacement in EPS is as follows:
UAV is attached to EPC with a PDN connection established
The USS determines that the UAV-C controlling the UAV needs to be replaced (e.g. if the UAV is misbehaving).
USS initiates the Nnef_AFSessionWithQoS_Update
request including USS Identity/AF Identifier, Transaction Reference ID, UAV-UAVC Pairing info/Flow description(s), QoS reference. Steps 1-3 as in Figure 220.127.116.11-1
The PCF determines updated policy information and configures the resources and routing information as in steps 2 - 4 in Figure 18.104.22.168.2-1
The USS is informed whether the UAV-C replacement and authorization has succeeded or failed as in steps 6- 7 in Figure 22.214.171.124.1-1
The USS invokes the UAV re-authorization procedure in EPS as in Figure 126.96.36.199-1
. The USS includes the 3GPP UAV ID, the IP address of the PDU session and included in the authorization message, the C2 Authorization Result and the C2 Authorization Payload (e.g. containing the C2 pairing information containing the new UAV-C identifier and C2 security information) which is further forwarded to the UE.