Content for TS 23.256 Word version: 19.0.0

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5.2.7 UUAA Revocation by USS/UTM
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5.2.7 UUAA Revocation by USS/UTM p. 54

Reproduction of 3GPP TS 23.256, Fig. 5.2.7.1-1: Procedure for UAV authorization revocation by USS

Figure 5.2.7.1-1: Procedure for UAV authorization revocation by USS

UAS NF stores the UAV UE's UUAA context after successful UUAA procedure as explained in clause 5.2.2.2 for UUAA-MM and in clause 5.2.3.2 for UUAA-SM procedure.

Step 1.

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.

Step 2.

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.

Step 4.

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.

Step 5a.

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.

Step 5b.

The AMF acknowledges the un-subscription request from 5a by sending Namf_EventExposure_Unsubscribe response.

Step 6.

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 4.2.3.3 of TS 23.502.

Step 7a.

If the target NF is AMF, the AMF shall initiate UE Configuration Update procedure as described in clause 4.2.4.2 of TS 23.502 to inform the UE that UUAA is revoked. The AMF shall also initiate the release of PDU Sessions related to UAS services.

Step 7b.

If the target NF is AMF, based on network policy the AMF may start network initiated de-registration process as described in clause 4.2.2.3.3 of TS 23.502.

Step 7c.

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.