The procedures for service authorization and provisioning to UE may be initiated by the PCF (as described in clause 6.2.2), by the UE (as described in clause 6.2.4), or by the AF (as described in clause 6.2.5).
If the UE indicates V2X capability in the Registration Request message and if the UE is authorized to use V2X service based on subscription data, the AMF selects the PCF which supports V2X Policy/Parameter provisioning as described in clause 6.2.3 and establishes a UE policy association with the PCF for V2X Policy/Parameter delivery.
If the AMF receives the PC5 capability for V2X in the Registration Request message from UE, the AMF further reports the PC5 capability for V2X to the selected PCF. The PCF may determine the V2X Policy/Parameter for specific PC5 RAT based on the received UE's PC5 capability for V2X.
The PCF may update the V2X Policy/parameters to the UE in following conditions:
UE Mobility, e.g. UE moves from one PLMN to another PLMN. This is achieved by using the procedure of UE Policy Association Modification initiated by the AMF, as defined in clause 126.96.36.199 of TS 23.502.
When there is a subscription change in the list of PLMNs where the UE is authorized to perform V2X communication over PC5 reference point. This is achieved by using UE Policy Association Modification initiated by the PCF procedure as defined in clause 188.8.131.52 of TS 23.502.
If the serving PLMN is removed from the list of PLMNs in the service authorization parameters, the service authorization is revoked in the UE.
When the UE is roaming, the change of subscription resulting in updates of the service authorization parameters are transferred to the UE by H-PCF via V-PCF.
The UE may perform UE triggered V2X Policy Provisioning procedure to the PCF, after Registration procedure has been completed, as specified in clause 6.2.4 when the UE determines the V2X Policy/Parameter is invalid (e.g. Policy/Parameter is outdated, missing or invalid).
PCF discovery and selection mechanism defined in clause 184.108.40.206 of TS 23.501 applies with the following addition to enable a PCF instance is selected for V2X service and for UE:
Based on the indication from the UE and/or UE subscription data during the Registration procedure as specified in clause 6.2.2, the AMF may include the V2X capability indication in the Nnrf_NFDiscovery_Request message as the optional input parameter. If provided, the NRF takes the information into account for discovering the PCF instance.
The PCF receives UE Policy Container which indicates UE Policy Provisioning Request to request V2X policies. If the V2X policies are authorized based on AMF input as specified in clause 6.2.2, the PCF performs the UE Policy delivery procedure defined in clause 220.127.116.11 of TS 23.502.
The V2X Application Server can provision the 5GC with V2X service parameters via NEF as depicted in clause 4.2.2. For V2X service parameter provisioning, the procedure defined in clause 18.104.22.168 of TS 23.502 is performed with the following considerations:
The AF in TS 23.502 is considered as V2X Application Server in this specification.
Service Description indicates V2X service domain information.
Service Parameters include policy/provisioning parameters for V2X communications over Uu and PC5. The detailed information on the parameters is described in clause 5.1.