Content for  TS 23.304  Word version:  18.4.0

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).

For PCF based Service Authorization and Provisioning to UE, the Registration procedures as defined in clause 4.2.2.2 of TS 23.502, UE Policy Association Establishment procedure as defined in clause 4.16.11 of TS 23.502 and UE Policy Association Modification procedure as defined in clause 4.16.12 of TS 23.502 apply with the following additions:

• If the UE indicates 5G ProSe Capability in the Registration Request message and if the UE is authorized to use 5G ProSe service based on subscription data, the AMF selects the PCF which supports 5G ProSe Policy/Parameter provisioning as described in clause 6.2.3 and establishes a UE policy association with the PCF for 5G ProSe Policy/Parameter delivery. The AMF reports the authorized 5G ProSe Capability to the selected PCF, which may determine the 5G ProSe Policy/Parameter based on the UE's authorized 5G ProSe Capability.

The PCF may update the 5G ProSe 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 4.16.12.1 of TS 23.502.
• When there is a subscription change in the list of PLMNs where the UE is authorized to perform 5G ProSe services. This is achieved by using UE Policy Association Modification initiated by the PCF procedure as defined in clause 4.16.12.2 of TS 23.502.
• When there is a change of service specific parameter (including path selection policy) as described in clause 6.2.5 (performing the procedure in clause 4.15.6.7 of TS 23.502).
• When the timer associated with some Policy/parameter expires.
• When the UE determines that the ProSe Policy/parameter(s) is invalid and performs UE triggered Policy Provisioning procedure to the PCF.

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 ProSe UE triggered Policy Provisioning procedure to the PCF, after Registration procedure has been completed, as specified in clause 6.2.4 when the UE determines the 5G ProSe Policy/Parameter is invalid (e.g. Policy/Parameter is outdated, missing or invalid). When the UE disables a ProSe capability, the PCF may stop updating the corresponding ProSe Policy/parameter(s) and when the UE enables a ProSe capability the PCF may need to provide or update the corresponding ProSe Policy/parameter(s). When a 5G ProSe Layer-3 Remote UE is accessing to 5GC via a 5G ProSe Layer-3 UE-to-Network Relay without involving N3IWF, the PCF based provisioning and update of 5G ProSe Policy/parameters to the 5G ProSe Layer-3 Remote UE are not supported.

PCF discovery and selection mechanism defined in clause 6.3.7.1 of TS 23.501 applies with the following addition to enable a PCF instance is selected for 5G ProSe 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 5G ProSe 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 UE triggered Policy Provisioning procedure is initiated by the UE to request ProSe Policy/Parameter from the PCF when UE determines the 5G ProSe Policy/Parameter is invalid in the following cases:

• if the validity timer indicated in the 5G ProSe Policy/Parameter expires;
• if there are no valid parameters, e.g. for the 5G ProSe Identifier a UE wants to use, for current area, or due to abnormal situation.

For 5G ProSe service parameter provisioning (i.e. creating, updating and deleting), the procedure defined in clause 4.15.6.7 of TS 23.502 is performed with the following considerations:

• The AF in TS 23.502 is considered as ProSe Application Server in this specification.
• Service Description indicates 5G ProSe service domain information.
• Service Parameters include parameters for 5G ProSe Direct Discovery and 5G ProSe Direct Communications. The detailed information on the parameters is described in clause 5.1.2.1 and clause 5.1.3.1.
• Service Parameters for 5G ProSe UE-to-Network Relay Discovery and 5G ProSe UE-to-Network Relay Communications. The detailed information on the parameters is described in clause 5.1.4.1.
• Service Parameters for 5G ProSe UE-to-UE Relay Discovery and 5G ProSe UE-to-UE Relay Communications. The detailed information on the parameters is described in clause 5.1.5.1.