Section: 4.16.12.2 UE Policy Association Modification initiated by the PCF
Content: This procedure is used to update UE policy and/or UE policy triggers. In the non-roaming case, the H-PCF may interact with the CHF in HPLMN to make a decision about UE Policies based on spending limits. Figure 4.16.12.2-1: UE Policy Association Modification initiated by the PCF This procedure concerns both roaming and non-roaming scenarios. In the non-roaming case the V-PCF is not involved and the role of the H-PCF is performed by the PCF. In the roaming case, the H-PCF provides UE policy decision and provides the policy to the AMF via V-PCF. 1a and 1b. If (H-)PCF subscribed to notification of subscriber´s policy data change or 5G VN Group Configuration (5G VN group data, 5G VN group membership) change and a change is detected, the UDR notifies that the subscriber´s policy data of a UE or 5G VN Group Configuration (5G VN group data, 5G VN group membership) has been changed. The UDR notifies the (H-)PCF of the updated policy control subscription information profile via Nudr_DM_Notify (Notification correlation Id, Policy Data, either UE context policy control data or Policy Set Entry data or both, SUPI), or The UDR notifies the (H-)PCF of the updated 5G VN Group Configuration (5G VN group data, 5G VN group membership) via Nudr_DM_Notify (Notification correlation Id, 5G VN Group Configuration, Internal-Group-Identifier), or The (V-)UDR notifies the (V-)PCF of the updated policy control subscription information profile via Nudr_DM_Notify (Notification correlation Id, Policy Data, PolicySetEntry Data. PLMN ID). The (V-)UDR notifies the (V-)PCF of the updated Service Parameters via Nudr_DM_Notify. 1c and 1d. PCF determines locally that UE policy information needs to be sent to the UE. 1e The CHF notifies the (H-)PCF about the change of the status of the subscribed policy counters available at the CHF for that subscriber. 2a and 2b. The PCF makes the policy decision. If the group data is updated, the (H-) PCF checks the UE Policy Associations for those SUPIs within the Internal-Group-Id and may need to perform step 3 to step 9 for each UE Policy Association that needs to be updated with new UE Policies sent to each UE. In the non-roaming case, the PCF may subscribe to Analytics from NWDAF as defined in clause 6.1.1.3 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20]. 2c and 2d. In the roaming case, the V-PCF may provide the updated Service Parameters received from the V-UDR as specified in clause 4.15.6.10 to the H-PCF using the Npcf_UEPolicyControl_Update Request. The H-PCF sends a response to the V-PCF. 3. The (H-)PCF may create the UE policy container including UE policy information as defined in clause 6.1.2.2.2 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20]. In the case of roaming, the H-PCF may send the UE policy container in the Npcf_UEPolicyControl UpdateNotify Request. The H-PCF may provide updated policy control triggers for the UE policy association. If there is the received Service Parameters from the V-PCF in step 2, the H-PCF may take the Service Parameters obtained from V-PCF to generate URSP rules applicable in the VPLMN as specified in clause 4.15.6.10. 4. The V-PCF sends a response to H-PCF using Npcf_UEPolicyControl UpdateNotify Response. 5. The (V-)PCF provides the Policy Control Request Trigger parameters in the Npcf_UEPolicyControl UpdateNotify Request to the AMF. In the case of roaming, the V-PCF may also provide UE policy information to the UE. The V-PCF may also provide updated policy control triggers for the UE policy association to the AMF. 6. The AMF sends a response to (V-)PCF. Steps 7, 8 and 9 are the same as steps 8, 9 and 10 of procedure UE Policy Association Establishment in clause 4.16.11.