Section: 4.16.12.1.1 UE Policy Association Modification initiated by the AMF without AMF relocation
Content: This procedure addresses the scenario where a Policy Control Request Trigger condition is met. Figure 4.16.12.1.1-1: UE Policy Association Modification initiated by the AMF This procedure concerns both roaming and non-roaming scenarios. In the non-roaming case the V-PCF is not involved. In the roaming case, the AMF interacts with the V-PCF and the H-PCF interacts with the V-PCF. 1. When a Policy Control Request Trigger condition is met the AMF updates UE Policy Control Association and provides information on the conditions that have changed to the PCF. The AMF sends a Npcf_UEPolicyControl Update Request with the following information: UE Policy Association ID associated with the SUPI defined in TS 29.525[ 5G System; UE Policy Control Service; Stage 3 ]  [58] and the Policy Control Request Trigger met. In roaming scenario, based on operator policies, the AMF may provide to the V-PCF the PCF ID of the selected H-PCF. The V-PCF contacts the H-PCF. See clause 6.1.2.5 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20] and clause 4.2.3.2 of TS 29.525[ 5G System; UE Policy Control Service; Stage 3 ]  [58] for more details on Policy Control Request Trigger. In the roaming case, steps 2 and 3 are executed, otherwise step 4 follows. 2. The V-PCF forwards the information received from AMF in step 1 to the (H-)PCF. 3. The H-PCF replies to the V-PCF. 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]. 4. The (V-) PCF sends a Npcf_UEPolicyControl Update Response to the AMF. 5. The (H-)PCF may create the UE policy container including UE policy information as defined in clause 6.6 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 include the UE policy container in the Npcf_UEPolicyControl UpdateNotify Request. 6. The (V-)PCF sends a response to H-PCF using Npcf_UEPolicyControl UpdateNotify Response. 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.