Roaming UE-AMBR Control via AMF and V-PCF Policy
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Solution Overview
Problem
In a roaming scenario, there is no logic for the Visited Public Land Mobile Network (VPLMN) to control or adjust the UE-AMBR, as the AMF has mobility control at the UE level but is transparent to session-related policy, and the Visited Session Management Function (V-SMF) lacks an overview of UE-level policies.
Innovation Solution
The AMF in the serving network obtains both the subscribed UE-AMBR from the UDM and a policy-based UE-AMBR from the V-PCF, determining and deploying the smaller of the two to enforce UE-AMBR policy in the RAN, allowing the VPLMN to steer UE-AMBR via policy-based parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the AMF is used for mobility control at UE level, then mobility management efficiency is improved, but session policy control capability deteriorates because the AMF is transparent to session-related policy
Solution Approach 1:
The patent introduces the PCF as an intermediary function that bridges the AMF and session policy requirements. The PCF receives policy parameters from the VPLMN and translates them into session policy controls that the AMF can enforce, allowing the AMF to maintain its mobility management efficiency while gaining session policy control capability through the PCF intermediary
2Measurement precision
If the V-SMF is used for session management, then session management precision is improved, but UE-level policy overview capability deteriorates because the V-SMF only sees PDU session level information
Solution Approach 1:
The patent merges the policy control functions at the PCF level, combining both session management precision (from V-SMF) and UE-level policy overview (from AMF) into a unified policy control mechanism. The PCF aggregates information from multiple PDU sessions and UE context to provide comprehensive UE-level policy control while maintaining session management precision
3Reliability
If the subscribed UE-AMBR is used for UE level AMBR control, then UE subscription rights are preserved, but VPLMN policy control capability deteriorates because there is no logic for VPLMN to steer the policy
Solution Approach 1:
The patent makes the UE-AMBR dynamic by introducing policy parameters from VPLMN that can adjust the effective UE-AMBR based on roaming conditions. The system transitions from a static subscribed UE-AMBR to a dynamic effective UE-AMBR that adapts to VPLMN policies while maintaining the subscription rights as a baseline
Solution Approach 2:
The patent changes the parameter control mechanism by introducing policy parameters from VPLMN that modify the UE-AMBR value. The system transforms the fixed subscribed UE-AMBR parameter into a flexible effective UE-AMBR that can be adjusted through policy parameters, enabling VPLMN control while preserving subscription rights
Data Source
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AI summary
Disclosed herein is a method performed by an AMF entity 1100 in a Visited Public Land Mobile Network, VPLMN, entity serving a roaming UE 112, the method comprises: obtaining NN102, by the AMF entity, a subscribed UE-AMBR for the UE; sending XX102, XX200, XX304, by the AMF entity, an Access Management, AM, Policy request message towards a Visited Policy Control Function, V-PCF, entity 1200 in the VPLMN to establish or update an AM Policy for the roaming UE; receiving XX104, XX204, XX306 by the AMF entity in response to sending the AM Policy request message, an AM Policy response message sent by the V-PCF entity and comprising Access and mobility related policy information that includes a serving network UE-AMBR for the UE decided by the V-PCF entity; and deploying XX106, XX206, XX308 the serving network UE-AMBR instead of the subscribed UE-AMBR by sending the policy control information including the determined UE-AMBR to a RAN node in the serving network.