Policy Charging Control for Multiple PDN Connections in Roaming
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Solution Overview
Problem
Current technologies face challenges in performing effective policy and charging control for multiple PDN connections established to one APN in roaming scenarios due to the complexity of EPS roaming scenarios and the intricacies of policy and charging control.
Innovation Solution
A method is introduced that involves establishing a PDN connection, a first gateway control session, a Gx session, an S9 session, and a first subsession for policy and charging control, with a destination BBERF sending an indication message for a second gateway control session to a visited PCRF, which then requests a second subsession with the home PCRF, associating the Gx session with the second subsession using a PDN connection identifier, and modifying policies according to bearer attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PDN connections are established to one APN in roaming scenarios, then the UE can access multiple services simultaneously, but the policy and charging control complexity increases significantly
Solution Approach 1:
The patent segments the S9 session into multiple subsessions, with each subsession corresponding to a specific PDN connection. This segmentation allows the home PCRF to independently manage policy and charging control for each PDN connection through dedicated subsessions, reducing the overall control complexity while maintaining multi-PDN access capability
Solution Approach 2:
The patent introduces the visited PCRF as an intermediary between the home PCRF and the multiple PDN connections. The visited PCRF receives the S9 session from the home PCRF, segments it into multiple subsessions, and manages the Gx sessions for each PDN connection locally, thereby simplifying the policy and charging control architecture in roaming scenarios
2Loss of energy
If multiple Gx sessions are managed through a single S9 session without subsession segmentation, then the signaling overhead is reduced, but the association between Gx sessions and PDN connections becomes ambiguous
Solution Approach 1:
The patent segments the single S9 session into multiple subsessions, where each subsession maintains a one-to-one correspondence with a specific Gx session and PDN connection. This segmentation preserves the association information between sessions while keeping signaling overhead manageable through efficient resource allocation
Solution Approach 2:
The patent introduces a new dimension of session management by creating subsessions within the S9 session hierarchy. This dimensional change allows simultaneous maintenance of multiple associations (home PCRF to visited PCRF, visited PCRF to P-GW, and P-GW to UE) without increasing signaling overhead proportionally
Data Source
AI summary
A method for performing policy and charging control in different roaming scenarios includes: establishing multiple Packet Data Network (PDN) connections to the same Access Point Name (APN), and performing relocation of a Bearer Binding and Event Report Function (BBERF) after establishing multiple PDN connections to the same APN. This method implements the policy and charging control on multiple PDN connections established to one APN in the roaming scenarios of the home routed and local breakout.