PCRF Trigger Mechanism for IP Flow Migration Control

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Solution Overview

Problem

Existing IP flow mobility methods cannot determine whether to delete an access network from a multi-access IP-CAN session when network policies or user equipment subscriptions change, leading to inability to cancel IP flow mobility in such scenarios.

Innovation Solution

An IP flow mobility method and system where a PCRF entity acquires trigger information on network policy or subscription changes and sends indication information to a PCEF entity to delete an access network from the multi-access IP-CAN session, ensuring that the PCEF initiates the deletion process, including options for migrating service data flows to remaining access networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the PCRF entity does not monitor network policy or subscription changes, then the system maintains simplicity in policy management, but the system cannot determine when to delete access networks from multi-access IP-CAN sessions

Engineering Contradiction:
Improveability to determine access network deletionVSAvoidpolicy monitoring mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The PCRF entity is configured to proactively acquire trigger information about network policy changes and UE subscription changes before access network deletion is needed. This preliminary monitoring enables the system to detect conditions that require access network deletion, resolving the contradiction by establishing a proactive detection mechanism rather than reactive response

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the system maintains multi-access IP-CAN sessions without deletion capability, then service continuity is preserved, but the system cannot adapt to network policy or subscription changes

Engineering Contradiction:
Improveresponse to policy changesVSAvoidservice continuity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system implements a feedback mechanism where the PCRF entity continuously monitors trigger information related to network policy changes and subscription changes. When specific trigger conditions are met, the system sends indication information to the PCEF entity to delete access networks from multi-access IP-CAN sessions. This feedback loop ensures the system adapts to changes while maintaining service continuity through controlled transitions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the composition of multi-access IP-CAN sessions based on real-time network conditions, policy changes, and subscription information. The access network configuration is not static but can be modified by deleting specific access networks when trigger conditions are met, enabling the system to balance adaptability with service continuity

Inventive Principle:
Principle #15Dynamics

3Speed

If the PCEF entity automatically deletes access networks upon policy changes, then system responsiveness is improved, but uncontrolled deletions may occur without proper trigger verification

Engineering Contradiction:
Improveresponse speed to policy changesVSAvoidcontrolled deletion
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The PCRF entity performs preliminary verification of trigger information before initiating access network deletion. It acquires and evaluates trigger information related to network policy changes and subscription changes, ensuring that deletion only occurs when verified trigger conditions are met. This preliminary action prevents uncontrolled deletions while maintaining rapid response through the subsequent indication mechanism to the PCEF entity

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3404884B1IP flow migration method, device and system
Publication Date: 2021.08.04 ZTE CORP
  • EP3404884B1 patent drawingFigure 1~3
  • EP3404884B1 patent drawingFigure 4~5
  • EP3404884B1 patent drawingFigure 6~8

AI summary

Disclosed in the present invention are an IP flow migration method, device and system. The method comprises: a policy and charging rule function (PCRF) entity obtaining trigger information, the trigger information comprising deleting information of an access network from a multi-access IP-CAN session; the PCRF entity determining whether to send instruction information to a policy and charging execution function (PCEF) entity according to the trigger information, the instruction information comprising instructing the PCEF entity to delete an access network from the multi-access IP-CAN session, such that the PCEF entity initiates a process of deleting an access network from the multi-access IP-CAN session. Thus, when a network policy is changed, or when a UE contract is changed, an access network may be deleted from the multi-access IP-CAN session. Therefore, the problem in which IP flow migration cannot be canceled when a network policy is changed, or when a UE contract is changed, can be prevented.