SMF Relocation via Branching Point for 5G Session Continuity

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Solution Overview

Problem

In 5G mobile communications, ensuring seamless session continuity when user equipment moves between different service areas, as existing technologies face challenges in managing session management function (SMF) network element relocation without interrupting user plane connections.

Innovation Solution

The method involves the SMF network element receiving identification information from the access and mobility management function (AMF) network element, obtaining information about anchor user plane function (UPF) network elements, and sending this information to a branching point to establish user plane connections across areas, ensuring continuous session management during equipment movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SMF network element relocation is performed when user equipment moves between service areas, then session continuity is maintained, but network element management complexity increases

Engineering Contradiction:
Improvesession continuityVSAvoidnetwork element management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the SMF management function by introducing a branching point that separates the anchor UPF management from the local UPF management. This allows the first SMF to manage only the anchor UPF while the branching point manages local UPFs, reducing the management complexity of individual SMF network elements while maintaining session continuity during relocation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a branching point as an intermediary between the SMF network elements and UPF network elements. This branching point acts as a mediator that receives traffic from the anchor UPF and distributes it to appropriate local UPFs, simplifying the management architecture during SMF relocation while ensuring uninterrupted user plane connections.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple anchor UPF network elements are managed by different SMF network elements, then service area flexibility is improved, but information management complexity increases

Engineering Contradiction:
Improveservice area flexibilityVSAvoidinformation management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the first SMF obtain information about multiple anchor UPF network elements before SMF relocation occurs. The first SMF proactively acquires and stores the information about anchor UPFs managed by different SMFs, which enables seamless session continuity when relocation happens, as the branching point already has the necessary information to establish connections with the appropriate anchor UPFs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The first SMF network element is designed with multi-functionality, serving both as a session management function for the user equipment and as an information collection point for anchor UPF details. This universal role allows the first SMF to manage service area flexibility by maintaining information about multiple anchor UPFs across different service areas without requiring separate specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If user plane connections are established across multiple areas, then session continuity is ensured, but connection establishment complexity increases

Engineering Contradiction:
Improvesession continuityVSAvoidconnection establishment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling the branching point to autonomously establish user plane connections with anchor UPF network elements. The branching point receives information about anchor UPFs from the first SMF and independently sets up the necessary user plane connections without requiring manual intervention or complex coordination protocols, thereby ensuring session continuity while reducing connection establishment complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3764620B1Redirection method and device
Publication Date: 2024.06.12 HUAWEI TECH CO LTD
  • EP3764620B1 patent drawingFigure 1~2
  • EP3764620B1 patent drawingFigure 3~4
  • EP3764620B1 patent drawingFigure 5

AI summary

This application relates to the field of wireless communications technologies, and provides a relocation method, including: receiving, by a first session management function network element, first identification information from an access and mobility management function network element; obtaining information about a plurality of anchor user plane function network elements of a first session based on the first identification information; and sending, by the first session management function network element, the information about the plurality of anchor user plane function network elements to a branching point, where the branching point is a user plane function network element that is managed by the first session management function network element and that has a function of diverting traffic . According to the solutions provided in the embodiments, when user equipment establishes the first session in a first area, then moves to a second area, and continues to move to another area from the second area, session management function network element is redirected, to ensure that the first session is not interrupted. This improves user experience.