5G Handover Method for Separated Control and User Planes

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Solution Overview

Problem

Current 5G network architectures lack a handover method that effectively separates the control plane (CP) from the user plane (UP) and mobility management (MM) from session management (SM), leading to inefficiencies in network handover processes.

Innovation Solution

A handover method and apparatus that involves determining by a mobility management network element to hand over a session management SM for user equipment (UE), selecting a target session management SM network element, and triggering the setup of a channel by the target SM network element, including a user plane data channel between a target user plane function entity and a target base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the control plane (CP) and user plane (UP) are separated in the 5G network architecture, then network flexibility and service adaptability are improved, but the complexity of network management and handover procedures increases

Engineering Contradiction:
Improvenetwork flexibilityVSAvoidhandover procedure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the handover procedure into distinct phases: control plane handover (CPHO) for signaling and user plane handover (UPHO) for data transmission. The mobility management network element (MM) handles CPHO by selecting target SM and establishing control channels, while the session management network element (SM) handles UPHO by setting up user plane channels between UPF and RAN. This segmentation allows independent optimization of each plane's handover process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a mobility management network element (MM) as an intermediary that coordinates between the separated control plane and user plane during handover. The MM selects the target session management network element and triggers the channel setup process, acting as a mediator that manages the complexity of coordinated handover between CP and UP without requiring direct interaction between all network elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If mobility management (MM) and session management (SM) are separated in the control plane, then functional modularity and network efficiency are improved, but the coordination overhead and signaling complexity increase

Engineering Contradiction:
Improvenetwork efficiencyVSAvoidsignaling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides control plane functions into mobility management (MM) and session management (SM) as separate network elements. MM handles mobility-related signaling including UE location tracking and handover coordination, while SM handles session-related functions including user plane channel setup and PDU session management. This functional segmentation improves network efficiency by allowing specialized processing in each element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where the MM monitors handover conditions and triggers target SM selection based on UE mobility status. The target SM receives feedback from MM about the handover event and responds by setting up appropriate user plane channels. This feedback loop enables automated coordination between MM and SM, reducing manual configuration complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3468253B1Switching method and device
Publication Date: 2021.04.14 HUAWEI TECH CO LTD
  • EP3468253B1 patent drawingFigure 1
  • EP3468253B1 patent drawingFigure 2
  • EP3468253B1 patent drawingFigure 3

AI summary

This application provides a handover method, including: determining, by a mobility management network element, to hand over a session management SM for user equipment UE, and selecting target session management SM network element; and triggering, by the mobility management network element, a process of setting up a channel by the target SM network element, where the channel includes a user plane data channel between a target user plane function entity and a target base station. Therefore, it is possible to hand over a network in which a CP is separated from a UP and an MM and an SM in the CP are separated from each other.