PDU Session Management for 4G to 5G Network Interworking

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Solution Overview

Problem

Existing mobile communication systems face challenges in providing seamless IP connectivity between 4G and 5G networks, especially for terminals capable of using both technologies.

Innovation Solution

A method and apparatus for interworking between 4G and 5G networks, involving a negotiation procedure between the terminal and the network to determine supportable communication networks, and allocating a single IP address for continuous IP connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a terminal switches between 4G and 5G networks, then network compatibility and service continuity are improved, but IP address allocation complexity increases

Engineering Contradiction:
Improvenetwork compatibilityVSAvoidIP address allocation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the IP address allocation process by introducing a dedicated PDU session management component that handles IP allocation independently from the network switching logic. This separates the complexity of IP address management from the overall network compatibility mechanism, allowing the terminal to switch between 4G and 5G networks while a specialized component manages the IP address allocation and maintenance separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a PDU session as an intermediary layer between the terminal and the network core. This PDU session maintains the IP address allocation context and acts as a mediator that ensures continuous IP connectivity when switching between 4G and 5G networks, reducing the complexity at the terminal by abstracting the IP management details.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If separate IP addresses are allocated for 4G and 5G networks, then network-specific optimization is improved, but service continuity deteriorates

Engineering Contradiction:
Improvenetwork-specific optimizationVSAvoidservice continuity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent implements a universal PDU session framework that can operate across both 4G and 5G networks. The PDU session is designed to be network-agnostic, maintaining the same IP address allocation mechanism whether the terminal is connected to 4G or 5G, thereby ensuring service continuity while still allowing network-specific optimizations through the underlying network infrastructure.

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

Solution Approach 2:

The patent ensures continuous IP address allocation by maintaining the PDU session context across network switches. When a terminal transitions between 4G and 5G, the PDU session persists and continues to manage the IP address without interruption, ensuring that the useful action of IP connectivity remains continuous rather than being reset with each network switch.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If multiple PDU sessions are established for different networks, then network-specific service quality is improved, but system complexity increases

Engineering Contradiction:
Improvenetwork-specific service qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic PDU session management approach where the number and configuration of PDU sessions are adjusted based on the current network state and service requirements. Rather than establishing fixed multiple sessions for all networks, the system dynamically creates or reuses PDU sessions as needed, reducing system complexity while maintaining network-specific service quality when required.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3516904B1Method and apparatus for connecting a terminal to network based on applicable network information in mobile communication system
Publication Date: 2025.05.28 SAMSUNG ELECTRONICS CO LTD
  • EP3516904B1 patent drawingFigure 1
  • EP3516904B1 patent drawingFigure 2
  • EP3516904B1 patent drawingFigure 3~4

AI summary

A communication technology for converging a 5th-generation (5G) communication system for supporting a higher data rate after a 4th-generation (4G) system to an Internet of things (IoT) technology and a system thereof are provided. A method for connecting to a network by a terminal in a mobile communication system wherein a first communication network and a second communication network are operable, and an apparatus thereof are provided. The method includes transmitting, to a mobility management function, information on supportable communication network for the terminal and an attach request message including a packet data unit (PDU) session request, receiving an internet protocol (IP) address allocated based on the information on supportable communication network and an attach accept message including a PDU session response, and connecting to a network based on the IP address.