Multi-Access PDU Session Transition Across 5G and EPC

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing mobile communication networks face challenges in efficiently managing and transitioning multi-access protocol data unit (PDU) sessions across different generations and network types, such as between 5G and LTE networks, leading to inefficiencies in session management and continuity.

Innovation Solution

The implementation of methods and systems for managing multi-access PDU sessions, including procedures for establishing, transitioning, and upgrading PDU sessions between 3GPP and non-3GPP access legs, utilizing network entities and wireless transmit/receive units to facilitate seamless connectivity and resource sharing across different wireless technologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-access PDU sessions are managed across different generations and network types, then network versatility and connectivity options are improved, but session management complexity increases

Engineering Contradiction:
Improvenetwork versatilityVSAvoidsession management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the session management function by introducing separate control plane and user plane functions. The control plane handles session establishment and management while the user plane handles data transmission, allowing complex multi-access sessions to be managed through modular, independent components that reduce overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a session management function as an intermediary between the control plane and user plane. This intermediary coordinates the complex interactions between different network types (3GPP and non-3GPP access networks), simplifying the management of multi-access PDU sessions by centralizing control logic.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If seamless transitions between 3GPP and non-3GPP access legs are enabled, then service continuity is improved, but signaling overhead increases

Engineering Contradiction:
Improveservice continuityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by pre-establishing policy rules and routing information in the control plane before actual data transmission occurs. This allows the network to prepare transition paths and routing decisions in advance, reducing real-time signaling overhead during actual service continuity events.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the session management function continuously monitors the state of PDU sessions and adjusts routing decisions accordingly. This feedback loop enables seamless transitions by detecting conditions and initiating appropriate actions without requiring excessive signaling, as the system adapts dynamically based on actual network state.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4104626B1Methods, apparatus and systems for multi-access protocol data unit sessions
Publication Date: 2026.04.15 INTERDIGITAL PATENT HOLDINGS INC
  • EP4104626B1 patent drawingFigure 1A
  • EP4104626B1 patent drawingFigure 1B
  • EP4104626B1 patent drawingFigure 1C

AI summary

A wireless transmit/receive unit (WTRU) may establish a multi-access (MA) protocol data unit (PDU) in accordance with the examples described herein. The WTRU may establish a new packet data network (PDN) connection or identify a suitable existing PDN connection in an evolved packet core (EPC), establish a MA-PDU in a 5G core network (5GC), and associate the existing PDN with the MA-PDU. The WTRU may already have a MA-PDU session established in 5GC with both 3GPP access leg and non- 3GPP access leg in 5GC, and the WTRU may replace the 3GPP access leg in 5GC with a suitable PDN connection in EPC. The WTRU may send a request for establishing a single-access PDU session in 5GC via non-3GPP access, and a 5GC network may upgrade a PDU session established for the WTRU to a MA-PDU with 3GPP access leg in EPC.