Multi-Access PDU Session Steering Across 3GPP and Wi-Fi

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing traffic steering and switching between multiple access networks, particularly in 5G networks, due to limitations in protocol data unit (PDU) session management and quality of service (QoS) enforcement across different radio access technologies.

Innovation Solution

Implementing systems and methods for traffic steering and switching between multiple access networks, including configuring wireless transmit/receive units (WTRUs) to establish and manage PDU sessions across 3GPP and non-3GPP networks, utilizing access traffic steering policies based on filters such as S-NSSAI, DNN, and QoS, and employing non-3GPP interworking functions (N3IWF) for reflective QoS enforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traffic steering and switching between multiple access networks is implemented, then network flexibility and service continuity are improved, but system complexity and management overhead increase

Engineering Contradiction:
Improvenetwork flexibilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments traffic management into distinct functional components: access traffic steering policies for routing decisions, QoS rules for quality parameters, and reflective QoS mechanisms for dynamic adaptation. This segmentation allows complex multi-access traffic management to be handled through modular, manageable policy elements that can be independently configured and enforced across different access networks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces network entities such as the Access and Mobility Management Function (AMF) and Non-3GPP Interworking Function (N3IWF) as intermediaries that coordinate traffic steering between 3GPP and non-3GPP access networks. These intermediaries implement policy control and QoS enforcement, simplifying the overall system architecture by centralizing management functions rather than distributing complexity across all network elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multi-access PDU sessions are established, then service continuity and reliability are improved, but protocol complexity and session management overhead increase

Engineering Contradiction:
Improveservice continuityVSAvoidprotocol complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent establishes a universal PDU session framework that can operate across multiple access networks (3GPP and non-3GPP) simultaneously. The same PDU session structure, QoS rules, and policy mechanisms are applied regardless of which access network is used, enabling service continuity while avoiding the need for access-specific protocol variations that would increase complexity.

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

Solution Approach 2:

The patent implements reflective QoS mechanisms where QoS parameters are dynamically adjusted based on feedback from the access network conditions. The network monitors traffic flow characteristics and access network performance, then applies appropriate QoS rules to maintain service continuity. This feedback-driven approach ensures reliability without requiring pre-configured complex protocols for every possible scenario.

Inventive Principle:
Principle #23Feedback

3Productivity

If access traffic steering policies are enforced, then QoS management and traffic optimization are improved, but processing overhead and enforcement complexity increase

Engineering Contradiction:
Improvetraffic optimizationVSAvoidenforcement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where the WTRU (Wireless Transmit/Receive Unit) autonomously applies QoS rules and enforces traffic steering policies based on locally received policy information. The WTRU independently evaluates traffic flows against configured QoS rules and makes routing decisions without requiring continuous network intervention, thereby optimizing traffic while reducing enforcement complexity at network elements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs preliminary configuration of traffic steering policies and QoS rules before actual traffic flow occurs. Network entities pre-establish access traffic steering policies, QoS parameters, and reflective QoS mechanisms based on expected traffic patterns and service requirements. This preliminary action allows the system to handle traffic optimization efficiently during operation without real-time complex decision-making, reducing processing overhead.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3666032B1Traffic steering and switching between multiple access networks
Publication Date: 2026.02.11 INTERDIGITAL PATENT HOLDINGS INC
  • EP3666032B1 patent drawingFigure 1A
  • EP3666032B1 patent drawingFigure 1B
  • EP3666032B1 patent drawingFigure 1C

AI summary

A WTRU may initiate access for a PDU session over multiple access networks. The WTRU may register with two or more access networks. For example, the WTRU may register with a 3GPP access network (e.g., LTE Advanced) and a non-3GPP access network (e.g., Wi-Fi). The WTRU may determine to request a multi-access PDU session for a (e.g., at least one) PDU session. A multi-access PDU session may correspond to a PDU session where the WTRU communicates one or more PDUs associated with the PDU session over the 3GPP access network and one or more PDUs associated with the PDU session over the non-3GPP access network. The WTRU may receive a confirmation message indicating that a multi-access PDU session has been established. The WTRU may send uplink data over the 3GPP access network and the non-3GPP access network, e.g., in accordance with the established multi-access PDU session.