MA PDU Session Control Across PLMNs for HPLMN Traffic Steering

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Solution Overview

Problem

Existing 5G communication systems fail to support Multi-Access Protocol Data Unit (MA PDU) session establishment when user equipment (UE) is registered on different Public Land Mobile Networks (PLMNs, leading to terminated sessions and high roaming charges for the home operator.

Innovation Solution

Implement a method and system for Home Public Land Mobile Network (HPLMN)-based traffic control by establishing a MA PDU session with UE registered on different PLMNs, using an HPLMN to determine and enforce an Access Traffic Steering, Switching, and Splitting (ATSSS) policy, ensuring the UE receives an ATSSS policy message.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE establishes separate PDU sessions with each PLMN when registered on multiple PLMNs, then each PLMN can independently manage its own traffic, but the signaling overhead increases and session management becomes complex

Engineering Contradiction:

ImprovePLMN-specific traffic managementVSAvoidsession management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple PLMN-specific PDU sessions into a single MA PDU session that carries traffic from multiple PLMNs simultaneously. The network node establishes one MA PDU session between the UE and the data network, which then handles traffic from multiple PLMNs through a unified interface, reducing the number of separate sessions needed.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary network node (such as a UPF or network exposure function) that acts as a mediator between multiple PLMNs and the data network. This intermediary receives traffic from multiple PLMNs, performs policy control and routing, and forwards it through a single MA PDU session, simplifying session management while maintaining PLMN-specific traffic handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the UE establishes separate PDU sessions with each PLMN when registered on multiple PLMNs, then each PLMN can independently manage its own traffic, but the signaling overhead increases

Engineering Contradiction:

ImprovePLMN-specific traffic managementVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent combines multiple PLMN-specific PDU sessions into a single MA PDU session, which consolidates the signaling required for session management. Instead of establishing and maintaining separate PDU sessions for each PLMN, the network uses one unified session that carries traffic from multiple PLMNs, thereby reducing signaling overhead.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The MA PDU session is designed with multi-functionality to handle traffic from multiple PLMNs simultaneously. A single session structure supports multiple PLMN identities and traffic flows, making the session management system universal rather than requiring separate specialized sessions for each PLMN.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If a single MA PDU session is established for multiple PLMNs, then signaling overhead is reduced, but traffic differentiation and policy control between PLMNs becomes more difficult

Engineering Contradiction:

Improvesession establishment efficiencyVSAvoidtraffic differentiation difficulty

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies local quality by maintaining PLMN-specific characteristics within the unified MA PDU session. The network node identifies and separates traffic from different PLMNs using PLMN-specific identifiers and applies PLMN-specific policies, QoS parameters, and routing rules to each traffic flow, ensuring that each PLMN's traffic is handled with appropriate local quality control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements feedback mechanisms where the network node continuously monitors traffic flows within the MA PDU session, identifies the source PLMN, and adjusts policy control and routing decisions based on PLMN-specific requirements. This feedback loop enables the system to maintain traffic differentiation and policy control despite using a unified session structure.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4447409B1Method and system for hplmn-based traffic control when UE is registered on different plmns

Publication Date: 2026.05.13 SAMSUNG ELECTRONICS CO LTD

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AI summary

The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Embodiments herein provide a method for establishing a multi-access protocol data unit (MA PDU) session of a user equipment (UE) by a home public land mobile network (HPLMN) in a wireless communication network.