PDU Session Correlation for Efficient User Plane Routing

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Solution Overview

Problem

Inefficient end-to-end User Plane (UP) paths in wireless communications networks result from independent management of Protocol Data Unit (PDU) sessions by multiple Session Management Functions (SMFs, leading to poor QoS provisioning, inefficient routing, and increased mobility management overhead, especially in scenarios involving multiple UEs communicating through IMS applications.

Innovation Solution

The system correlates PDU sessions belonging to a group of UEs and optimizes UP paths jointly, allowing for joint UPF and DNAI selection based on AF requests that include information on traffic identification, location, and correlation type, enabling efficient end-to-end routing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple SMFs independently manage PDU sessions, then each session can be managed autonomously, but end-to-end routing efficiency deteriorates and QoS provisioning becomes poor

Engineering Contradiction:
ImproveIndependent PDU session managementVSAvoidEnd-to-end routing efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent introduces a PDU session correlation mechanism that merges the management of multiple independent PDU sessions under a unified correlation context. When the SMF detects correlated PDU sessions (e.g., belonging to the same UE group or application), it establishes correlations between them and performs joint UP path selection, thereby improving end-to-end routing efficiency while preserving the operational autonomy of individual sessions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediate correlation management layer that acts as a mediator between independent SMF operations and coordinated routing decisions. This intermediary mechanism tracks PDU session correlations and enables the SMF to make informed routing decisions that optimize end-to-end paths without compromising the independent management capability of individual sessions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If independent UP path selection is performed by different SMFs, then session management flexibility is maintained, but mobility management overhead increases

Engineering Contradiction:
ImproveSession management flexibilityVSAvoidMobility management overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent merges mobility management operations for correlated PDU sessions by implementing joint UP path selection. When PDU sessions are correlated, the SMF performs coordinated UP path decisions that reduce redundant mobility management signaling and processing, thereby reducing overhead while preserving the flexibility to manage sessions independently when no correlation exists.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If PDU sessions are managed independently, then system complexity is reduced, but QoS provisioning quality deteriorates

Engineering Contradiction:
ImprovePDU session management complexityVSAvoidQoS provisioning quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments QoS provisioning into two levels: individual PDU session management (maintaining low complexity) and correlated session QoS optimization (improving quality). The SMF implements correlation detection and joint UP path selection only for identified correlated sessions, thereby improving QoS provisioning where needed while maintaining simple independent management for uncoded sessions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by implementing correlation-based joint management only for specific PDU sessions that meet correlation criteria, rather than applying complex joint management to all sessions. This selective approach improves QoS provisioning for correlated sessions while avoiding the complexity overhead of universal joint management.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3815306B1Message and system for application function influence on traffic routing
Publication Date: 2026.03.04 HUAWEI TECH CO LTD
  • EP3815306B1 patent drawingFigure 1
  • EP3815306B1 patent drawingFigure 2
  • EP3815306B1 patent drawingFigure 3

AI summary

An aspect of the disclosure provides for a method for user equipment (UE) internet protocol (IP) address management. The method includes sending by an application function (AF), a request to a policy control function (PCF), the request including information identifying traffic and an indication that a UE IP address associated with the traffic should be preserved. The method further includes sending by the PCF, to a session management function (SMF) being responsible for managing a Protocol Data Unit (PDU) session associated with the traffic, a policy and charging control (PCC) rule including the indication. In some embodiments, the request is sent by the AF to the PCF via a network exposure function (NEF). In some embodiments, the method further includes managing, by the SMF, the UE IP address according to the PCC rule. In some embodiments, the managing includes preserving the UE IP address for a PDU session associated with the traffic. In some embodiments, the preserving includes preventing reselection of a protocol data unit (PDU) session anchor (PSA) to which the UE IP address is associated.