Application Function UE IP Preservation for Efficient UP Path Routing

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Solution Overview

Problem

In wireless communications networks, the independent management of Protocol Data Unit (PDU) sessions by multiple Session Management Functions (SMFs) leads to inefficient end-to-end User Plane (UP) paths, particularly in scenarios involving IP Multimedia Subsystem (IMS) communications, resulting in poor QoS provisioning, inefficient routing, and increased mobility management overhead.

Innovation Solution

Implementing a method where an Application Function (AF) influences traffic routing by sending requests to a Policy Control Function (PCF) to manage UE IP addresses, ensuring that UE IP addresses are preserved and UP paths are correlated, thereby preventing unnecessary reselection of PDU session anchors (PSAs) and optimizing UP paths for groups of User Equipment (UEs).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If individual PDU sessions are managed independently by multiple SMFs, then each SMF can manage its session autonomously, but the end-to-end UP path becomes inefficient and QoS provisioning deteriorates

Engineering Contradiction:

Improveautonomous session managementVSAvoidend-to-end UP path efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent merges the management of multiple independent PDU sessions under a single master SMF that can correlate sessions and optimize end-to-end UP paths. The master SMF consolidates control to make coordinated routing decisions across multiple sessions, eliminating the inefficiencies of completely independent management while maintaining the autonomy of individual session configurations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary mechanism where the master SMF acts as a coordinator between multiple SMFs and the UPF. This intermediary role allows the system to maintain autonomous session management at the individual SMF level while enabling centralized optimization of end-to-end paths through the master SMF's correlation and coordination capabilities.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If UP paths are selected independently by different SMFs, then each SMF can make independent routing decisions, but the end-to-end UP path becomes suboptimal

Engineering Contradiction:

Improveindependent routing decision capabilityVSAvoidend-to-end routing efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent combines independent routing decision capabilities with centralized path optimization by having the master SMF aggregate routing information from multiple SMFs and make coordinated UP path selections. This allows the system to maintain the adaptability of independent decision-making while achieving optimal end-to-end routing through consolidated control.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If UE IP address is not preserved during PDU session reselection, then the network can optimize routing dynamically, but application layer connectivity is disrupted

Engineering Contradiction:

Improverouting optimization flexibilityVSAvoidapplication layer connectivity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating between control plane flexibility and user plane stability. The UE IP address is preserved at the application layer to maintain connectivity reliability, while the network simultaneously optimizes routing dynamically through PDU session reselection and UP path modification. This localized differentiation allows both conflicting requirements to be satisfied in their respective domains.

Inventive Principle:

Principle #3Local quality

4Productivity

If PDU session anchors are reselected frequently to optimize paths, then routing efficiency improves, but mobility management overhead increases

Engineering Contradiction:

Improverouting efficiencyVSAvoidmobility management overhead

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the master SMF proactively optimize UP paths before mobility events trigger frequent PSA reselections. By anticipating routing inefficiencies and pre-adjusting paths through coordinated session management, the system reduces the need for reactive PSA reselections, thereby maintaining routing efficiency while minimizing mobility management overhead.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4607857A1Message and system for application function influence on traffic routing

Publication Date: 2025.08.27 HUAWEI TECH CO LTD

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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.