PCF Selection for UE Group PDU Session Coordination

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Solution Overview

Problem

In current mobile network systems, packet data unit (PDU) sessions of different user equipment (UE) are served by different policy control function (PCF) network elements, even for UEs belonging to the same group, leading to a heavy interaction process between these elements during group policy coordination.

Innovation Solution

A method and apparatus for selecting a PCF network element that determines whether to use the same PCF network element for all UEs in a UE group, with the BSF network element assisting in this selection based on the determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different PCF network elements serve PDU sessions of different UEs even within the same UE group, then each UE can have dedicated policy control, but the interaction process between PCF network elements becomes heavy and complex

Engineering Contradiction:

Improvededicated policy controlVSAvoidinteraction process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple PCF network elements into a single shared PCF that serves all UEs in a UE group. The PCF maintains separate policy control capabilities for each UE while consolidating the network element infrastructure, thereby reducing interaction complexity between multiple PCFs while preserving dedicated policy control functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a universal PCF network element that can serve multiple UEs simultaneously within a UE group. This single PCF performs multiple policy control functions for different UEs, eliminating the need for separate dedicated PCFs and reducing the overall interaction process complexity while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If multiple PCF network elements are used for UEs in the same group, then policy control can be distributed, but the coordination overhead and interaction time increase significantly

Engineering Contradiction:

Improvepolicy control distributionVSAvoidcoordination overhead

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

By merging multiple PCF network elements into a single shared PCF, the patent eliminates the coordination overhead between distributed PCFs. The single PCF maintains internal policy control distribution capabilities while removing the inter-PCF communication and coordination time, thus resolving the time loss associated with distributed architecture.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If separate PCF network elements serve each UE, then policy control granularity is maintained, but the number of network elements and system complexity increases

Engineering Contradiction:

Improvepolicy control granularityVSAvoidnumber of network elements

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal PCF network element that can perform policy control for multiple UEs simultaneously. This single multi-functional PCF maintains the same policy control granularity as multiple separate PCFs would provide, while significantly reducing the number of network elements required in the system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12627761B2Methods and devices for policy control function network element selection

Publication Date: 2026.05.12 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

AI summary

A method for selecting a policy control function (PCF) network element is performed by a first PCF network element. The method includes: in response to a received policy association establishment request being related to a packet data unit (PDU) session of a user equipment (UE) within a UE group, determining whether to select a same PCF network element serving each UE in the UE group for the PDU session of the UE; and requesting a binding support function (BSF) network element to select a PCF network element for the PDU session of the UE based on a result of determining whether to select the same PCF network element for the PDU session of the UE.