Low-Latency UE Handover Using UPF-Anchored Application Context

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Solution Overview

Problem

Wireless communication networks face challenges in efficiently handing over wireless user devices during mobility, leading to unwanted latency for low-latency applications, as existing systems do not optimize the handover process to preserve application performance.

Innovation Solution

The proposed solution involves a coordinated handover process where application servers and user plane functions exchange data efficiently, utilizing network repository functions to maintain application context and ensure seamless transitions across access nodes, thereby optimizing the handover for low-latency applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If wireless user devices remain coupled to their original application server during handover, then application context is preserved, but latency increases due to extended connection paths

Engineering Contradiction:
Improveapplication context preservationVSAvoidhandover latency
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent introduces a user plane function (UPF) as an intermediary element between the wireless access node and the application server. During handover, the UPF temporarily anchors the user plane connection, allowing the wireless device to switch access nodes without extending the connection path to the original application server. This mediator enables context preservation while minimizing latency by decoupling the control plane handover from the user plane connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional handover procedures are used, then wireless connectivity is maintained during mobility, but application performance deteriorates due to added latency

Engineering Contradiction:
Improvewireless connectivity during mobilityVSAvoidapplication session latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the handover process into control plane operations and user plane operations. The control plane handles the handover signaling between access nodes, while the user plane is independently managed through the UPF anchor. This segmentation allows wireless connectivity to be maintained through standard handover procedures while simultaneously optimizing the user data path to avoid latency penalties, thereby preserving application performance during mobility.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If application servers handle all user data processing, then application functionality is complete, but network complexity increases during handover management

Engineering Contradiction:
Improveapplication functionalityVSAvoidnetwork element coordination
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the user plane anchoring function from the application server and places it in a dedicated user plane function (UPF) element. This extraction removes the burden of handover management from the application server, reducing network element coordination complexity. The application server retains its application-specific processing functionality while the UPF handles the low-level user data path management, thereby simplifying the overall network architecture during handover operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4265005B1Wireless communication network handovers of wireless user equipment that execute low-latency applications
Publication Date: 2026.04.08 T MOBILE INNOVATIONS LLC
  • EP4265005B1 patent drawingFigure 1
  • EP4265005B1 patent drawingFigure 2
  • EP4265005B1 patent drawingFigure 3

AI summary

A source Centralized Unit (CU) serves User Equipment (UE) (101) based on UE application context for a low-latency application in the UE (101). In the source CU, a source Application Server (AS) (115) uses a source User Plane Function (UPF) (113) to serve the low-latency application in the UE (101). In response to a handover to a target CU, the source CU indicates the source UPF (113) to the target CU. The target AS (116) in the target CU uses the source UPF ID to retrieve the UE application context for the UE (101) from the source AS (115). In the target CU, a target AS (116) serves the low-latency application based on the retrieved UE (101) application context.