User Equipment Roaming Between 3GPP and Non-3GPP Networks

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Solution Overview

Problem

Conventional methods for User Equipment (UE) transitioning between a roaming 3GPP network and a non-3GPP network, such as from LTE to Wi-Fi or vice versa, result in service unavailability due to a 'break-before-make' procedure, which worsens user experience.

Innovation Solution

The UE maintains a connection over one network while performing an initial attach procedure over the other network, allowing continuous service and incoming call handling during the transition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE releases the connection over the roaming 3GPP network before performing initial attach procedure to establish a new connection over the non-3GPP network, then the network connection can be re-established, but service unavailability occurs during the transition period

Engineering Contradiction:

Improveconnection reliabilityVSAvoidservice unavailability time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The UE performs preliminary actions by keeping the existing connection alive and preparing the new attach procedure in advance. The UE maintains the PDP context and connection state while initiating the new attach procedure, so that when the new connection is established, service can continue without interruption. This preliminary preparation eliminates the need to release the old connection before establishing the new one.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements continuity of useful action by maintaining the existing PDP context and connection state during the transition. The UE keeps the bearing open and preserves connection state information, allowing data sessions to continue uninterrupted. The useful action of data transmission remains continuous while the network reconfiguration happens in the background.

Inventive Principle:

Principle #20Continuity of useful action

2Productivity

If the UE keeps the connection over one network during initial attach procedure over the other network, then continuous service is maintained, but network complexity increases

Engineering Contradiction:

Improveservice continuityVSAvoidnetwork connection management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the connection management into distinct components: the existing PDP context is segmented from the new attach procedure. The UE maintains the old connection's PDP context separately while initiating a new attach procedure. This segmentation allows independent management of both connections, reducing the complexity of coordinating them simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism through the use of PDP context preservation and connection state maintenance. These intermediary structures act as buffers that bridge the old and new connections, allowing seamless transition. The intermediary PDP context serves as a mediator that enables both connections to coexist and work together during the transition period.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the UE performs break-before-make procedure for network switching, then the new connection can be established, but user experience deteriorates due to service disruption

Engineering Contradiction:

Improveconnection establishmentVSAvoiduser experience

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent inverts the conventional break-before-make approach by implementing make-before-break. Instead of releasing the old connection before establishing the new one, the UE establishes the new connection while keeping the old one active. This inversion of the procedural sequence eliminates the service disruption that plagues the traditional approach and significantly improves user experience during network switching.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11528592B2Apparatuses and methods for robust moving between a roaming 3GPP network and a non-3GPP network

Publication Date: 2022.12.13 MEDIATEK INC

AI summary

A method for robust moving between a roaming Third Generation Partnership Project (3GPP) network and a non-3GPP network is provided. The method includes the steps of: connecting with a home 3GPP network over one of a roaming 3GPP network and a non-3GPP network by a User Equipment (UE); performing a first initial attach procedure with the home 3GPP network over the other of the roaming 3GPP network and the non-3GPP network by the UE in response to the UE moving from the one of the roaming 3GPP network and the non-3GPP network to the other of the roaming 3GPP network and the non-3GPP network; and keeping the connection over the one of the roaming 3GPP network and the non-3GPP network by the UE during the first initial attach procedure over the other of the roaming 3GPP network and the non-3GPP network.