ProSe Function VPLMN ID Update for D2D Roaming

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Solution Overview

Problem

In LTE wireless communication systems, when a user equipment (UE) is roaming and changes serving public land mobile networks (PLMNs), the visited PLMN ID stored in the home PLMN's ProSe function becomes outdated, leading to incorrect notifications and communication disruptions.

Innovation Solution

A method where the ProSe function in the home PLMN of an announcing UE receives a match report message with a ProSe Application Code from a monitoring UE and responds with a match response message containing the current PLMN ID of the visited PLMN, ensuring accurate communication and avoiding outdated PLMN ID issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ProSe function stores the VPLMN ID of the announcing UE in the home PLMN, then the monitoring function can operate, but the stored VPLMN ID becomes outdated when the announcing UE changes serving PLMN

Engineering Contradiction:

Improveaccuracy of VPLMN IDVSAvoidtime delay in updating VPLMN ID

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the ProSe function in the home PLMN receives match report messages from monitoring UEs and responds with match response messages that contain updated VPLMN ID information. This feedback loop ensures that the VPLMN ID is continuously updated based on current network conditions rather than relying on stale stored information.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary actions by including the current VPLMN ID in the match response message before the monitoring function needs to use it for notifications. This proactive approach ensures that the VPLMN ID is updated and available before any potential communication errors can occur.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the ProSe function uses the stored VPLMN ID for notifications, then the notification process is simple, but notifications are sent to wrong ProSe functions in different VPLMNs

Engineering Contradiction:

Improvesimplicity of notification processVSAvoidaccuracy of notification routing

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The notification routing is improved by implementing a feedback mechanism where the match response message contains the current VPLMN ID that is used to route notifications correctly. This ensures that while the notification process remains simple, the routing accuracy is maintained through continuous updates of the VPLMN ID information.

Inventive Principle:

Principle #23Feedback

3Reliability

If the ProSe function updates the VPLMN ID frequently to maintain accuracy, then communication reliability improves, but system complexity increases

Engineering Contradiction:

Improveaccuracy of VPLMN IDVSAvoidcomplexity of VPLMN ID management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent reduces system complexity by performing preliminary actions where the VPLMN ID is updated in advance and included in the match response message. This eliminates the need for complex real-time update mechanisms and frequent synchronization protocols, while still maintaining high reliability of VPLMN ID information.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2963897B1Method of identifying visited public land mobile network and related communication device in d2d communications

Publication Date: 2017.12.20 HTC CORP

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AI summary

A method of identifying a visited public land mobile network (VPLMN)comprises a proximity service (ProSe) function in a home PLMN (HPLMN) of an announcing user equipment (UE) receiving a match report message comprising a ProSe Application Code from a ProSe function in a HPLMN of a monitoring UE; and the ProSe function in the HPLMN of the announcing UE transmitting a match response message comprising a ProSe Application ID Name of the ProSe Application Code and a PLMN ID of a VPLMN registered by the announcing UE to the ProSe function in the HPLMN of the monitoring UE to respond to the match report message.