UE Timer T3245 IMSI Match Control

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Solution Overview

Problem

In user equipment (UE), the timer T3245 is not effectively managed when the SIM changes, leading to incorrect behavior and unnecessary registration attempts with forbidden PLMNs, causing delays in camping and registration with the network, resulting in extended out-of-service periods and missed calls or services.

Innovation Solution

A method is implemented where a controller in the UE determines whether the current IMSI matches the stored IMSI upon power-on, and if not, stops the timer T3245, ensuring accurate management of the timer based on SIM changes, thereby preventing unnecessary registration attempts with forbidden PLMNs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the timer T3245 is restarted with a random value after SIM change, then the timer management becomes simpler, but the UE performs unnecessary registration attempts with forbidden PLMNs causing delays in camping and registration

Engineering Contradiction:

Improvetimer management complexityVSAvoidcamping and registration delay

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by checking whether the current IMSI matches the stored IMSI before restarting the timer T3245. This pre-check prevents unnecessary timer restarts when SIM cards are swapped, thereby avoiding unwanted registration attempts with forbidden PLMNs and reducing camping delays without adding significant complexity to the timer management logic.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the UE checks remaining time period and removes forbidden PLMN list after timer expiration, then the PLMN access restriction is automatically lifted, but the UE attempts registration with forbidden PLMNs when SIM changes occur

Engineering Contradiction:

ImprovePLMN access control reliabilityVSAvoidregistration attempt behavior

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements feedback by continuously monitoring IMSI changes and using this information to control timer T3245 behavior. When SIM cards are swapped (IMSI changes), the timer is not restarted, providing feedback-based control that prevents the UE from attempting registration with forbidden PLMNs. This maintains reliable PLMN access control while ensuring appropriate registration behavior after SIM changes.

Inventive Principle:

Principle #23Feedback

3Device complexity

If the timer T3245 is not managed based on SIM changes, then the timer operation is simpler, but the UE experiences extended out-of-service periods and missed calls or services

Engineering Contradiction:

Improvetimer control logic complexityVSAvoidservice recovery speed

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent applies preliminary action by implementing an IMSI change detection mechanism that proactively controls timer T3245 behavior before service degradation occurs. When SIM changes are detected, the timer management is adjusted accordingly, preventing extended out-of-service periods and missed calls while maintaining relatively simple timer control logic through a straightforward IMSI comparison approach.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9936386B2Method of controlling a timer in user equipment

Publication Date: 2018.04.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of controlling a timer in a User Equipment (UE) is provided. The method includes determining, by a controller in the UE, whether a current international mobile subscriber identity (IMSI) matches a stored IMSI if the UE is powered ON, activating, by the controller, the timer if the current IMSI matches the stored IMSI; and stopping the timer if the current IMSI does not match the stored IMSI.