Mobile Device Equivalent PLMN List Management

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Mobile communication devices may select forbidden PLMNs for PLMN selection procedures after restarting due to the failure to remove forbidden PLMNs from the Equivalent PLMN List during emergency bearer services, leading to delayed access to normal services.

Innovation Solution

The mobile communication device removes forbidden PLMNs from the Equivalent PLMN List before power-off and stores the updated lists, ensuring that only non-forbidden PLMNs are included in the Equivalent PLMN List for subsequent PLMN selection procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the UE saves the Equivalent PLMN List obtained during emergency bearer services, then the PLMN selection procedures can be performed after restart, but the UE may select forbidden PLMNs leading to delayed access to normal services

Engineering Contradiction:
ImprovePLMN selection procedureVSAvoidservice acquisition time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The UE performs preliminary action by removing forbidden PLMNs from the Equivalent PLMN List before power-off. This preparatory step ensures that when the UE restarts and needs to perform PLMN selection procedures, only non-forbidden PLMNs are available, preventing selection of forbidden networks and reducing service acquisition time.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the UE removes forbidden PLMNs from the Equivalent PLMN List before power-off, then forbidden PLMNs are not selected after restart, but additional processing time is required during power-off

Engineering Contradiction:
ImprovePLMN selection accuracyVSAvoidpower-off processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The UE performs the removal of forbidden PLMNs as a preliminary action before power-off. Although this requires additional processing time during power-off, it ensures reliability by preventing selection of forbidden PLMNs after restart. The processing time is incurred once during power-off, avoiding repeated issues during subsequent PLMN selection procedures.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2437550B1Apparatus and method for handling of an equivalent public land mobile network (PLMN) list
Publication Date: 2015.01.21 HTC CORP
  • EP2437550B1 patent drawingFigure 1
  • EP2437550B1 patent drawingFigure 2
  • EP2437550B1 patent drawingFigure 3

AI summary

A mobile communication device (110) with a wireless module (111) and a controller module (112) is provided. The wireless module (111) performs wireless transmissions and receptions to and from a service network (120,130). The controller module (112) obtains a list (S810) of Public Land Mobile Networks PLMNs equivalent to each other when attached to the service network for emergency bearer services via the wireless module, and not stores the list in response to a power-off of the mobile communication device (110).