PLMN Selection in Roaming Terminals via Active List

Solution Overview

Problem

Existing PLMN selection methods in portable terminals lead to increased battery consumption and unnecessary time consumption when attempting registration in non-existent Home PLMNs during roaming, as they sequentially try to register with PLMNs without a valid Active PLMN list.

Innovation Solution

A method and apparatus for a portable terminal to determine the validity of the registered PLMN, check for an Active PLMN list, and select a PLMN from this list for registration, thereby avoiding attempts to register with non-existent Home PLMNs and reducing battery consumption by efficiently selecting a suitable PLMN.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the portable terminal sequentially attempts registration with PLMNs according to the preferred PLMN list when the RPLMN is invalid, then the terminal can eventually find a suitable PLMN, but this results in increased battery consumption and time consumption

Engineering Contradiction:

ImprovePLMN selection reliabilityVSAvoidPLMN selection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The terminal performs preliminary actions by checking for the existence of HPLMN/EHPLMN before attempting sequential PLMN selection. When in roaming state, the terminal proactively determines that HPLMN does not exist and skips the sequential selection process, directly selecting from available PLMNs. This preliminary check prevents unnecessary time consumption and battery drain from attempting registration with non-existent networks.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention dynamically adjusts the PLMN selection strategy based on the terminal's roaming state. When roaming is detected, the system changes its behavior from sequential PLMN attempt (which would include non-existent HPLMN) to direct selection from available PLMNs. This dynamic adaptation optimizes both time and energy efficiency while maintaining reliable network connection.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the portable terminal attempts registration with HPLMN when in roaming state, then the terminal follows the standard PLMN selection procedure, but this causes unnecessary battery consumption since HPLMN does not exist in the real field

Engineering Contradiction:

ImprovePLMN selection procedure standardizationVSAvoidbattery consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The terminal performs a preliminary check to determine whether it is in a roaming state before executing the standard PLMN selection procedure. By detecting the roaming state in advance, the terminal can modify its selection process to skip HPLMN attempts, thereby preventing unnecessary battery consumption while still maintaining a systematic and organized selection approach.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention applies different selection strategies to different operational contexts: when not roaming, the terminal follows the standard procedure including HPLMN attempts; when roaming, it switches to a localized strategy that excludes HPLMN and directly selects from available PLMNs. This context-specific adaptation optimizes energy usage while preserving procedural integrity.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the portable terminal sequentially selects PLMNs one by one when priority does not exist or PLMNs have the same priority, then the terminal can find a suitable network, but this results in unnecessary time consumption and battery consumption

Engineering Contradiction:

ImprovePLMN selection flexibilityVSAvoidPLMN selection efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The terminal performs preliminary actions by checking for the existence of HPLMN/EHPLMN before attempting sequential PLMN selection. When in roaming state, the terminal proactively determines that HPLMN does not exist and skips the sequential selection process, directly selecting from available PLMNs. This preliminary check prevents unnecessary time consumption and battery drain from attempting registration with non-existent networks.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention dynamically adjusts the PLMN selection strategy based on the terminal's roaming state. When roaming is detected, the system changes its behavior from sequential PLMN attempt (which would include non-existent HPLMN) to direct selection from available PLMNs. This dynamic adaptation optimizes both time and energy efficiency while maintaining reliable network connection.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9031555B2PLMN selection method and apparatus in portable terminal

Publication Date: 2015.05.12 SAMSUNG ELECTRONICS CO LTD

AI summary

A Public Land Mobile Network (PLMN) selection method in a roaming portable terminal and an apparatus thereof are provided. The PLMN selection method includes, determining whether a registered PLMN being a finally registered PLMN is valid when a PLMN selection event occurs, determining whether there is a stored Active PLMN list when the registered PLMN is invalid, selecting a PLMN using the active PLMN list when there is the stored Active PLMN list, and camping on a specific cell of the selected PLMN. Since the portable terminal does not attempt to register in an HPLMN when a PLMN selection event occurs, the portable terminal can be rapidly and efficiently registered in a suitable PLMN.