Mobile Terminal PLMN Search Optimization for Roaming
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Solution Overview
Problem
Mobile terminals face inefficiencies in searching for a Public Land Mobile Network (PLMN) during roaming, leading to increased battery consumption and potential service disconnection due to lengthy network searching processes.
Innovation Solution
A method for a mobile terminal to quickly search for a PLMN by using a fixed list of Mobile Country Code (MCC) and Mobile Network Code (MNC) information, prioritizing the strongest signal strength and pre-approved networks, and automatically registering preferred PLMNs to reduce searching time and battery consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile terminal performs sequential PLMN searching by acquiring PLMN identification information for all received frequencies, then the terminal can find an available PLMN for registration, but the searching process becomes time-consuming and increases battery current consumption
Solution Approach 1:
The terminal stores preferred PLMN information in advance in a preferred PLMN list before actual roaming occurs. When roaming is needed, the terminal retrieves and searches only these pre-stored preferred PLMNs rather than sequentially checking all possible frequencies, thereby reducing searching time while maintaining reliable registration to available networks
Solution Approach 2:
The terminal applies different search strategies for different PLMN types: it prioritizes searching preferred PLMNs (with higher search priority) before searching other available PLMNs. This local differentiation of search quality based on PLMN importance reduces overall searching time while ensuring reliable connection to preferred networks first
2Reliability
If the mobile terminal performs sequential PLMN searching to ensure finding an available network, then roaming service reliability is maintained, but battery current consumption increases
Solution Approach 1:
The terminal pre-stores preferred PLMN information in a preferred PLMN list before roaming occurs. During actual roaming, the terminal searches only these pre-identified preferred PLMNs rather than sequentially scanning all frequencies, significantly reducing battery consumption while maintaining reliable roaming service through pre-selected network options
Solution Approach 2:
The terminal performs partial PLMN searching by focusing only on preferred PLMNs stored in advance, rather than exhaustively searching all possible networks. This partial action approach reduces battery consumption while still ensuring reliable roaming by prioritizing the most suitable pre-identified networks
3Reliability
If the mobile terminal extends PLMN searching period to find suitable network, then service connection reliability improves, but mobile communication service disconnection time increases
Solution Approach 1:
The terminal stores preferred PLMN information in advance and retrieves it when roaming is needed. By searching only these pre-identified preferred PLMNs rather than extending the search period through exhaustive frequency scanning, the terminal achieves reliable service connection while reducing disconnection time caused by prolonged network searching
4Use of energy by moving object
If the mobile terminal uses a shorter PLMN searching period to reduce battery consumption, then energy efficiency improves, but the terminal may miss suitable roaming networks
Solution Approach 1:
The terminal pre-identifies and stores preferred PLMN information before roaming occurs. When actual network selection is needed, the terminal searches only these pre-selected preferred PLMNs, achieving both low battery consumption (by limiting search scope) and high network selection accuracy (by focusing on pre-validated preferred networks)
Solution Approach 2:
The terminal uses feedback information about preferred PLMNs (stored from previous successful registrations or network preferences) to guide the search process. This feedback mechanism ensures accurate network selection by prioritizing networks with proven reliability, while limiting search duration to reduce battery consumption
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
A mobile terminal and a network access method for a mobile terminal roaming service are disclosed. The mobile terminal according to the present invention comprises a control unit for: identifying a roaming area/country corresponding to a current location of a terminal body, on the basis of information included in PLMNs searched for in the terminal body, in response to the detection of a total failure in searching of the terminal body, a wireless communication unit, a lastly registered PLMN, a home PLMN, and PLMNs stored in a SIM; and controlling the wireless communication unit so as to connect to one of PLMNs having been successfully camped in the identified roaming area/country.