PLMN Selector File Optimization for EHPLMN Network Access

Solution Overview

Problem

In wireless communications, user equipment (UE) face inefficiencies in accessing multiple equivalent home public land mobile networks (EHPLMNs) due to searching for radio access technologies (RATs) that may not exist at a particular location, leading to increased time and battery consumption.

Innovation Solution

The UE optimizes PLMN selection by utilizing a customized PLMN selector file within the subscriber identity module (SIM) that associates specific mobile country code/mobile network code (MCC/MNC) data with corresponding RATs, allowing it to search only for relevant RAT-PLMN combinations, reducing unnecessary searches and conserving resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE searches for all RATs for each EHPLMN entry in the order defined within the SIM, then the UE ensures comprehensive network coverage search, but the UE expends excessive time and battery life searching for RATs that do not exist at a particular location

Engineering Contradiction:

Improvenetwork access reliabilityVSAvoidnetwork access time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The network device performs preliminary actions by determining network deployment information in advance and generating a customized PLMN selector file that associates specific RATs with each EHPLMN entry. This file is provided to the UE before the UE performs PLMN selection, allowing the UE to skip searching for RATs that are known not to be deployed at specific locations, thereby reducing network access time while maintaining comprehensive coverage search reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A customized PLMN selector file acts as an intermediary between the network device and the UE. This file contains pre-determined RAT-EHPLMN associations that guide the UE's search process, eliminating the need for the UE to perform exhaustive searches for all RATs at every location while ensuring reliable network access to available networks

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the UE searches for all RATs for each EHPLMN entry in the order defined within the SIM, then the UE ensures comprehensive network coverage search, but the UE consumes excessive battery life

Engineering Contradiction:

Improvenetwork access reliabilityVSAvoidbattery consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The network device performs preliminary actions by determining network deployment information in advance and generating a customized PLMN selector file that associates specific RATs with each EHPLMN entry. This file is provided to the UE before the UE performs PLMN selection, allowing the UE to skip searching for RATs that are known not to be deployed at specific locations, thereby reducing network access time while maintaining comprehensive coverage search reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A customized PLMN selector file acts as an intermediary between the network device and the UE. This file contains pre-determined RAT-EHPLMN associations that guide the UE's search process, eliminating the need for the UE to perform exhaustive searches for all RATs at every location while ensuring reliable network access to available networks

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If the UE searches for RATs that do not exist at a particular location, then the UE maintains a standardized search procedure across all locations, but the UE performs unnecessary searches wasting time and resources

Engineering Contradiction:

Improvesearch procedure standardizationVSAvoidnetwork selection efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The solution implements local quality by providing location-specific RAT information through the customized PLMN selector file. Each EHPLMN entry is associated with specific RATs that are actually deployed at that location, allowing the UE to perform standardized search procedures while adapting to local network conditions, thereby eliminating unnecessary searches and improving network selection efficiency

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11089534B2Optimization of access technology search in multiple equivalent home public land mobile network (EHPLMN) deployments

Publication Date: 2021.08.10 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Communication systems can enhance customer experience by quickly and efficiently associating and disassociating radio access technologies (RATs) from available networks in a deployment. In one aspect, a user equipment (UE) can optimize usage of a PLMN selector file (e.g., HPLMNwACT) stored within the subscriber identity module (SIM) that comprises a combination of mobile country code/mobile network code (MCC/MNC) data and RAT data (e.g., customized based on mobile network operator (MNO) requirements and/or deployments). Moreover, during PLMN selection, the UE can only search for a RAT that is associated with a MCC/MNC combination, resulting in faster PLMN selection and reduced UE resource consumption. Further, the PLMN selector file can be modified based on MNO preferences via an over-the-air update.