Dynamic Preferred PLMN List for Faster Roaming Service Acquisition
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Solution Overview
Problem
User devices face prolonged service acquisition times when roaming in regions with numerous Public Land Mobile Networks (PLMNs) due to limited preferred PLMN lists on SIM cards, which do not cover areas like India, South America, and Asia, leading to inefficient network selection and frequent reconnection attempts.
Innovation Solution
A user device with a wireless modem and processor that stores and dynamically updates a list of preferred wireless networks based on data collected from multiple user devices, allowing for selection and registration with available networks, and updates the list based on successful or unsuccessful registration attempts, thereby optimizing network selection and acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a user device uses a traditional SIM card stored preferred PLMN list for network selection, then the device can operate in automatic selection mode with predefined network priorities, but the list does not cover regions like India, South America and Asia, leading to prolonged service acquisition times
Solution Approach 1:
The system performs preliminary actions by collecting network data from multiple user devices in advance, identifying available PLMNs and their characteristics before a user device needs to roam. This pre-collected data is processed to create region-specific preferred PLMN lists that cover areas like India, South America and Asia, so when a user device needs to acquire service in these regions, it can immediately use the pre-prepared list rather than searching randomly.
Solution Approach 2:
An intermediary system (server or cloud platform) is introduced between user devices and PLMNs. This intermediary collects network data from multiple devices, processes it to identify suitable PLMNs for specific regions, and generates preferred PLMN lists that are then distributed to user devices. This intermediary enables the system to overcome the limitation of individual SIM card storage capacity by centralized data aggregation and processing.
2Productivity
If a user device randomly selects PLMNs with sufficient signal strength when no preferred list is available, then the device can attempt service acquisition, but it may have to hop between many different PLMNs until service is acquired
Solution Approach 1:
The system implements feedback mechanisms where user devices report their network selection outcomes (successful service acquisition or rejection) back to the intermediary system. This feedback is used to continuously refine and update the preferred PLMN lists, removing networks that consistently reject devices and prioritizing networks with higher success rates. This learning process improves network selection efficiency over time, reducing the number of hops needed to acquire service.
Solution Approach 2:
Instead of random selection, the system performs preliminary filtering of available PLMNs based on pre-collected data about which networks have roaming agreements and are likely to accept the user device. This preliminary action narrows down the selection pool to high-probability candidates before the device attempts connection, avoiding wasted attempts on networks that would reject the device anyway.
3Ease of operation
If a user device operates in manual selection mode and presents a list of available PLMNs to the user, then the user can select a specific PLMN, but the user has to review the list and select a specific PLMN which is inconvenient and time-consuming
Solution Approach 1:
The system enables self-service by automatically performing the network selection process without requiring user intervention. The intermediary system or device autonomously evaluates available PLMNs against the preferred list, selects the most suitable network based on predefined criteria (roaming agreements, signal strength, historical success rates), and initiates connection attempts. This eliminates the need for users to manually review and select from lengthy PLMN lists.
Solution Approach 2:
The system performs preliminary evaluation and ranking of available PLMNs based on pre-collected data and device-specific criteria before presenting options to the user or automatically selecting. This preliminary action filters out unsuitable networks and prioritizes the most promising candidates, so if manual selection is needed, the user sees a shortened, pre-sorted list rather than all available networks.
4Adaptability or versatility
If preferred PLMN lists are stored on SIM cards with limited storage space, then the lists can be maintained on the device, but they typically cover only U.S., Canada and Europe and do not cover several regions including India, South America and Asia
Solution Approach 1:
An intermediary system (server or cloud platform) is introduced to store and manage comprehensive preferred PLMN lists that exceed SIM card storage capacity. This intermediary aggregates network data from multiple sources, maintains updated lists for numerous regions including India, South America and Asia, and distributes relevant portions to user devices as needed. The intermediary acts as an external storage extension that overcomes the physical storage limitations of SIM cards.
Solution Approach 2:
The system performs preliminary aggregation and organization of PLMN data for multiple regions in advance, creating comprehensive preferred lists that cover areas beyond traditional Western markets. This pre-processed data is then made available to user devices through the intermediary system, allowing devices to access region-specific lists without storing all possible network data locally on the SIM card.
Data Source
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AI summary
A user device determines whether a modem specifies at least one network present at a current geographical location of the user device. When the modem does not specify any present networks, the user device identifies one of the present networks that is available to provide a roaming service to the user device, and adds the identified network to a list of preferred networks in the modem.