Mobile Device Cellular Network Selection via Frequency Lists

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Solution Overview

Problem

Current cellular network selection methods in mobile devices are inefficient, particularly when traveling to foreign countries, as they require extensive scanning of multiple radio frequency bands and access technologies, leading to delayed service activation and increased battery consumption.

Innovation Solution

A method that prioritizes scanning a 'likely frequency list' composed of commonly deployed frequencies at specific locations, such as airports, in conjunction with a 'most recently used' frequency list, to quickly identify usable channels upon transceiver activation, reducing the need for exhaustive scans.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mobile device performs an exhaustive scan of all radio frequency bands and access technologies to ensure comprehensive network selection, then the reliability of network selection is improved, but the time required for network selection and battery consumption increase significantly

Engineering Contradiction:
Improvenetwork selection reliabilityVSAvoidnetwork selection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the network selection process into two distinct phases: a rapid initial scan of a limited subset of frequencies (most recently used and likely frequencies) to quickly establish service, followed by a subsequent exhaustive scan to ensure comprehensive network selection. This segmentation resolves the contradiction by allowing the device to achieve acceptable reliability through the second phase without suffering the time penalty of performing the exhaustive scan from scratch during initial activation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-populating the device with a 'most recently used' frequency list and a 'likely frequency' list before the device is activated. These pre-prepared lists contain frequencies that are statistically most likely to be available, allowing the device to perform a rapid initial scan without having to scan all possible frequencies. This preliminary preparation resolves the contradiction by enabling fast initial network selection while maintaining the option to perform comprehensive scanning later if needed.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a mobile device performs an exhaustive scan of all radio frequency bands and access technologies to ensure comprehensive network selection, then the reliability of network selection is improved, but battery consumption increases significantly

Engineering Contradiction:
Improvenetwork selection reliabilityVSAvoidbattery consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the network selection process into two distinct phases: a rapid initial scan of a limited subset of frequencies (most recently used and likely frequencies) to quickly establish service, followed by a subsequent exhaustive scan to ensure comprehensive network selection. This segmentation resolves the contradiction by allowing the device to achieve acceptable reliability through the second phase without suffering the time penalty of performing the exhaustive scan from scratch during initial activation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-populating the device with a 'most recently used' frequency list and a 'likely frequency' list before the device is activated. These pre-prepared lists contain frequencies that are statistically most likely to be available, allowing the device to perform a rapid initial scan without having to scan all possible frequencies. This preliminary preparation resolves the contradiction by enabling fast initial network selection while maintaining the option to perform comprehensive scanning later if needed.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If a mobile device scans all radio frequency bands in a 3GPP-specified order to ensure comprehensive network selection, then the adaptability to different network environments is improved, but the time required for network selection increases

Engineering Contradiction:
Improvenetwork environment adaptabilityVSAvoidnetwork selection time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies local quality by making the frequency scan order context-dependent rather than uniform. Specifically, the device checks whether it is in a roaming environment and adjusts the scan priority accordingly: in roaming environments, it scans foreign network frequencies first, while in home environments, it scans home network frequencies first. This localized adaptation to different operational contexts resolves the contradiction by enabling the device to adapt to different network environments without always performing the full 3GPP-specified scan sequence.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by pre-populating the device with a 'most recently used' frequency list and a 'likely frequency' list before the device is activated. These pre-prepared lists contain frequencies that are statistically most likely to be available, allowing the device to perform a rapid initial scan without having to scan all possible frequencies. This preliminary preparation resolves the contradiction by enabling fast initial network selection while maintaining the option to perform comprehensive scanning later if needed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3225057B1Selecting a cellular network by a mobile device upon its activation
Publication Date: 2020.10.07 BLACKBERRY LTD
  • EP3225057B1 patent drawingFigure 1
  • EP3225057B1 patent drawingFigure 2
  • EP3225057B1 patent drawingFigure 3

AI summary

A method performed by a mobile device of selecting a cellular network entails activating a cellular radio transceiver, scanning a most recently used frequency list of radiofrequency channels most recently used by the cellular radio transceiver of the mobile device, scanning a likely frequency list of likely radiofrequency channels available at a plurality of locations where activation of cellular radio transceivers commonly occurs, and selecting the cellular network by identifying one of the radiofrequency channels as a usable channel.