Geolocation via Signal Strength Attenuation Modeling

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Solution Overview

Problem

Existing wireless communication networks, particularly asynchronous networks like LTE, face challenges in accurately geolocating wireless communication units due to the lack of timing offset information, making it difficult to determine distance from cell sites and requiring alternative methods to model signal strength contours effectively.

Innovation Solution

A method using a genetic algorithm to derive signal strength attenuation characteristic values for cells within a wireless communication network, based on signal strength measurements from subscriber units, to accurately model signal strength contours and enable precise geolocation of wireless communication units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If timing information methods are used for geolocation in asynchronous networks, then location estimation can be performed, but the lack of timing offset information makes it difficult to determine accurate distance from cell sites

Engineering Contradiction:
Improvedistance estimation accuracyVSAvoidtiming offset information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent changes the parameter used for geolocation from timing information to signal strength information. By using signal strength measurements and deriving attenuation characteristic values, the system compensates for the lack of timing offset information in asynchronous networks, enabling distance estimation through a different physical parameter that is available in the network.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If signal strength measurements are used to determine distance, then geolocation can be achieved without timing information, but signal strength varies significantly with environment making accurate distance estimation difficult

Engineering Contradiction:
Improvedistance estimation accuracyVSAvoidenvironmental variability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary actions by collecting signal strength measurements from multiple subscriber units in the same environment and deriving attenuation characteristic values before using them for geolocation. This pre-characterization of the environment creates a baseline that accounts for environmental factors, allowing more accurate distance estimation when actual geolocation is performed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing measured signal strengths with expected signal strengths based on derived attenuation characteristics. The difference between measured and expected values provides information about location accuracy and environmental deviations, allowing the system to refine its estimates and account for environmental variability.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If GPS is used for geolocation, then accurate location can be obtained, but it causes significant power drain on the device's battery

Engineering Contradiction:
Improvelocation accuracyVSAvoidbattery power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The network performs geolocation services using signal strength measurements that are already being collected for network operations. Instead of requiring the mobile device to actively measure and report GPS coordinates (consuming device battery), the network uses existing signal strength data from the air interface to determine location, making the device energy-independent for this function.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2941035B1Method and apparatus for geolocation of a wireless communication subscriber unit
Publication Date: 2018.10.24 VIAVI SOLUTIONS UK LTD
  • EP2941035B1 patent drawingFigure 1
  • EP2941035B1 patent drawingFigure 2
  • EP2941035B1 patent drawingFigure 3

AI summary

Methods and devices for deriving signal strength attenuation characteristic values for cells within a wireless communication network. The method comprises determining a set of cells for which signal strength attenuation characteristic values are to be derived, and using a genetic algorithm to derive signal strength attenuation characteristic values for the set of cells based at least partly on signal strength information for signal strength measurements obtained by wireless communication subscriber units within the wireless communication network. Application in the field of geolocation of mobile users.