WLAN Client Localization via Dynamic Reference Points

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Solution Overview

Problem

Existing indoor navigation methods using WLAN networks require a large number of static reference points for accurate localization, which is time-consuming and costly, and do not perform well in closed environments like buildings, while scene analysis methods face challenges in identifying client positions with high precision.

Innovation Solution

The method involves self-learning dynamic reference points by measuring field strengths with moving WLAN clients, combining them with static reference points using scene analysis, and calculating the center of gravity for precise localization, allowing for accurate indoor navigation with fewer static points and adapting to changes in the environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of static reference points are used for accurate localization, then localization precision is improved, but the time and cost for setup increases

Engineering Contradiction:
Improvelocalization accuracyVSAvoidsetup time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces dynamic reference points that are automatically generated through client movement and field strength measurement, replacing the static reference point setup. This allows the system to adaptively create reference data during normal operation rather than requiring manual pre-configuration of numerous fixed points, thereby reducing setup time while maintaining localization accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-learning by automatically generating dynamic reference points through clients moving through the environment and measuring field strengths. This self-service mechanism eliminates the need for manual setup of static reference points, as the system autonomously creates and updates its own reference database during normal operation, significantly reducing setup time and cost.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If scene analysis method is used for localization, then localization precision is improved, but the complexity of data records increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoiddata record complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the reference points into two categories: static reference points with fixed spatial coordinates and dynamic reference points generated through client movement. This segmentation allows the system to manage complexity by organizing data records into distinct types with different characteristics, making the overall system more manageable while maintaining high localization precision through scene analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the parameters of reference points from purely static to including dynamic components generated through client movement. By transforming reference points into a mix of static and dynamically generated entries, the system reduces the overall complexity burden while maintaining the precision benefits of comprehensive scene analysis data.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If static reference points are used for localization, then the system is simpler to implement, but adaptability to environmental changes decreases

Engineering Contradiction:
Improvesystem implementation simplicityVSAvoidtolerance to environmental changes
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic reference points that are automatically generated and updated as clients move through the environment, replacing purely static reference points. This dynamic approach allows the system to automatically adapt to environmental changes such as furniture rearrangement or construction progress, while maintaining the simplicity of the overall implementation by automating the adaptation process rather than requiring manual updates.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback mechanisms where client movements and field strength measurements continuously update the dynamic reference points. This feedback loop enables the system to automatically adapt to environmental changes by learning from actual client experiences, while the automated nature of the feedback process maintains implementation simplicity compared to manual system updates.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If geometric measuring method is used to determine reference points, then localization precision is improved, but the time expenditure increases

Engineering Contradiction:
Improveposition accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual geometric measurement methods with automated field strength-based measurement. Instead of requiring physical surveying and geometric calculations to establish reference points, the system uses wireless field strength measurements taken during normal client movement to automatically generate reference data, significantly reducing the time expenditure while maintaining localization precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-learning by automatically generating reference points through client movement and field strength measurement, eliminating the need for manual geometric surveying. This self-service approach allows the system to create its own reference database during normal operation, reducing time expenditure while maintaining the precision benefits of accurate position determination.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly improves localization accuracy with fewer static reference points, achieving nearly 99% hit probability and tolerating changes in the environment, such as furniture rearrangement, without the need for extensive geometric measurements, and can determine position even when some WLAN stations are not received.

Implementation Method 1

measuring field strengths of the WLAN stations at known spatial coordinates

Methodology Applied
Scientific EffectElectromagnetic field measurement: Electric Field

Data Source

PatentUS7974632B2Method and system for the localization of a mobile WLAN client
Publication Date: 2011.07.05 DEUTSCHE TELEKOM AG
  • US7974632B2 patent drawing
  • US7974632B2 patent drawing
  • US7974632B2 patent drawing

AI summary

A method and a system for the localization of a mobile WLAN client, located within a WLAN network of multiple WLAN stations. Static reference points are ascertained by measuring field strengths of the WLAN stations at spatial coordinates, aided by WLAN client(s), and assignment of the measured field strengths to the spatial coordinates in terms of data records. Self-learning ascertainment of further dynamic reference points is obtained by measuring field strengths of the WLAN stations, aided by WLAN client(s) moving through the region of the network, and assignment of the measured field strengths in terms of data records to the respective spatial coordinates calculated for this purpose, in the database server. This may be done to localize a WLAN client by selecting a plurality of nearest matched data records of static and dynamic reference points whose subsequently calculated center of gravity corresponds to the estimated position of the WLAN client.