Adaptive K-Means Clustering for Indoor Localization Models

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Solution Overview

Problem

Existing indoor localization models struggle to differentiate between smaller and larger areas using mean signal strength scans, especially in complex environments like buildings with many rooms and hallways, due to the computational difficulty of K-means clustering and the need for determining optimal K values.

Innovation Solution

An adaptive K-means clustering method is employed, involving a split phase to increase K dynamically based on scan vector similarities and a merge phase to combine similar clusters, along with re-centering and post-filtering processes to refine cluster accuracy and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If K-means clustering is used to create indoor localization models, then the ability to differentiate between areas of varying sizes is improved, but the computational complexity increases

Engineering Contradiction:
Improvelocation differentiation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a dynamic K-means clustering approach where the number of clusters K is not fixed but adaptively determined through a two-phase process: a split phase that increases K when clusters are too large, and a merge phase that decreases K when clusters are too small. This dynamic adjustment resolves the contradiction by optimizing location differentiation accuracy while managing computational complexity through adaptive rather than exhaustive computation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary actions by establishing initial clusters and then iteratively refining them through split and merge phases. The algorithm pre-processes the data by creating initial cluster assignments and then systematically improves them through controlled iterations, reducing the overall computational burden compared to attempting to determine the optimal K value directly from the beginning.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If a small value for K is used in K-means clustering, then the computational efficiency is improved, but the ability to differentiate between similar areas deteriorates

Engineering Contradiction:
Improveclustering efficiencyVSAvoidarea differentiation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts K during the clustering process rather than using a fixed small value. The split phase increases K when clusters contain too many elements, and the merge phase decreases K when clusters are too fine-grained. This dynamic approach maintains computational efficiency by starting with a reasonable initial K while improving area differentiation accuracy through adaptive refinement based on actual data characteristics.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The algorithm incorporates feedback mechanisms where cluster characteristics (size, density, spatial distribution) are continuously evaluated during the split and merge phases. This feedback loop allows the system to automatically adjust K to achieve optimal differentiation accuracy without requiring manual intervention or exhaustive computation, thus maintaining efficiency while improving precision.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If K is increased to improve cluster granularity, then the differentiation between areas is improved, but the computational difficulty increases

Engineering Contradiction:
Improvecluster granularityVSAvoidcomputational difficulty
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the clustering process into distinct phases: an initial clustering phase, a split phase for increasing granularity, and a merge phase for reducing complexity. This segmentation allows the algorithm to achieve high cluster granularity when needed while managing computational difficulty by processing adjustments in controlled steps rather than attempting to determine the final optimal structure all at once.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adjustment of cluster granularity through the split and merge phases. Rather than committing to a high K value from the start (which would increase computational difficulty), the algorithm starts with a moderate K and dynamically increases granularity only where and when needed based on data characteristics, thus achieving high precision without proportional increases in computational difficulty.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If iterative K-means clustering is performed to achieve optimal clusters, then the localization accuracy is improved, but the time consumption increases

Engineering Contradiction:
Improvelocalization accuracyVSAvoidmodel generation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary clustering to establish initial cluster assignments before executing the split and merge refinement phases. This preliminary action provides a reasonable starting point that reduces the number of iterations needed to achieve optimal localization accuracy, thereby reducing time consumption compared to starting from scratch or using more exhaustive optimization methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The algorithm dynamically determines when to stop iterating through the split and merge phases based on convergence criteria or maximum iteration limits. This dynamic termination strategy ensures that the model achieves sufficient localization accuracy without unnecessary additional iterations that would only increase time consumption, thus optimizing the trade-off between accuracy and time.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4276487B1Generating wireless network access point models using clustering techniques
Publication Date: 2025.06.04 GOOGLE LLC
  • EP4276487B1 patent drawingFigure 1
  • EP4276487B1 patent drawingFigure 2
  • EP4276487B1 patent drawingFigure 3

AI summary

The technology relates to generating a wireless network access point model for determining locations within an area. In one example, a plurality of scan vectors, each scan vector representing a set of signal strengths for a set of wireless network access point identifiers and being associated with a location within the area at which a mobile device moving through the area measured the set of signal strengths are received. A set of clusters is generated by iterating through a split phase until the number of clusters in the set of clusters equals a maximum number of clusters or there are no bad scan vectors identified. A bad scan vector may include a vector having a vector difference from a center of a cluster to which that vector is assigned is less than a minimum similarity value. The set of cluster is then used to generate the model of the area.