Wi-Fi Signal Classification Using Fourier Transform Slope Analysis

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Solution Overview

Problem

Existing Wi-Fi detection methods face challenges in accurately classifying Wi-Fi signals from Fourier Transform samples due to interference from non-Wi-Fi devices, leading to false detections and inefficient channel utilization.

Innovation Solution

The proposed solution involves classifying Wi-Fi signals by analyzing Fourier Transform samples through criteria such as slope values, sub-peak frequency bins, adjacent channel analysis, and characteristic matching, to differentiate between Wi-Fi and non-Wi-Fi signals, thereby minimizing false detections and improving channel utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Wi-Fi detection is performed using Fourier Transform samples, then channel utilization monitoring is enabled, but false detections increase due to interference from non-Wi-Fi devices

Engineering Contradiction:
Improvechannel utilization monitoringVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by analyzing specific local characteristics of Fourier Transform samples, such as slope values at particular frequency bins and patterns in adjacent channels, to distinguish Wi-Fi signals from non-Wi-Fi interference. Instead of treating all samples uniformly, the system focuses on localized features that are characteristic of Wi-Fi transmissions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters by comparing multiple characteristics of the samples including slope values, frequency bin patterns, and adjacent channel information. By analyzing changes in these parameters and comparing them against expected Wi-Fi signal characteristics, the system can differentiate between actual Wi-Fi signals and interference from other devices.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If sophisticated spectrum analyzers are used to identify interference sources, then detection accuracy improves, but device complexity and cost increase

Engineering Contradiction:
Improveinterference detection accuracyVSAvoidanalyzer complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables Wi-Fi devices to perform their own interference detection and classification using the Fourier Transform samples already being processed for normal operation. The system uses self-service by leveraging existing signal processing capabilities to additionally identify and classify interference sources without requiring separate sophisticated measurement equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent makes the existing signal processing system multi-functional by enabling it to both monitor channel utilization and classify interference sources using the same Fourier Transform samples. This universality allows the system to perform multiple functions with a single processing pipeline, avoiding the need for additional specialized equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If Wi-Fi frames are classified as interferers based on fixed FFT signatures, then interference identification is simplified, but false detections increase

Engineering Contradiction:
Improveclassification simplicityVSAvoidfalse detection rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by examining specific local features of the FFT signatures, such as slope values at particular frequency bins and patterns in adjacent channels, rather than relying on overall fixed signature patterns. This localized analysis allows differentiation between Wi-Fi frames and other signals that may have similar general characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent inverts the traditional approach by not assuming all fixed FFT signatures are Wi-Fi interferers, but rather by using the fixed signature as a starting point and then applying additional local quality checks to confirm whether the signal is actually Wi-Fi. This inversion of the classification logic reduces false detections.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentUS9467893B2Analyzing a particular wireless signal based on characteristics of other wireless signals
Publication Date: 2016.10.11 HEWLETT PACKARD ENTERPRISE DEV LP
  • US9467893B2 patent drawing
  • US9467893B2 patent drawing
  • US9467893B2 patent drawing

AI summary

The present disclosure discloses a system and method for classifying Wi-Fi signals from Fourier transform samples. Generally, classifying Wi-Fi signals from Fourier transform samples includes: collecting and dividing Fourier transform samples into frequency blocks; determining the bandwidth for the Fourier transform sample; and determining whether the Fourier transform sample corresponds to a narrowband signal. Further, if a determination is made that the Fourier transform sample does not correspond to a narrowband signal, channel utilization is calculated based on a determination that the FFT sample corresponds to a Wi-Fi signal. If it is determined that the Fourier transform sample corresponds to a narrowband signal, then a determination is made that the FFT sample corresponds to a Wi-Fi signal based on certain criteria. The certain criteria may include one or more of a slope value, a number of sub-peak bins, an analysis of adjacent channels, characteristic matching, or other criteria.