Wireless Interference Classification from Partial Spectrum Signatures

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Solution Overview

Problem

Wireless networks face challenges in classifying non-network interference sources due to limited information and the need to differentiate between intermittent and continuous interference, frequency coverage, and power levels, using only the receivers present in devices like access points and laptops.

Innovation Solution

Wireless receivers are switched to a spectrum monitor mode to collect amplitude-versus-frequency information using FFT, calibrated with known interference sources to match interference signatures, and record noise floor variations to accurately classify interferers, even in the presence of multiple competing signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If wireless receivers are used to detect interference sources, then interference detection capability is provided, but measurement precision deteriorates due to limited information from minimal or incomplete signals

Engineering Contradiction:
Improveinterference detection capabilityVSAvoidinterference classification accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by switching receivers to spectrum monitor mode before full interference analysis, collecting amplitude-versus-frequency information in advance. This preliminary spectral data gathering enables more accurate interference classification even when signal information is minimal or incomplete, as the receiver captures baseline characteristics before interference fully manifests.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the interference detection problem from time-domain signal analysis to frequency-domain spectral analysis. By applying FFT or similar transforms to convert time-series signals into spectral representations, the system gains additional dimensional information (frequency spectrum) that enhances measurement precision without requiring more receivers or signal strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If spectrum monitor mode is used to collect amplitude-versus-frequency information, then interference classification accuracy is improved, but device complexity increases due to mode switching and calibration requirements

Engineering Contradiction:
Improveinterference classification accuracyVSAvoidreceiver operation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The wireless receiver is designed with multi-functionality, capable of operating in both normal communication mode and spectrum monitor mode. This universal design allows the same hardware to perform dual functions without requiring separate dedicated interference detection equipment, thereby improving measurement precision while limiting the increase in device complexity to software/control logic rather than additional hardware.

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

Solution Approach 2:

The system performs self-calibration by comparing collected spectral information against known interference source profiles stored in the system. This self-service approach enables automatic interference classification without requiring manual calibration procedures or external reference equipment, reducing operational complexity while maintaining high classification accuracy.

Inventive Principle:
Principle #25Self-service

3Reliability

If calibration with known interference sources is performed, then classification reliability is improved, but loss of time increases due to calibration process requirements

Engineering Contradiction:
Improveclassification reliabilityVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs calibration actions preliminarily by pre-loading known interference source profiles into the system before actual interference detection begins. This preliminary preparation of reference data enables rapid comparison and classification during operation, improving classification reliability while minimizing the time lost during actual interference detection events.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The calibration process is designed to be continuous rather than periodic. The system continuously collects spectral information and updates interference profiles in real-time, maintaining reliable classification without requiring periodic calibration interruptions. This continuous operation eliminates downtime associated with traditional calibration schedules while sustaining high classification reliability.

Inventive Principle:
Principle #20Continuity of useful action

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 method enables effective classification of interference sources, reducing false detections and improving the ability to detect multiple interferers, allowing for better management and optimization of wireless network performance.

Implementation Method 1

collect amplitude-versus-frequency information for a chosen part of the spectrum, for example, by performing a FFT or similar transform on the received signals

Methodology Applied
Scientific EffectFast Fourier Transform:

Data Source

PatentUS9130871B2Interference classification with minimal or incomplete information
Publication Date: 2015.09.08 HEWLETT PACKARD ENTERPRISE DEV LP
  • US9130871B2 patent drawing
  • US9130871B2 patent drawing
  • US9130871B2 patent drawing

AI summary

Interference classification with minimal or incomplete information. Receivers in access points and in other network devices on a wireless digital network may be switched to a spectrum monitor mode in which they provide amplitude-versus-frequency information for a chosen part of the spectrum. This may be performed by performing a FFT or similar transform on the signals from the receiver. Receivers are calibrated with known interference sources in controlled environments to determine peaks, pulse frequency, bandwidth, and other identifying parameters of the interference source in best and worst case conditions. These calibrated values are used for matching interference signatures. Calibration is also performed using partial signatures collected over a short period in the order of microseconds. These partial signals may be used to detect interferers while scanning.