Narrowband Interference Detection via Tone Vector Multiplication

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Solution Overview

Problem

Existing methods for detecting and estimating narrowband interference (NBI) in communication signals, such as electromagnetic interference (EMI), are inefficient and can lead to link drops due to the need for large data collection, especially when signals are degraded by external noise sources like wireless devices.

Innovation Solution

A processing unit selects the strongest tone and adjacent tones in the frequency domain representation of an input signal, multiplies these tones with a predetermined matrix to identify sub-resolution maxima, and determines the presence or absence of NBI and estimates its frequency, reducing the need for extensive data collection and hardware resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If spectral analysis is applied directly to the received signal to detect EMI, then EMI detection capability is improved, but large amounts of data collection is required which increases time consumption and computational complexity

Engineering Contradiction:

ImproveEMI detection capabilityVSAvoiddata collection time

Core Design Contradiction:

Difficulty of detecting and measuringVSLoss of time

Solution Approach 1:

The patent extracts only the essential frequency components (strongest tone and adjacent tones) from the full received signal spectrum, rather than analyzing the entire signal. This extraction approach maintains EMI detection capability while dramatically reducing the data volume that requires processing, thereby decreasing time consumption and computational complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the frequency spectrum into discrete tones and selectively processes only specific tone components (the strongest tone and its adjacent tones) rather than analyzing the continuous spectrum. This segmentation allows focused analysis on potential EMI frequencies without processing the entire signal, reducing both time and computational resources required.

Inventive Principle:

Principle #1Segmentation

2Difficulty of detecting and measuring

If spectral analysis is applied directly to the received signal to detect EMI, then EMI detection capability is improved, but computational complexity increases

Engineering Contradiction:

ImproveEMI detection capabilityVSAvoidcomputational complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial spectral analysis by focusing computational resources on only the most relevant frequency components (strongest tone and adjacent tones) rather than performing exhaustive analysis of the entire spectrum. This partial action approach achieves sufficient EMI detection with significantly reduced computational complexity.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If prior art shielding techniques are used to prevent EMI, then EMI protection is improved, but at high data rates (10 Gbps) the shielding becomes insufficient

Engineering Contradiction:

ImproveEMI protectionVSAvoiddata transmission rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent converts the harmful EMI effect into a detectable signal characteristic. By identifying the characteristic spectral signature of EMI (strongest tone and adjacent tones), the system can detect and potentially compensate for EMI effects rather than relying solely on physical shielding, enabling high data rate transmission even in EMI-prone environments.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Measurement precision

If extensive data collection is performed to detect NBI, then detection accuracy is improved, but link drops occur due to prolonged detection time

Engineering Contradiction:

ImproveNBI detection accuracyVSAvoidlink stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary identification of the strongest tone and its adjacent tones before conducting full spectral analysis. This preliminary action allows the system to focus subsequent processing only on relevant frequency components, achieving accurate NBI detection with minimal data collection time, thereby maintaining link stability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9048930B2Detection and estimation of narrowband interference by matrix multiplication

Publication Date: 2015.06.02 MACOM CONNECTIVITY SOLUTIONS LLC

AI summary

One or more processing units are programmed to select from among M tones in a frequency domain representation of a signal, a set of tones including at least a strongest tone (relative to background noise) and a tone adjacent thereto. From among M complex numbers in the frequency domain representation of the signal, a set of complex numbers are identified and denoted as a vector Z, corresponding to the selected set of tones. Vector Z is then multiplied with each of M columns of a matrix G which is predetermined to identify a sub-resolution maxima in Z. The M products that result from the vector multiplication of Z and G are used to determine and store in memory at least one or both of: (A) a flag indicating presence or absence of narrowband interference in the signal; and (B) an estimate of a frequency of the narrowband interference.