Time Domain Noise Suppression for Speech Signals

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Solution Overview

Problem

Traditional noise suppression techniques in wireless communication systems are complex, introduce latency, and can distort speech quality due to their reliance on spectrum domain manipulation, and they are not effective in the down-link direction, leading to poor user experience and unnecessary bandwidth consumption.

Innovation Solution

A low-complexity noise suppression system operating entirely in the time domain, using a single microphone and calculating a gain factor based on detected noise and signal levels to reduce noise without converting signals between domains, suitable for both up-link and down-link directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional spectrum domain noise suppression techniques are used, then noise reduction effectiveness is improved, but computational complexity increases and latency is introduced

Engineering Contradiction:

Improvenoise reduction effectivenessVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional spectrum domain processing mechanism with a time domain-based noise suppression mechanism. Instead of using complex spectral analysis and inverse transforms, the system applies a simplified time-domain algorithm that directly processes audio signals, reducing computational complexity while maintaining noise reduction effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the processing domain parameter from frequency domain to time domain. This fundamental parameter change allows the system to achieve noise suppression without the computational burden of spectral analysis, transforming the approach from traditional spectrum-based methods to a more efficient time-based method.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If spectrum domain manipulation techniques are used, then noise suppression capability is improved, but speech quality distortion increases

Engineering Contradiction:

Improvenoise suppression capabilityVSAvoidspeech quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent substitutes the spectrum domain manipulation mechanism with a time domain processing mechanism. This replacement avoids the spectral distortion artifacts that occur during transform and inverse transform operations, preserving natural speech quality while maintaining noise suppression capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If spectrum domain noise suppression is applied, then noise reduction is improved, but processing latency increases

Engineering Contradiction:

Improvenoise reductionVSAvoidprocessing latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the multi-step spectral processing system (FFT, spectrum manipulation, IFFT) with a direct time domain algorithm. This substitution eliminates the time-consuming transform operations, significantly reducing processing latency while maintaining effective noise reduction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If traditional noise suppression techniques are used, then up-link noise reduction is improved, but down-link noise suppression is not effective

Engineering Contradiction:

Improveup-link noise reductionVSAvoidbidirectional applicability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs a noise suppression system that is universally applicable to both up-link and down-link communication directions. The time domain algorithm provides bidirectional functionality, allowing the same mechanism to effectively suppress noise in both transmission and reception paths, unlike traditional unidirectional approaches.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9934791B1Noise supressor

Publication Date: 2018.04.03 QOSOUND IP INNOVATIONS LLC

AI summary

Provided is a method, non-transitory computer program product and system for an improved noise suppression technique for speech enhancement. It operates on speech signals from a single source such as either the output from a single microphone or the reconstructed speech signal at the receiving end of a communication application. The system performs background noise monitoring of an in-coming speech signal and determines its level, and performs a time domain gain calculation. The noise suppressed output signal is the gain shaped original speech signal.