Adaptive Impulse Noise Suppression in Wireless Receivers
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Solution Overview
Problem
Existing wireless communication systems struggle with impulsive noise (IN) that causes significant degradation in receiver performance due to its high power and random occurrence, which current methods like high pass filters, frequency domain conversion, and clipping fail to adequately mitigate, especially in-band IN, leading to increased bit error rates and reduced throughput.
Innovation Solution
A real-time method in the time domain detects and removes impulsive noise by determining a moving difference of successive signal samples and comparing them to an adaptive threshold, setting excessive samples to zero, and adjusting the threshold based on signal variance and power to differentiate between signal power and impulsive noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high pass filters are used to mitigate out-of-band impulsive noise, then noise reduction is achieved, but implementation cost increases and in-band impulsive noise is not addressed
Solution Approach 1:
The patent extracts and removes impulsive noise components from the received signal by detecting samples that exceed adaptive thresholds and setting them to zero or interpolated values, thereby separating the harmful noise from the desired signal without requiring complex filtering hardware
Solution Approach 2:
The patent changes the threshold parameter dynamically by making it adaptive based on signal statistics (standard deviation of signal samples), allowing the system to distinguish between impulsive noise and legitimate high-amplitude signal components under varying channel conditions
2Object-affected harmful factors
If frequency domain conversion is used for noise mitigation, then noise processing capability is improved, but implementation complexity and latency increase
Solution Approach 1:
The patent replaces the mechanical/computational process of frequency domain conversion (FFT/IFFT operations) with a simpler time domain operation that computes moving differences and compares against thresholds, achieving noise mitigation without the complexity of frequency domain transformations
Solution Approach 2:
The patent segments the signal processing task by identifying and treating impulsive noise samples individually through moving difference computation, rather than processing the entire signal block through complex frequency domain operations
3Object-affected harmful factors
If clipping is used to mitigate impulsive noise, then noise reduction is achieved, but signal distortion increases due to high clipping threshold
Solution Approach 1:
The patent makes the noise mitigation threshold dynamic and adaptive rather than fixed, adjusting it based on the standard deviation of signal samples to accurately distinguish between impulsive noise and legitimate signal variations, thereby avoiding signal distortion
4Measurement precision
If factory calibration is performed for glitch suppression, then timing precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent enables the system to self-calibrate by computing the delay value automatically using correlation-based methods on received signals, eliminating the need for manual factory calibration and reducing manufacturing complexity while maintaining precision
Data Source
AI summary
A method, network node and wireless device (WD) for suppressing impulsive noise are provided. According to one aspect, a method includes determining a moving difference of successive samples of a received signal, comparing the moving difference to a threshold, and setting the successive samples to a predetermined value when the moving difference exceeds the threshold.