Dual High-Pass Filter Selection Under Out-of-Band Interference
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Solution Overview
Problem
Existing impulse noise mitigation techniques in wireless communication receivers are ineffective in detecting impulse noise under high carrier-to-interference ratios in the time domain and are unreliable due to out-of-band interferers in the frequency domain, leading to inaccurate demodulation of digital signals.
Innovation Solution
The implementation of two complex high pass filters that selectively admit frequency components above and below the desired signal bandwidth, with a state machine determining which filter to use based on mean magnitude measurements over a time interval T to minimize noise and interference, thereby improving impulse noise detection and mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency domain impulse noise mitigation is applied, then impulse noise is reduced, but out-of-band interference causes false detection and reduces reliability
Solution Approach 1:
The patent divides the frequency domain analysis into two separate detection paths: one for impulse noise detection and another for out-of-band interference detection. By segmenting the detection functions, the system can distinguish between actual impulse noise and false indications caused by out-of-band interference, thereby improving detection reliability while maintaining impulse noise mitigation capability.
2Measurement precision
If impulse noise detection sensitivity is increased, then more impulse noise is detected, but false positives from out-of-band interference increase
Solution Approach 1:
The patent introduces an intermediary verification mechanism that cross-checks impulse noise detection results against out-of-band interference measurements. Before confirming impulse noise presence, the system uses the intermediary out-of-band interference detector to verify whether detected anomalies are genuine impulse noise or false positives caused by interference, thus reducing false positives while maintaining detection sensitivity.
Data Source
AI summary
An impulse noise mitigation circuit (INMC) may set a cut-off frequency of each of two high pass filters to bound a frequency bandwidth of a desired signal, wherein a first of the two filters allows frequencies higher than the frequency bandwidth of the desired signal, and a second of the two filters allows frequencies lower than the frequency bandwidth of the desired signal. The INMC may compute and store a mean magnitude separately for a first signal response of the first filter and a second signal response of the second filter. The INMC may select the first filter for impulse noise mitigation when the mean magnitude of the second filter is greater than the mean magnitude of the first filter. The INMC may select the second filter for impulse noise mitigation when the mean magnitude of the first filter is greater than the second filter.