Frequency-Domain Channel Response Filtering for Accurate Motion Detection
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Solution Overview
Problem
Motion detection systems using wireless signals are prone to errors due to device- or system-level impairments, leading to false positives, as changes in frequency-domain channel responses can be caused by noise or distortions unrelated to physical environment changes.
Innovation Solution
A filtering operation is applied to frequency-domain channel responses to remove noise and distortions unrelated to physical environment changes, generating reconstructed channel responses and quality metrics to improve motion detection accuracy by reducing false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless signals are used for motion detection, then motion detection capability is provided, but false positives occur due to device- or system-level impairments
Solution Approach 1:
The patent extracts and removes electronic impairments (noise and distortions) from the channel responses through a filtering operation. The filter is designed to eliminate device- or system-level impairments while preserving motion-related signal characteristics, thereby reducing false positives in motion detection.
Solution Approach 2:
The patent introduces quality metrics as an intermediary mechanism to evaluate and validate channel responses before motion detection. These metrics assess the reliability of channel responses and enable the system to distinguish between genuine motion signals and electronic impairments.
2Reliability
If channel responses are filtered to remove noise, then false positives are reduced, but processing complexity increases
Solution Approach 1:
The patent performs filtering operations and quality metric calculations in advance, before the actual motion detection decision is made. This preliminary processing prepares cleaned channel responses and reliability indicators that can be used efficiently during motion detection, reducing the computational burden at the decision stage.
3Measurement precision
If quality metrics are calculated for each channel response, then false positives are reduced, but computational load increases
Solution Approach 1:
The patent applies quality metric calculation selectively rather than uniformly to all channel responses. The filtering and quality assessment are applied to the extent necessary to achieve reliable motion detection, avoiding unnecessary computational overhead while maintaining detection accuracy.
Data Source
AI summary
In a general aspect, a set of observed frequency-domain channel responses is filtered to remove noise or distortions that are not related to changes in the physical environment. In some aspects, for each frequency-domain channel response, a time-domain channel response is generated based on the frequency-domain channel response; and a filtered time-domain channel response is generated based on a constraint applied to the time-domain channel response. Additionally, a reconstructed frequency-domain channel response is generated based on the filtered time-domain channel response. An error signal is also generated, and a determination is made as to whether the error signal satisfies a criterion. The error signal can be indicative of a difference between the frequency-domain channel response and the reconstructed frequency-domain channel response. In response to each of the error signals satisfying the criterion, motion of an object in a space is detected based on the set of frequency-domain channel responses.