WiFi Radar Chirp Interference Detection in Co-Channel Signals
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Solution Overview
Problem
WiFi radar frames are vulnerable to interference from other wireless signals, such as WiFi, Bluetooth, and Zigbee, which affects the accuracy and reliability of radar detection.
Innovation Solution
A WiFi radar communication circuit with a radio frequency front-end, analog-to-digital converter, and digital signal processor is used to determine interference by calculating cumulative power differences between adjacent reflected chirps and performing statistical analysis to generate interference detection results for both individual chirps and frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WiFi radar frames are transmitted in co-channel environments, then radar sensing capability is enabled using existing WiFi hardware, but the radar frames become vulnerable to interference from other wireless signals (WiFi, Bluetooth, Zigbee) affecting detection accuracy
Solution Approach 1:
The interference detector performs preliminary detection on each reflected chirp to identify interference before the chirp is used for radar measurement. By calculating cumulative power differences between adjacent chirps and comparing against thresholds, the system proactively identifies interfered chirps and discards them before they can degrade the final radar measurement accuracy.
Solution Approach 2:
The system implements a feedback mechanism where interference detection results from individual chirps are aggregated to determine overall frame interference status. The statistical analysis of chirp-level interference results provides feedback that determines whether the entire radar frame should be discarded, creating a multi-level feedback loop that improves detection reliability.
2Measurement precision
If interference detection is performed on each reflected chirp using cumulative power difference calculation, then interference identification accuracy is improved, but the computational complexity and processing time increase
Solution Approach 1:
The system performs interference detection on individual reflected chirps within a frame rather than analyzing the entire frame at once. This partial action approach allows interference identification at the chirp level with manageable computational complexity, and only interfered chirps are discarded while valid chirps are retained for measurement.
Solution Approach 2:
The interference detection method uses cumulative power difference as a key parameter to identify interference. By monitoring changes in power parameters between adjacent chirps and comparing against dynamically adjusted thresholds, the system achieves accurate interference detection through parameter transformation rather than complex signal analysis.
3Reliability
If severely interfered radar frames are discarded, then detection accuracy is maintained, but the number of valid measurements decreases
Solution Approach 1:
The radar frame is segmented into individual reflected chirps for independent interference evaluation. This segmentation allows the system to discard only the interfered chirps while retaining valid ones, rather than discarding the entire frame. The chirp-level granularity enables selective filtering that maintains measurement productivity while ensuring accuracy.
Solution Approach 2:
The system discards only those chirps that are identified as severely interfered through the interference detection mechanism, while recovering and retaining the valid chirps for radar measurement. This selective discarding approach minimizes the loss of valid measurements while maintaining detection accuracy by eliminating only the corrupted data.
Data Source
AI summary
A WiFi radar communication circuit includes a radio frequency front-end circuit, an analog-to-digital converter, and a digital signal processor. The radio frequency front-end circuit is coupled to a transmitting antenna and a receiving antenna for transmitting a radar frame and receiving reflected echoes. The analog-to-digital converter is configured to convert the reflected echoes into radar echo digital signals. The digital signal processor is configured to operate an interference detector. The interference detector is configured to determine whether each reflected chirp among the reflected chirps is subject to interference based on a cumulative power difference between adjacent reflected chirps. The interference detector is further configured to determine whether the radar frame is subject to interference based on a statistical result of whether the reflected chirps are subject to interference. Accordingly, interference detection results for the radar frame and the reflected chirps are generated.