WLAN Radar Pulse Reconstruction via PRI Calibration
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Solution Overview
Problem
WLAN devices operating in dynamic frequency selection (DFS) channels face challenges in detecting radar signals due to channel and filtering effects, which lead to shortened pulse width and pulse repetition interval, resulting in decreased radar detection probability and increased interference.
Innovation Solution
A WLAN device estimates and calibrates the pulse repetition interval (PRI) and delays between partial pulses to reconstruct the original radar pulses, correcting the impaired pulses to restore their full pulse width and uniform PRI, thereby enhancing radar detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WLAN devices operate in DFS channels to share frequency with radars, then channel utilization is improved, but radar detection accuracy deteriorates due to pulse width shortening and pulse repetition interval distortion caused by channel and filtering effects
Solution Approach 1:
The patent applies parameter changes by adjusting the pulse repetition interval parameter used for radar detection to account for the distortion caused by channel and filtering effects. Specifically, the system calculates a corrected PRI that compensates for the shortening effect, allowing accurate detection despite the impaired pulse characteristics. This resolves the contradiction by maintaining detection accuracy while operating in shared DFS channels.
2Device complexity
If shared receiver blocks are used to reduce device complexity and cost, then device complexity is reduced, but radar signal detection capability deteriorates due to filtering effects breaking pulses into multiple smaller pulses
Solution Approach 1:
The patent extracts and compensates for the specific distortion characteristics introduced by the shared receiver filtering effects. By identifying the pulse breaking phenomenon as a separate, quantifiable effect and developing a compensation mechanism, the system maintains reliable radar detection despite using cost-effective shared receiver blocks. This allows the system to benefit from reduced complexity while preserving detection capability.
3Reliability
If pulse combination software is used to reconstruct original pulse width, then detection capability is improved, but detection reliability deteriorates when pulses are delayed and narrowed beyond recognition thresholds
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the relationship between original pulse characteristics and impaired pulse characteristics under various channel conditions. Instead of attempting to reconstruct pulses after they are distorted, the system proactively adjusts detection parameters based on expected distortion patterns, enabling reliable detection even when pulses are significantly delayed and narrowed. This preventive approach overcomes the limitations of post-detection reconstruction methods.
Data Source
AI summary
Disclosed are methods and systems for a WLAN device operating on DFS channels to calibrate the PRI as well as delays between partial pulses of received radar pulses that are impaired due to channel and filtering effects. The calibrated PRI may approximate the PRI of the transmitted pulses. The calibrated delay between the partial pulses estimates the interval between two partial pulses that originally belong to the same transmitted pulse. Using the calibrated PRI and the calibrated delay between partial pulses, the WLAN device may reconstruct the original pulses from received impaired pulses even when the impaired pulses are delayed and partial pulses of the original pulses. The WLAN device may use the calibrated results to correct the shortened PW and varying PRI of the impaired pulses to restore the partial pulses to their full PW with a relatively uniform PRI, increasing the probability of detecting the radar signals.