Radar Signal Detection via Pulse Repetition Interval Analysis
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Solution Overview
Problem
Existing U-NII devices face challenges in accurately distinguishing between radar signals and interfering signals, leading to incorrect channel changes and resource exhaustion due to high bit error rates and synchronization errors, especially with short pulse radar signals.
Innovation Solution
A method for real-time detection of short pulses radar signals involves collecting data until an End-Of-Burst condition is identified, processing it to determine the Pulse Repetition Interval, and checking for periodic patterns, with additional filtering to differentiate between radar and interfering signals, allowing for accurate channel changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar detection algorithms match predefined pulses to received signals, then radar signal identification can be achieved, but the system can only identify pre-described patterns and requires large computation for matching many radar patterns
Solution Approach 1:
The patent changes the detection parameters from matching complex predefined pulse patterns to measuring simple temporal characteristics (time intervals between synchronization errors). Instead of comparing received signals against a large database of radar pulse patterns, the system measures the time interval between consecutive synchronization errors and checks if it falls within a predetermined range, dramatically reducing computational complexity while maintaining detection accuracy
Solution Approach 2:
The patent extracts only the essential characteristic of radar signals (periodic time intervals between pulses) from the complex signal structure. By focusing solely on the temporal pattern rather than the complete signal waveform, the system achieves radar detection with minimal computation, extracting only the necessary information needed for identification
2Reliability
If U-NII devices cannot discriminate between radar pulses and interfering signals, then frequency channels are eliminated one by one, but this leads to resource exhaustion as interference-free channels do not practically exist
Solution Approach 1:
The patent uses feedback from multiple synchronization errors to distinguish radar signals from interference. Instead of reacting to a single synchronization error, the system collects multiple errors and analyzes their temporal pattern. The feedback mechanism compares the measured time interval against predetermined thresholds, enabling reliable discrimination that prevents false channel eliminations and preserves available frequency resources
3Difficulty of detecting and measuring
If U-NII hardware reports all high-energy signals without preambles as synchronization errors, then radar signals can be detected, but interfering signals from adjacent channels and other systems are also misidentified
Solution Approach 1:
The patent performs preliminary action by collecting multiple synchronization errors before making an identification decision. Instead of immediately classifying a single synchronization error as radar or interference, the system accumulates a series of errors and then analyzes their temporal relationships. This preliminary data collection phase enables accurate discrimination by establishing the periodic pattern characteristic of radar signals
Data Source
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AI summary
A method provides for identifying short radar signals in presence of interfering signals from various sources applicable to U-NII devices. The method includes collecting a set of information about received interfering signals until the End-Of-Burst (EOB) condition is identified. When the EOB is identified, the set information about the received train of interfering signals is processed. The algorithm selects the time interval between two pulses as a possible Pulse Repetition Interval (PRI) and checks if the same time interval or a multiple of it can be found between other pulses in the collected set, with some small acceptable error. Pulses matching the criteria are considered as potential radar pulses. When at least one pulse has been identified as a potential radar pulse for a number of times larger than a predefined limit, it is concluded that that pulse has been generated by a radar installation.