Hardware Radar Signal Detection in Wireless Access Points
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Solution Overview
Problem
Current wireless communications systems, such as those supporting the IEEE 802.11a standard, face challenges in detecting radar signals across various frequency bands, particularly in complying with stringent regulatory requirements like the FCC's Dynamic Frequency Selection (DFS) specification, which demands detection of three types of radar waveforms: time-invariant with fixed parameters, time-invariant with a range of parameters, and time-varying waveforms, often relying on software-implemented algorithms rather than hardware-based solutions.
Innovation Solution
A hardware-based system is developed to detect radar signals by processing raw energy detect signals to identify valid radar pulses within predetermined pulse width limits, using a combination of pulse detectors and frequency detectors with shift registers and logical OR gates to identify specific waveform types, enabling detection of all three specified waveform types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-implemented algorithms are used to detect radar signals, then the system can be implemented with existing communication hardware, but the detection reliability and precision are insufficient to meet stringent regulatory requirements
Solution Approach 1:
The patent replaces software-implemented radar detection algorithms with a hardware-based detection system consisting of pulse detectors, frequency detectors, and waveform type detectors. This substitution of mechanical/hardware systems for software solutions improves detection reliability and precision to meet stringent regulatory requirements while maintaining implementation feasibility.
Solution Approach 2:
The detection system is segmented into multiple specialized components: pulse detectors for detecting pulse signals, frequency detectors for analyzing frequency characteristics, and waveform type detectors for identifying specific radar waveform types. This segmentation allows each component to be optimized for its specific function, improving overall detection reliability.
2Measurement precision
If a hardware-based system is designed to detect all three types of radar waveforms specified by FCC DFS, then detection precision and reliability improve, but device complexity increases
Solution Approach 1:
The hardware-based detection system is designed with multi-functional capabilities to detect all three types of radar waveforms specified by FCC DFS: type 1 (time-invariant with fixed parameters), type 2 (time-invariant with range of parameters), and type 3 (time-varying). This universality allows a single system to meet comprehensive regulatory requirements without requiring multiple separate detection systems.
Solution Approach 2:
The detection system incorporates dynamic parameters detection capabilities, particularly for type 2 and type 3 waveforms where parameters such as pulse width and frequency can vary within specified ranges. The system dynamically adjusts detection thresholds and parameters to accurately identify waveforms with varying characteristics.
3Adaptability or versatility
If the system implements comprehensive radar detection to comply with multiple DFS specifications, then regulatory compliance improves, but false alarm rate increases
Solution Approach 1:
The detection system incorporates feedback mechanisms where detection results from pulse detectors, frequency detectors, and waveform type detectors are continuously analyzed and validated. The system uses feedback to adjust detection thresholds and confirm radar signal presence, reducing false alarms while maintaining comprehensive regulatory compliance across multiple DFS specifications.
Data Source
AI summary
A system and method for providing radar signal detection in a communications system. In an example method, a raw energy detect signal is received and analyzed to determine if the raw energy detect signal contains a valid radar pulse. A bit is stored in a bit sequence storage device such that the bit has a first value if a valid radar pulse was detected or a second value indicating that a valid pulse was not detected. A set of bits in the bit sequence storage device are accessed to determine if a plurality of waveform-indicating locations in the bit sequence storage device includes valid pulses. In another aspect of the invention, a system detects a radar signal in a communications device. The system includes a pulse detector to detect pulses in a raw energy signal having a pulse width within a predetermined minimum and maximum pulse width. The system includes a frequency detector having a bit sequence storage device to store the bits output by the pulse detector. The frequency detector detects whether the detected pulses conform to a waveform type by determining if the bits are stored in the bit sequence storage device in waveform-indicating locations.