Waveform-Triggered Reception for Millimeter-Wave SDRs
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Solution Overview
Problem
The challenge in millimeter-wave (mmWave) software-defined radios (SDRs) is the large difference between the sample rate of analog-to-digital converters and the processing speed of the companion computer, making it difficult to detect transmitted signals quickly and efficiently, especially in real-world environments, and existing solutions are often costly and not portable.
Innovation Solution
The implementation of waveform-triggered reception (WTR) and a buffer mechanism to support discontinuous transmissions, allowing the detection of a special trigger waveform to acquire IQ data samples and store them in a discontinuous manner, reducing the computational burden and enabling flexible companion computer-based baseband signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sample rate of the analog-to-digital converter is increased to capture mmWave signals quickly, then the signal acquisition speed is improved, but the processing speed requirement of the companion computer increases significantly
Solution Approach 1:
The patent segments the signal processing task by introducing a trigger waveform detection mechanism that operates independently at high speed, while the companion computer only processes signals after trigger detection. This divides the processing burden between the SDR hardware (trigger detection) and the companion computer (signal analysis), resolving the contradiction between high sample rate acquisition and processing speed requirements.
Solution Approach 2:
The patent implements preliminary trigger waveform detection before the companion computer needs to process the actual signal data. By detecting the trigger waveform and generating a triggering signal in advance, the system prepares the data structure and timing information beforehand, allowing the companion computer to process signals more efficiently without being bottlenecked by the high sample rate.
2Reliability
If continuous monitoring of signals is implemented at the companion computer, then signal detection completeness is improved, but the computational burden increases significantly
Solution Approach 1:
Instead of continuous monitoring, the patent implements periodic action through trigger-waveform-based interruption. The companion computer continuously monitors for the presence of the trigger waveform, and only when detected does it begin processing the actual signal data. This periodic activation pattern maintains detection completeness while dramatically reducing the computational burden compared to continuous processing.
Solution Approach 2:
The patent establishes a feedback mechanism where the trigger waveform detection result feeds back into the signal processing decision. The triggering signal generated from trigger detection provides feedback information that controls whether and when the companion computer should process signals, enabling reliable detection while avoiding unnecessary computational operations during non-trigger periods.
3Speed
If fast signal processing at the companion computer is implemented, then signal detection speed is improved, but the cost and complexity of the system increases
Solution Approach 1:
The patent extracts the high-speed trigger waveform detection function from the companion computer and implements it directly in the SDR hardware. By taking out this critical high-speed function and placing it in the SDR's digital signal processor, the system achieves fast signal detection without requiring the expensive and complex high-performance computer that would be needed if all processing were done at the companion computer.
Data Source
AI summary
The disclosure deals with methodology and system subject matter for a low-cost and portable millimeter-wave software-defined radio (SDR) which supports wireless experimentation in the 60 GHz band. The SDR uses a homodyne transceiver and provides a Transmission Control Protocol/Internet Protocol (TCP/IP)-based interface for companion computer (CC)-based baseband signal processing. To address the large difference between the processing speed of the CC and the sample rate of analog-to-digital converters, we use a disclosed method, called waveform-triggered reception (WTR), where a hard-coded block detects a special trigger waveform to acquire a predetermined number of in-phase/quadrature (IQ) data samples upon the detection. A buffer mechanism is used to support discontinuous transmissions. Using both the WTR and discontinuous transmissions, we can conduct a beam sweeping experiment, to evaluate 4096 beam pairs rapidly without compromising the flexibility of the CC-based processing.