UWB Demodulator Using Delayed Correlation for PPM and Bi-phase Signals
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Solution Overview
Problem
Current UWB demodulation schemes face challenges in simultaneously demodulating PPM and bi-phase modulation, and are susceptible to interference from other wireless communication systems, while also requiring complex high-speed circuitry for accurate impulse waveform generation, which hinders low power consumption and cost-effective IC fabrication.
Innovation Solution
A UWB demodulating apparatus that employs multiple delayed-detecting sections to correlate reception signals with varying delay times, allowing for simultaneous demodulation of PPM and bi-phase modulation, and incorporates a simplified circuit arrangement suitable for IC fabrication, reducing power consumption and interference resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a template waveform generating section is used to generate exact impulse waveform at nanosecond order, then demodulation accuracy is improved, but circuit complexity and power consumption increase significantly
Solution Approach 1:
The invention divides the demodulation process into multiple parallel detection sections, each handling specific delay intervals. Instead of generating a complete template waveform, the system segments the correlation detection into three independent delayed-detecting sections that operate simultaneously, simplifying each individual section while maintaining overall accuracy.
Solution Approach 2:
The invention creates simplified copies of the reception signal at different delay intervals (T+τ, T, T-τ) rather than generating a complex template waveform. Each delayed version serves as a simplified reference for correlation detection, eliminating the need for high-speed impulse waveform generation while preserving demodulation capability.
2Adaptability or versatility
If a template-based correlation demodulation scheme is used, then PPM modulation demodulation is achieved, but bi-phase modulation demodulation cannot be performed simultaneously
Solution Approach 1:
The invention designs a universal demodulation structure that can handle both PPM and bi-phase modulations simultaneously. The three delayed-detecting sections with delay intervals of T+τ, T, and T-τ serve dual purposes: detecting PPM modulation through pulse position variation and bi-phase modulation through signal polarity changes, making the system multi-functional without requiring separate demodulation paths.
Solution Approach 2:
The invention makes the demodulation system dynamic by adjusting the interpretation of detection results based on the modulation type. The same hardware structure adapts its detection logic dynamically - for PPM, it detects pulse position shifts across delay sections; for bi-phase, it detects polarity changes in the delayed signals, allowing flexible adaptation to different modulation schemes.
3Productivity
If conventional UWB demodulation is used, then high-speed communication is achieved, but resistance to interference from other wireless systems is reduced
Solution Approach 1:
The invention converts the potential harm of interference into a benefit by using delayed detection. The correlation-based delayed-detecting sections inherently filter out uncorrelated interference signals while amplifying the desired UWB signal through constructive correlation. The delay intervals are specifically chosen to align with the impulse structure of legitimate UWB signals, causing interference to be rejected naturally.
Solution Approach 2:
The invention implements implicit feedback through the correlation detection process. The delayed-detecting sections continuously correlate the received signal with delayed versions, and the demodulating section integrates these detection results. This feedback mechanism reinforces the detection of valid UWB signals while suppressing interference, improving signal-to-noise ratio without reducing communication speed.
Data Source
AI summary
A demodulated signal is to be generated by use of a first detection signal detected a presence/absence of a signal according to a correlation between a reception signal PPM-modulated at a pulse interval of T and a pulse variation width of τ and the reception signal delayed with a time (T+τ), a second detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T), and a third detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T−τ). By thus combining a plurality of delayed detections, it is possible to obtain a UWB demodulating apparatus configured with a circuit suited for integrated circuit fabrication.