Array-Based Compressed Sensing Receiver Architecture for Wideband Spectrum
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Solution Overview
Problem
Current spectral sensing systems are inefficient in utilizing wide bandwidths, often missing short-lived signals due to sequential hopping across narrow spectral bands, and have high size, weight, and power (SWAP) requirements due to bulky instantaneous frequency measurement (IFM) receivers.
Innovation Solution
The use of array-based compressed sensing techniques with multiple antennas and analog-to-digital converters (ADCs) operating at sub-Nyquist sampling rates to generate aliased signals, allowing for wideband spectrum sensing with lower SWAP through the sparse fast Fourier transform (sFFT) and coherent combining of signals for direction-of-arrival estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sequential hopping across narrow spectral bands is used, then system complexity is reduced, but detection capability deteriorates due to missing short-lived signals in wide bandwidths
Solution Approach 1:
The wideband spectrum sensing problem is segmented into multiple narrowband sub-bands that can be processed independently. Each sub-band is sensed separately and then combined to form the complete wideband spectrum picture, allowing detection of short-lived signals across the entire bandwidth while maintaining manageable system complexity
Solution Approach 2:
The patent transforms the single-dimensional sequential frequency hopping approach into a multi-dimensional parallel processing architecture. Multiple antennas and ADCs operate simultaneously on different sub-bands, converting a time-sequential operation into a spatial-parallel operation that captures wideband signals without missing transient events
2Measurement precision
If IFM receivers are used for spectral sensing, then detection precision is improved, but SWAP (size, weight, power) increases significantly
Solution Approach 1:
The patent extracts only the essential sensing function from the bulky IFM receiver architecture. By using simple ADCs to capture digital samples directly and processing these samples through spectrum estimation algorithms, the system achieves comparable detection precision without the heavy hardware overhead of traditional IFM receivers
Solution Approach 2:
The patent replaces the mechanical/electronic IFM receiver system with a digital signal processing-based approach. Instead of using hardware frequency measurement circuits, the system uses software-based spectrum estimation algorithms to achieve the same detection precision with dramatically reduced SWAP
3Weight of moving object
If multiple ADCs operating at sub-Nyquist rates are used, then SWAP is reduced, but signal reconstruction accuracy may deteriorate due to aliasing
Solution Approach 1:
The patent converts the harmful aliasing effect into a beneficial tool for signal reconstruction. By deliberately sampling at sub-Nyquist rates and allowing controlled aliasing to occur, the system creates a unique aliasing pattern that can be used to identify and reconstruct the original signal frequencies through spectrum estimation algorithms
Solution Approach 2:
The system uses iterative feedback-based spectrum estimation algorithms that refine the signal reconstruction by comparing the reconstructed spectrum with the observed aliased samples. This feedback loop continuously improves the accuracy of frequency and power estimates until convergence is achieved
Data Source
AI summary
An array-based Compressed sensing Receiver Architecture (ACRA) includes an antenna array with two or more antennas connected to two or more ADCs that are clocked at two or more different sampling rates below the Nyquist rate of the incident signals. Comparison of the individual aliased outputs of the ADCs allows for estimation of signal component characteristics, including signal bandwidth, center frequency, and direction-of-arrival (DoA). Multiple digital signal processing (DSP) techniques, such as sparse fast Fourier transform (sFFT), can be employed depending on the type of detection or estimation.