One-Bit Spectrum Sensing Peculiarities

The use of autonomous sensors for analyzing wide bands of radio frequency spectrum requires using the high-speed analog-to-digital converters (ADC). The operation of such devices with high bit resolution requires several watts of power. One-bit ADC will reduce power consumption and simplify the analog part of the receiver. The goal of the research is to determine the features and conditions under which it is advisable to analyze the radio frequency spectrum in a sophisticated radio electronic environment using a one-bit ADC. The problem of using such ADC is the deterioration of the signal-to-noise ratio (SNR) and the occurrence of spurious spectral components at its’ medium and high values. The task of spectrum sensing is complicated by the fact that a large number of signals with different values of bandwidth and SNR can be simultaneously present in the analyzed frequency band. After a one-bit ADC, the energy of the complex signal remains unchanged regardless of its shape. Therefore, at high SNR values, the signal energy flows into spurious spectral components. When the bandwidth of the signal increases to 30% of analyzed frequency range and higher, the spurious spectral components are transformed into a broadband pedestal. Analytical dependencies have been obtained that allow us to calculate the values of the SNR at which signals can be detected and spurious spectral components appear. These dependencies take into account the parameters of the Welch periodogram and the level of spectrum occupancy. The results of the analysis of real signals showed that the shape of the signal spectrum after one-bit ADC repeats the shape of the spectrum after an 8-bit ADC, except for the absence of some weak signals. The cost for simplified hardware implementation and lower power consumption when using one-bit ADC compared to ADC with higher resolution is a narrowing of the dynamic range of signals. The use of one-bit ADC for spectrum sensing will be justified only when there is information on the analyzed bandwidth occupancy and the SNR of the signals that can be observed.