Joint spectrum sensing and DOA estimation with sub-Nyquist sampling

Abstract

This paper addresses the problem of joint spectrum sensing and Direction-of-Arrival (DOA) estimation under array receiver based on modulated wideband converter (MWC) with sub-Nyquist sampling. To simplify the structure of MWC, we connect one identical branch of MWC on each antenna of array receiver, reducing the overhead of hardware resources. Two joint spectrum sensing and DOA estimation (JSS-DOA) algorithms, referred to as CP- and MUSIC-based algorithms, are proposed to improve the robustness of estimation. The proposed approaches utilize Fourier series coefficients of a periodic signal provided by MWC to determine the subband positions where sources are located, and combine the recovered subband spectrum information to obtain estimates of frequencies. This strategy ensures robust frequency estimation accuracy under certain conditions and contributes to a robust DOA estimation under high noise level. We further provide a theoretical analysis of the working conditions for proposed algorithms, based on which the rationale of parameter setting is also reported. Finally, the performance of proposed algorithms is assessed via simulation experiments concerning multiple unknown sources under our receiver with sub-Nyquist sampling.