Blind Spectrum Sensing Using Antenna Arrays and Path Correlation

In this paper, we consider the problem of spectrum sensing in cognitive radios (CRs) when the receiver of the secondary user (SU) is equipped with a multiantenna system. Using an estimate of the cross correlation among the signals received at different antenna elements, we propose a blind detection method, which assumes no prior knowledge of the signaling scheme used by the PU, the noise power, or the channel path coefficients. The cross correlation among the received signals is a result of the correlation among the channel path coefficients from the primary user (PU) transmitter to different antenna elements of the secondary receiver. The detection and false alarm probabilities of the proposed algorithms are evaluated using an asymptotic analysis, and the results are compared with simulation results. It is shown that the proposed methods outperform several recently proposed blind-sensing techniques for CRs using multiple antennas.