Centralized cooperative spectrum sensing with multiple antennas over imperfect feedback channels

In this paper, we study the performance of a cooperative spectrum sensing (CSS) scheme over imperfect feedback channels, where N secondary users (SUs) collaborate in order to enhance the detection probability of a primary user (PU). The sensing process is divided into two phases: In the first phase each SU, which is equipped with multiple antennas, independently detect the PU signal. In the second phase, the SUs´ local decisions are sent via erroneous and orthogonal feedback channels to a fusion center (FC), where a final decision is made. We utilize Bayesian criterion which accounts for the costs of misdetection and false alarm. Quasi-Newton method is employed to obtain the optimal number of antennas for a given SNR and vice versa. Our simulation results concur the mathematical derivations and validate the optimality of quasi-Newton method. We further show that the derived optimal fusion rule outperforms the OR rule, AND rule and MAJORITY rule.