Linear Hard Decision Combining for Cooperative Spectrum Sensing in Cognitive Radio Systems

In this paper, we propose a new cooperative spectrum sensing scheme to minimize the false alarm probability while satisfying the detection probability at a desired level. To improve the spectrum sensing performance, it is desirable for the cognitive base station to combine binary local decisions of secondary users by considering the local sensing reliability. In the proposed scheme, the local decisions are combined with weighting factors that reflect the local sensing reliability of each secondary user to optimize the probability distribution function of the test statistic. The detection and false alarm probabilities are also analytically determined in closed form. Finally, the performance of the proposed scheme is verified by computer simulation.