Performance of cooperative spectrum sensing over fading channels with low signal-to-noise ratio

Transmission error because of fading in the cognitive radio-fusion centre (CR-FC) links can severely degrade the performance of cooperative spectrum sensing. In this study, the upper and lower bounds of the overall false alarm probability and overall detection probability are derived as functions of the bit-error probabilities (BERs) of the CR-FC links. Based on these bounds, the constraints that the BERs of the CR-FC links should satisfy are addressed given the target overall false alarm probability or overall detection probability. Furthermore, channel coding schemes and cooperative schemes that provide reliable transmissions in the CR-FC links are studied. Particularly, inspired by the cluster-based cooperative spectrum sensing, a multiuser cooperative scheme is proposed. Finally, the relationship between the overall detection probability and the overall false alarm probability is investigated when the SNR of the primary user signal at each CR node is small.