Jettison the Defectives: A Robust Cooperative Spectrum Sensing Scheme in a Cognitive Radio Network

In this paper, we extenuate the effect of malicious cognitive sensors (MCSs) from the optimal combining of cooperative spectrum sensing scheme. We consider the cognitive radio network (CRN) that includes honest cognitive sensors (HCS) and MCSs; the former one, report accurate sensing data to the combining centre (CC), while the latter, due to its malfunctioning, reports CC a false data of dissimilar statistical distribution. Our sensing scheme includes the combined two-stage test at CC, namely Shapiro–Wilk’s normality test and log-likelihood ratio test. The former is used to identify MCS and to exclude them from the latter, which optimally combines the sensing information of HCS. Simulation results show that detection performance of proposed method bests fault-tolerant cooperative spectrum sensing (FTCSS) method by 44.9%, when 4 MCS exist in a CRN. Further, the receiver operating characteristics show that, the proposed method does not increase the event of false alarm, unlike equal gain combining scheme and FTCSS, when MCS increases the false alarm.