Spectrum sensing with censoring of double threshold based cognitive radios in Rayleigh fading

In this paper, the performance of cooperative spectrum sensing (CSS) with censoring of cognitive radios (CRs) has been evaluated using a simple majority logic fusion in presence of Rayleigh fading affecting both the sensing (S) and reporting (R) channels. Each CR senses the primary user (PU) using a double threshold based energy detection over the sensing channel. Censoring of CRs is done on the basis of the quality of Rayleigh faded R-channel. Typically two types of censoring such as rank-based and threshold-based censoring are considered to select the best CR based on the quality of the R-channels between CRs and a fusion center (FC). The performance of CSS, in terms of average missed detection, is evaluated in terms of relevant network parameters such as; (i) number of selected CRs, (ii) censoring thresholds, (iii) fail sensing probabilities, (iv) S and R-channel signal to noise ratios (SNRs) under both the perfect and imperfect channel estimation. The performance in terms of agility gain, normalized average number of transmitted bits for different number of CRs is also studied. Further the performance of double threshold based energy detection is compared with that of single threshold based energy detection. Our studies demonstrate that censoring with double threshold outperforms the censoring with single threshold.