Performance of MRC fusion-based cooperative spectrum sensing with censoring of cognitive radios in rayleigh fading channels

In this paper, the performance of a cooperative spectrum sensing (CSS) is evaluated, considering maximal ratio combining (MRC) fusion in the presence of Rayleigh fading. A cognitive radio (CR) senses the primary users (PUs) using an energy detector (ED) in the sensing channel (S-channel). If a CR is selected to transmit its local decisions to a fusion centre (FC), it does so using a reporting (R)-channel with binary phase shift keying (BPSK) signaling. In the present work, we consider censoring of CRs based on a characterization of Rayleigh faded R-channels. In other words, CRs, whose estimated R-channel fading coefficients towards the FC exceed a predefined threshold (censoring threshold), are allowed to transmit. MRC fusion is considered at the FC to estimate the performance in terms of average missed detection and total error probabilities for various values of (i) the censoring threshold, (ii) the number of CRs, (iii) the average S-channel and R-channel signal-to-noise ratios (SNRs), under both perfect and imperfect channel estimations. The performance of CSS system with MRC fusion is also compared, for various values of the network parameters, with the performance with majority logic fusion.