Threshold Based Censoring of Cognitive Radios in Rician Fading Channel

This paper describes about the performance analysis and comparison between hard decision (majority rule) logic and soft decision (maximal ratio combining) logic approaches using cooperative spectrum sensing (CSS) with censoring scheme. We have considered both sensing channel (S-channel) and reporting channel (R-channel) are affected by Rician fading. Radio links present in the channel gets heavily faded and the information received at the fusion center (FC) becomes erroneous because of fading effect present in the channel. Threshold based censoring scheme is used to eliminate the heavily faded cognitive radios (CRs) in R-channel. Two fusion rules namely, majority logic and maximal ratio combining (MRC) are considered individually at the fusion center to estimate the performance of CSS by censoring of R-channel links. The performance is evaluated in terms of missed detection probability (Qm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q_{m}$$\end{document}) and total error probability (Qm+Qf\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q_{m} + Q_{f}$$\end{document}) in both majority logic and MRC logic. Comparison table between perfect and imperfect channels is provided to know which fusion rule (MRC, majority) performs better under Rician fading. Simulations are performed under both perfect and imperfect channels by varying the network parameters like probability of false alarm (Pf\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P_{f}$$\end{document}), S-channel SNR, R-channel SNR, Rician fading parameter (K) and number of CR users (N).