Detection probability analysis for AF assisted cooperative spectrum sensing in cognitive radio networks

In this paper, we investigate the cooperative spectrum sensing when primary user data is forwarded to fusion center with the help of amplify-forward (AF) based cognitive relay in cognitive radio networks. We proceed by obtaining the probability density function (PDF) statistics of the received signal via AF relay link at the fusion center. Then we obtain the PDF of combined signal from relay link and direct link at the output of maximum ratio combiner (MRC). Finally, to avoid cumbersome integrations, we use an alternative representation of generalized marcum Q-function to obtain an upper bound for the detection probability when the network is operating over independent and identically distributed (IID) rayleigh fading channels. We also obtain an exact expression for detection probability when no cooperation is taking place among cognitive users. In the end, we present simulation results and compare them with the analytical expressions for the validity of our mathematical derivations.