Relay based cooperative spectrum sensing in cognitive radio networks over rayleigh fading channel with path loss effects

In this paper, we tackle the issue of cooperative spectrum sensing in cognitive radio network with path loss effects. Cooperative relays are introduced between primary user and cognitive center. The deteriorating effect of path loss is evaluated by measuring the detection performance of energy detector employed in cognitive radio network. Both single relay and multiple relays regimes are employed. Two schemes for relay´s location in cognitive radio network are proposed and the impact of relay´s location between primary user and cognitive receiver is evaluated through cognitive center´s detection parameters i.e probability of false alarm and probability of detection. The receiver performance is analyzed for Rayleigh fading channels, independent and identically distributed. The path loss exponent is taken as 3 to show the degenerative radio environment. The detection performance has been greatly improved by increasing number of relays and locating the relays nearer to the primary user, whereas moving the relays away from primary user drastically decreases the probability of detection.