Performance analysis of multiple-relay cognitive communication system in Rayleigh fading channel

Abstract

The spectrum scarcity in communication systems has attracted many researches in the area of cognitive communication which is known as a precious solution to overcome this problem. Overlay (OL) and underlay (UL) strategies are two main techniques in the cognitive systems (CSs). On the other side, cooperative communication improves the reliability and capacity of data communications when using the multiple-relay scheme. In this paper, assuming the multiple-relay cooperative cognitive communication system, the quality of service (QoS) parameters as effective capacity (EC) and outage probability (OP) are analyzed in details. A closed-form mathematical expression is obtained for OP and EC in Rayleigh fading channel considering different constraints on the CS such as false detection of busy/idle state of primary user (PU), or interference threshold of secondary user on PU in OL and UL strategies, respectively. Moreover, the comparison of OL and UL strategies in terms of the QoS parameters is done. As will be shown in this paper, simulation and numerical results verify each other and follow the mathematical analysis of the QoS parameters.

Outage analysis of cognitive communication system using opportunistic relay selection and secondary users as relays

“…Secondary rate maximization with considering the constraint of primary rate is presented in [19] subjected to the interference constraint and power constraint as the main conditions of optimization. Outage probability and effective capacity in overlay and underlay strategy are discussed for maximization of effective capacity and minimization of outage in [20]. Spectrum sharing in cognitive system considering multiple antennas in PU/SU transmitters is assumed in [21].…”