Outage performance of cognitive cooperative networks with relay selection over double-Rayleigh fading channels

This study considers a dual-hop cognitive inter-vehicular relay-assisted communication system where all<br/>communication links are non-line of sight ones and their fading is modelled by the double Rayleigh fading distribution.<br/>Road-side relays (or access points) implementing the decode-and-forward relaying protocol are employed and one of<br/>them is selected according to a predetermined policy to enable communication between vehicles. The performance of<br/>the considered cognitive cooperative system is investigated for Kth best partial and full relay selection (RS) as well as<br/>for two distinct fading scenarios. In the first scenario, all channels are double Rayleigh distributed. In the second<br/>scenario, only the secondary source to relay and relay to destination channels are considered to be subject to double<br/>Rayleigh fading whereas, channels between the secondary transmitters and the primary user are modelled by the<br/>Rayleigh distribution. Exact and approximate expressions for the outage probability performance for all considered RS<br/>policies and fading scenarios are presented. In addition to the analytical results, complementary computer simulated<br/>performance evaluation results have been obtained by means of Monte Carlo simulations. The perfect match between<br/>these two sets of results has verified the accuracy of the proposed mathematical analysis.