On the performance of cooperative cognitive networks with proactive relay selection

This paper provides a general outage analysis framework for cooperative cognitive networks with proactive relay selection over non-identical Rayleigh fading channels and under both maximum transmit power and interference power constraints. We firstly propose an exact closed-form outage probability expression, which is then exploited for determining the diversity order and coding gain for proactive relay selection scenarios as well as deriving system performance limits at either large maximum transmit power or large maximum interference power. The derived performance metrics bring several insights into system performance behavior without the need of time-consuming Monte-Carlo simulations. Various results confirm the validity of the proposed derivations and show that cooperative cognitive networks with proactive relay selection incur performance saturation and their performance depends considerably on the number of involved relays. In addition, cooperative cognitive networks are significantly better than dual-hop counterparts without any cost of system resources.