Cognitive Radio Relay Networks with Simultaneous Wireless Information and Power Transfer and Multiple Secondary Destinations

In this research work, we will study the performance of simultaneous wireless information and power transfer (SWIPT) technique in a multi-destination dual-hop underlay cognitive relay network with multiple primary receivers. Information transmission from the secondary source to secondary destinations can be performed via a decode-and-forward (DF) relay. The relay node is assumed to have no embedded power source and to harvest energy from the source signal using a power splitting (PS) protocol and employing opportunistic scheduling to forward the information to the selected destination. Another important scenario in cognitive DF relay networks is the scenario with incremental relaying. Incremental relaying has attracted research attention as it minimizes the relay usage and improves the spectral efficiency of the relaying system. In this scenario, the secondary source can communicate with the selected secondary destination via a direct link and the relay forwards the message to the selected destination only when the direct link has been failed. We will derive analytical expressions for the outage probability assuming the channels gain follow the Rayleigh fading channel and considering the energy harvesting efficiency at relay, the source maximum transmit power and primary receivers interference constraints. The system performance will be studied at high signal-to-noise ratio (SNR) regime where the outage probability will be approximated and analyzed in terms of coding gain and diversity order. Monte-Carlo simulations and some practical numerical examples will be provided to validate the obtained expressions and to illustrate the effect of various system parameters on the performance of the system. To be more comprehensive and depending on the tractability of the achieved expressions, the effect of the interference on the system performance will be considered in this research work. The derived results are expected to provide a deep insight to the effect of number of secondary destinations, number of primary receivers, and the distance between the relay and destinations on the performance of the system.