A time-splitting cooperative spectrum sharing amplify-and-forward relaying protocol with energy harvesting cognitive user

Simultaneous wireless information and power transfer (SWIPT) in energy-constrained wireless sensor networks has attracted considerable attention from the research community due to its promising features in increasing the lifetime devices in addition to mitigate the environment hazards caused by using conventional cell batteries. On the other hand, the advancements in the areas of cooperative spectrum sharing protocols have enabled efficient use of spectrum band between primary and secondary users. Owing to this fact, in this paper, we consider an energy-constrained secondary user which harvests energy from the primary signal and forwards this latter with the guarantee of spectrum access. A time-splitting cooperative spectrum sharing (TS-CSS) at the amplify-and-forward relay is proposed. Assuming a Nakagami-m fading model, exact closed-form expressions for the outage probabilities of the primary and secondary users are derived. From the obtained results, it is shown that the secondary user can carry its own transmission without adversely effecting the performance of the primary user. Furthermore, the effect of various system parameters, such as splitting ratio, distance between nodes and harvesting efficiency, on the system outage performance of these protocols is investigated and several insights are drawn.