Wireless Information and Power Transfer in Cooperative Communications with Power Splitting

In this paper, we consider a cooperative communication system, where the relay node is capable of simultaneous wireless information and power transfer (SWIPT) by splitting the signal from the source node into two power streams for energy harvesting and information relaying, and study the optimal design to maximize the cooperative capacity for both amplify-and-forward (AF) and decode-and-forward (DF) protocols. The closed-form optimal power-split ratio is derived for the two protocols with in-depth analysis and performance in cooperative capacity is evaluated for the optimal power splitting scheme with AF and DF protocols. Experiment results show that AF protocol benefits more from favorable cooperation link condition than the DF protocol and cooperation link condition contributes more to the optimal cooperative capacity compared with direct link condition. Asymptotic analysis also show that signal processing noise is also non-negligible to the optimal cooperative capacity.