Simultaneous Wireless Information and Power Transfer Strategies in Relaying Network With Direct Link to Maximize Throughput

In this paper, we investigate the optimal throughput performance for simultaneous wireless information and power transfer relaying network in the presence of direct link between the source and the destination. By considering the direct link, system performance can be improved when the channel condition is good from source to destination. The cooperative network consists of a source, an amplify-and-forward relay, and a destination, where the relay harvests energy from the source and then uses the harvested energy to forward information to the destination. At the destination node, the signals from the direct link and relay are combined by the maximum ratio combining (MRC) method. The time switching (TS) relaying protocol is applied to enable energy harvesting and information processing simultaneously. At the same time, we made progress on analyzing the throughput of information transmission on the basis of the MRC method with power switching (PS) relaying protocol. Additionally, adaptive-MRC protocol is proposed based on the TS and PS relaying protocols, which can choose better mode to achieve the communication. The numerical analyses provide practical insights into the effect of various system parameters, such as energy harvesting time splitting ratio, source transmission rate, distance between nodes, and noise power at the destination and the relay.