Throughput Characterization for Cooperative Wireless Information Transmission with RF Energy Harvesting-Based Relay

The simultaneous wireless information and power transfer (SWIPT) in a cooperative relaying system is investigated, where the relay node is self-sustained by harvesting radiofrequency (RF) energy from the source node. In this paper, we propose a time switching and power splitting (TSPS) protocol for the cooperative system with a mobile destination node. In the first part of the transmission slot, a portion of the received signal power is used for energy transfer, and the remaining power is used for information transmission from the source to the relay. For the remaining time of the transmission slot, information is transmitted fromthe relay to a mobile destination node. To coordinate the wireless information and power transfer, two transmission modes are investigated, namely, relay-assisted transmission mode and nonrelay mode, respectively. Under these two modes, the outage probability and the network throughput are characterized. By joint optimization of the power splitting and the time switching ratios, we further compare the network throughput under the two transmission modes with different parameters. Results indicate that the relay-assisted transmission mode significantly improves the throughput of the wireless network.