Optimal Throughput of the ANC based Two-way Relay System with Energy Harvesting

This paper investigates the throughput performance of a two-way energy harvesting (EH) relaying system with analog network coding (ANC) scheme. ANC scheme can improve the transmission efficiency of the two-way relay network. Energy harvest is an emerging solution for prolonging the lifetime of wireless node by availing the ambient RF signals. In particular, we focus on the energy harvesting system with the time switching-based relaying (TSR) protocol. We successfully derive the analytical expressions for both the outage probability and the achievable throughput. The analytical result matches with the practical system throughput well. Furthermore, we derive a closed-form approximation of throughput and show that it is a log-concave function of the time-switching (TS) ratio. Therefore, the system throughput optimization can be mathematically formulated as a quasi-convex optimization problem which can be solved efficiently. Simulation results show that the closed-form expression of throughput is log-concave and the gap between the approximated throughput with the practical optimal throughout is less than 10%.