Energy harvesting in hybrid two-way relaying with direct link under Nakagami-m fading

Abstract

In this paper, we examine the performance of simultaneous wireless information and power transfer (SWIPT) in the two-way relay networks under Nakagami-m fading. We consider a three-node wireless communications system, where two source nodes communicate to each other via a half-duplex battery-enabled relay node. A hybrid decode-amplify-forward (HDAF) based relaying scheme is proposed to make the communication links more reliable. With this scheme, the relay node can harvest energy from the radio-frequency (RF) signals, and destination nodes can exploit the direct link. For harvesting energy from RF signals, we adopt time switching (TS) approach, whereby relay node first harvests energy from the received signals in the first phase (energy harvesting phase), and then utilizes the harvested energy to process and broadcast the received signals in next three consecutive (information processing) phases. At the destination nodes, selection combining (SC) technique is employed to make use of two intended signals received via direct and relay links. For this setup, we derive the closed-form expressions for user outage probability (OP) and achievable system throughput under Nakagami-m fading. Numerical and simulation results are provided to highlight the impact of various system and channel parameters on the SWIPT-enabled wireless system and to verify the accuracy of derived expressions. © 2018 IEEE.