Performance Analysis for SWIPT Based Cooperative Non-orthogonal Multiple Access With Two Phase Superposition Transmission

Abstract

In this paper, we propose a cooperative nonorthogonal multiple access (NOMA) network with simultaneous wireless information and power transfer (SWIPT) technology, where the two-phase superposition coding is employed to improve the performance of NOMA relaying network. In the first phase, the source will simultaneously transmit two symbols using superposition coding, while the relay decodes the symbols via adopting successive interference cancellation and harvests energy from radio frequency (RF) signals through employing power splitting (PS) protocol. In the second phase, the relay redistributes the harvested energy to forward signals with a new superposition coding to the destination. The analytical expressions for decoding the two signals on outage probability are derived, respectively. Besides, we premeditate that the ratio of power allocation ratio (RPAR)1 in the two-phase superposition transmission network and the optimal RPAP is delivered by combining computer simulations and analysis. Computer simulations verify the existence of optimal RPAP and our findings, as well as to demonstrate the superiority of the proposed scheme in terms of outage probability and system throughput by comparing it with the existing scheme.