Performance Analysis of the Downlink NOMA EH Relaying Network with RTRI

In this paper, we analyze the performance of a non-orthogonal multiple access (NOMA) energy harvesting (EH) relaying system with the residual transmit RF impairments (RTRI) over a Rayleigh fading channel. Users in our proposed system are allocated with different power levels. The source node communicates with the near user using the direct link and communicates with the far user via an amplify-and-forward (AF) relay which uses the time-switching (TS) protocol to harvest energy from the source's signal. The near user also receives the signal broadcasted by the relay and uses this signal to improve its performance. To evaluate the performance of system, the expressions for outage probability (OP) and throughput are derived, and these analyses are verified by a Monte Carlo simulation. Moreover, the effects of various parameters, such as power allocation levels, target data rate, EH efficiency and transmit hardware impairment levels on the OP and throughput of proposed system are investigated.