Hardware-Limited Cooperative SWIPT-enabled NOMA Networks

In this paper, the outage probability (OP) of a two-hop cooperative non-orthogonal multiple access (NOMA) network over Nakagami-m fading channels with an energy restricted relay is evaluated, while considering the hardware impairments at the network entities. Two energy-harvesting protocols, namely, power splitting relaying (PSR) and time-switching relaying (TSR), are considered. Analytical expressions for the outage probability (OP) are derived and Monte Carlo simulations are provided to validate the correctness of analysis. Obtained results highlight the importance of hardware impairments in the OP evaluation at the high signal-to-noise ratio regime. Moreover, the PSR demonstrates better performance than the TSR one. Finally, results reveal the benefit of the usage of cooperative NOMA reflected by significant improvement in the OP for both protocols.