On the performance of regenerative relaying for SWIPT in NOMA Systems

As a potential access strategy in 5G mobile communication systems, non-orthogonal multiple access (NOMA) has been proposed as a supplement to the traditional orthogonal multiple access (OMA). This paper investigates simultaneous wireless information and power transfer (SWIPT) in a NOMA relaying system. The data is transferred from a source to two end terminals among which the one close to the source acts as a relay employing decode-and-forward protocol to assist the far-end one. In order to simultaneously harvest the energy and information processing at relay node, power-splitting relaying (PSR) and time switching-based relaying (TSR) protocols are sequentially considered. Outage probability and ergodic rate of both protocols are firstly analyzed to realize the impacts of various parameters including energy harvesting time, power splitting ratio, energy harvesting efficiency, source data rate, and the distance between the source and the relay node. Numerical results are then provided to validate the analytical findings. It is shown that the PSR outperforms the TSR at normal SNR regime in terms of throughput and ergodic rate.