Energy-Efficient Full-Duplex Cooperative Nonorthogonal Multiple Access

Abstract

<p>Full-duplex (FD) cooperative non-orthogonal multiple access (NOMA) achieves superior throughput over conventional half-duplex (HD) cooperative NOMA, where the strong users (SUs) with good channel conditions can act as an FD relay node for the weak users (WUs) with poor channel conditions. However, the energy efficiency (EE) of cooperative NOMA may be degraded due to additional power consumption incurred at the SUs. We are therefore motivated to investigate the EE maximization problem of an FD cooperative NOMA system. More importantly, we investigate the &amp;#x201C;signal-to-inference-noise ratio (SINR) gap reversal&amp;#x201D; problem of cooperative NOMA systems, which imposes successive interference cancellation (SIC) performance degradation at the SUs. This problem has not been documented in the exiting cooperative NOMA literature. A low-complexity algorithm is proposed for maximizing the system&amp;#x0027;s EE while guaranteeing successful SIC operation. Our numerical results show that the proposed algorithm achieves both higher EE and throughput over the existing HD cooperative NOMA and non-adaptive FD cooperative NOMA. More importantly, the proposed scheme guarantees a successful SIC operation at the SUs.</p>