Joint impact of CEE and IQI on NOMA with full-duplex relaying system

This paper considers the performance of non-orthogonal multiple-access (NOMA) with full-duplex (FD) relaying system in the presence of two practical undesirable defects, namely channel estimation error (CEE) and in-phase/quadrature-phase imbalance (IQI). Specifically, in the proposed NOMA with FD relaying system, the exact expressions of outage probability (OP) for the considered two users have been derived firstly. Then, the corresponding optimal power allocation coefficients for minimizing the OP of the dual users are obtained. Finally, the approximate expression of the ergodic sum rate (ESR) for the system is presented. Simulation results demonstrate that: (1) NOMA with FD relaying system can achieve superior outage performance in comparison with NOMA with Half-duplex (HD) relaying system at low Signal-to-noise ratio (SNR), but the circumstance is exactly the opposite at high SNR; (2) IQI and CEE would result in performance degradation, and must be seriously considered while designing NOMA with FD relaying systems.