Performance analysis of non-orthogonal multiple access assisted cooperative relay system with channel estimation errors and imperfect successive interference cancellation

This article studies a new non-orthogonal multiple access (NOMA) assisted decode-and-forward cooperative relay (NOMA-DFCR) system, where the downlink NOMA principle is employed to communicate between a source-destination pair through a dedicated relay. Performance of the proposed system is analyzed in terms of the outage probability (OP), system throughput (ST), and ergodic sum rate with channel estimation errors (CEEs) and imperfect successive interference cancellation (SIC). An approximate expression of the OP and the diversity order of the presented scheme are derived. To gain further insights, asymptotic analysis of the OP is carried out at high signal-to-noise ratio (SNR) regime. Further, we also investigate the impact of power allocation coefficients and CEEs on the system performance. Moreover, the OP of orthogonal multiple access (OMA) assisted cooperative relay system is evaluated and compared with the proposed scheme. To validate the correctness of the derived analytical results, Monte Carlo simulations are performed. Numerical and simulation results have shown that the proposed system outperforms its OMA counterpart and the schemes in References 14 and 15, in terms of both the ST and OP.