On the outage performance of SWIPT-NOMA-CRS with imperfect SIC and CSI

In this paper, a nonorthogonal multiple access based cooperative relaying system (NOMA-CRS) is considered to increase spectral efficiency. Besides, the simultaneous wireless information and power transfer (SWIPT) is proposed for the relay in NOMA-CRS. In SWIPT-NOMA-CRS, three different energy harvesting (EH) protocols, power sharing (PS), time sharing (TS) and ideal protocols are implemented. The outage performances of the SWIPT-NOMA-CRS are studied for all three EH protocols. In the analysis, to represent practical/reasonable scenarios, imperfect successive interference canceler (SIC) and imperfect channel state information (CSI) are taken into consideration. The derived outage probability (OP) expressions are validated via computer simulations. Besides, the OP for the benchmark scheme, NOMA-CRS without EH, is also derived under imperfect SIC and CSI. Based on extensive simulations, it is revealed that the SWIPT-NOMA-CRS outperforms NOMA-CRS without EH. Finally, the effects of all parameters on the outage performance of the SWIPT-NOMA-CRS are discussed and for the given scenarios, the optimum PS factor, TS factor and power allocation coefficients are demonstrated.