Performance analysis of RIS aided NOMA networks with hardware impairments

Reconfigurable intelligent surface (RIS) has stimulated their potential applications for improving the performance of wireless communication networks. In this paper, the performance of RIS aided non-orthogonal multiple access (NOMA) networks with hardware impairments over Rician fading channels is investigated. More specifically, the exact and asymptotic expressions of outage probability for a pair of users, that is, the nearby user n and distant user m are derived, where the imperfect successive interference cancellation (ipSIC) and perfect SIC (pSIC) are taken into consideration. According to the approximate analyses, the diversity orders of user n with ipSIC/pSIC and user m are obtained in the high signal-to-noise radio regime. It indicates that the diversity orders are in connection with reflecting elements and Rician factors except the channel ordering. The impact of these parameters on outage behaviors of RIS-NOMA networks is also analysed. In addition, the system throughput of RIS-NOMA networks with ipSIC/pSIC is surveyed in detail. Monte Carlo simulations are present to verify the correctness of theoretical analyses that: (1) The outage probability of user n with pSIC is superior to that of orthogonal user, while the outage probability of user m is inferior to that of orthogonal user and (2) as the number of reflecting elements and Rician factors increases, the outage behaviors of RIS-NOMA networks are enhanced carefully.