Outage Performance of Active RIS in NOMA Networks over Nakagami-m Fading Channels

This paper investigates the performance of active reconfigurable intelligent surface (ARIS) assisted non-orthogonal multiple access (NOMA) networks over cascaded Nakagami-m fading channels. The effects of hardware impairments (HIS) and the number of reflection elements on ARIS-NOMA networks with imperfect successive interference cancellation (ipSIC) and perfect successive interference cancellation (pSIC) are considered. More specifically, we derive the expressions of outage probability with ipSIC/pSIC for ARIS-NOMA-HIS networks. According to the approximated analyses, the diversity orders and high signal-to-noise ratio (SNR) slopes for a pair of non-orthogonal users are attained in detail. The simulation results are presented to verify that the outage behaviors of ARIS-NOMA-HIS networks precede that of ARIS-aided orthogonal multiple access (OMA), passive reconfigurable intelligent surface (PRIS) aided OMA, and other conventional cooperative communication.