On Performance of Hybrid RIS-Aided NOMA Network

Reconfigurable intelligent surface (RIS) is considered a groundbreaking technology and an essential component of the 6th generation communications, owing to its inherent ability to control and optimize wireless channels. Recently, both active and passive RIS have been used together in hybrid form to achieve better performance with better power optimization. This paper analyzes the performance of a wireless communication system utilizing non-orthogonal multiple access (NOMA) for ultra-dense networks by a hybrid reconfigurable intelligent surface (HRIS), which leverages the hybrid RIS architecture that includes both the active and the passive reflecting elements (REs). For both the near-user and the far-user, a closed-form expression of the outage probability in Nakagami-<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$m$</tex> fading channels has been derived. Furthermore, performance of the considered network is compared with the traditional orthogonal multiple access (OMA) technique to showcase the advantage of NOMA over the OMA. The impact of severity, data rate, number of REs, and other system parameters on the outage performance of the considered networks are illustrated. Finally, Monte-Carlo simulations are conducted to corroborate the validity of derived closed-form expressions.