Performance Analysis of RIS Assisted RSMA Communication System

This paper investigates a reconfigurable intelligent surface (RIS)-aided rate-splitting multiple access (RSMA) communication system. A base-station communicates with cell-edge users using the RSMA protocol with user-dedicated RIS. Using the univariate dimension reduction method, the expressions for the outage probability (OP) are derived considering the optimal and discrete phase-shifts introduced by RIS elements. The interdependent constraints of the threshold and the RSMA factors are derived and analyzed. Furthermore, the effects of various factors such as number of RIS elements, number of quantization bits, RSMA factors, threshold, etc. have been discussed and several interesting insights are presented. The derived expressions are validated using the Monte-Carlo simulations.