A Survey on Noma With the AId of Intelligent Reflecting Surface in Wireless Communication

Non-orthogonal multiple-access (NOMA) and its enhanced versions are potentially emerging technologies which contribute to boost the blossoming of the wireless signal propagation in the mobile and IoT era. In this paper, an overview of the NOMA communication mechanism with the aid of intelligent reflecting surface (IRS) is presented. The survey shows that the IRS-based NOMA allows communicating even in the areas with the weakest signals so that the NOMA-aided wireless designers can have an insight into improving the performance of wireless communication networks. In particular, a comparison of key characteristics of NOMA with IRSs and relays is also presented. In addition, the challenges and applications of this type of NOMA are also discussed. Besides, the formulas of the signals at the sources and destinations of background NOMA communication systems are also analyzed. This survey thus provides a background of IRS-employed NOMA for deeper studies of this technology.