Reconfigurable Intelligent Surfaces in Cooperative NOMA: A Review of Key Concepts and Applications

The purpose of this survey paper is to provide an overview of the different multiple access techniques, the reason for integrating Reconfigurable Intelligent Surfaces (RIS) with Cooperative Non-Orthogonal Multiple Access (C-NOMA) and the system model of RIS-aided C-NOMA with mathematical equations. The study discusses other 6G technologies and contributes to understanding how RIS-aided C-NOMA together with the other 6G technologies comes close to realizing the goals 6G wireless networks. The paper presents the real-world applications of RIS-aided C-NOMA along with challenges and possible solutions on which upcoming researchers can focus on.