Reconfigurable Intelligent Surface-Based Orbital Angular Momentum Communications Toward 6G

As the demand for higher channel capacity and lower energy consumption in the forthcoming sixth-generation (6G) era continues to increase, innovative solutions are paramount. In this article, an architecture based on reconfigurable intelligent surface (RIS) and orbital angular momentum (OAM) is proposed for increasing both channel capacity and energy efficiency. OAM can significantly enhance channel capacity through multiplexing, while RIS can reconfigure radio environments to reduce the system's energy consumption effectively. Unlike existing research on RIS at the transmitter in RIS-assisted OAM systems, the proposed RIS-OAM architecture offers a novel solution to the challenges of increased channel capacity and reduced power consumption in 6G networks. The generation, transmission, and reception of OAM signals are investigated. Simulations demonstrate that RIS-OAM communications can substantially improve both channel capacity and energy efficiency. Potential issues in practical applications of RIS-OAM communications are discussed, as well as future research directions and related technologies.