Reconfigurable Intelligent Surface Based Orbital Angular Momentum: Architecture, Opportunities, and Challenges
Zhaohui Yang, Ye Hu, Zhaoyang Zhang, Wei Xu, Caijun Zhong, Kai‐Kit Wong
Abstract
Orbital angular momentum (OAM) has gained a lot of attention due to its potential in enhancing the spectral efficiency for wireless communications. Using different OAM modes, multiple independent data streams are simultaneously transmitted by using spatial distribution of helical phase, which enables OAM as a new form of multiple access technique for wireless communications. Controlling the phases of incoming electromagnetic waves, the reconfigurable intelligent surface (RIS) is suitable for implementing OAM. In this article, an RIS-based OAM framework is introduced. The basic concepts and features of RIS and OAM are presented. Then classifications and comparisons of different RIS-based OAM schemes are summarized. Simulation results verify that RIS-based OAM transmission can achieve nearly 100 percent higher spectral efficiency of wireless communication systems compared to the conventional RIS scheme.