Channel Estimation and Hybrid Architectures for RIS-Assisted Communications
This work addresses foundational challenges for deploying RIS technology to enhance wireless communication systems, but it is incremental as it reviews existing research rather than presenting new breakthroughs.
The paper tackles the need to address fundamental issues in reconfigurable intelligent surfaces (RISs) for 6G wireless communications, such as physical-layer modelling, channel estimation, and phase control, by providing an overview of these problems and recent numerical results.
Reconfigurable intelligent surfaces (RISs) are considered as potential technologies for the upcoming sixth-generation (6G) wireless communication system. Various benefits brought by deploying one or multiple RISs include increased spectrum and energy efficiency, enhanced connectivity, extended communication coverage, reduced complexity at transceivers, and even improved localization accuracy. However, to unleash their full potential, fundamentals related to RISs, ranging from physical-layer (PHY) modelling to RIS phase control, need to be addressed thoroughly. In this paper, we provide an overview of some timely research problems related to the RIS technology, i.e., PHY modelling (including also physics), channel estimation, potential RIS architectures, and RIS phase control (via both model-based and data-driven approaches), along with recent numerical results. We envision that more efforts will be devoted towards intelligent wireless environments, enabled by RISs.