Intelligent Omni-Surfaces: Ubiquitous Wireless Transmission by Reflective-Refractive Metasurfaces

The development of metasurfaces has provided a novel multi-antenna technology for wireless communication networks to improve performance by manipulating the propagation environment. Intelligent omni-directional surface (IOS) is proposed for coverage extension via its high spatial diversity gain. Capable of integrating a massive number of elements without introducing extra hardware cost compared to the traditional phased arrays, the IOS technique serves as a cost-efficient method to achieve massive MIMO. In contrast to the widely studied reflective metasurfaces, i.e., intelligent reflecting surfaces (IRSs), which can only serve receivers located on the same side of the transmitter, the IOS enables wireless transmission by enabling the simultaneous reflection and refraction of the surface, similar to a two-sided mirror, and thus, users on both sides can be served. In this tutorial, a comprehensive overview of the state-of-the-art IOS-related research is provided from the perspective of wireless communications, with the emphasis on their design principles, beamforming design, experimental implementation and measurements. I will first describe the basic concepts of IOS, and introduce its great potential in realizing massive MIMO. The key techniques for the IOS enabled wireless communications are then provided. Following that, I will present the implementation of our own developed IOS-aided wireless communication prototype and report its experimental measurement results. Finally, some of our ongoing works on intelligent surfaces will also be briefly introduced.

Boya Di (S’17-M’19) has been working as an assistant professor at Peking University since 2021. She obtained her B.S. degree and Ph.D. degree from Peking University, China, in 2014 and 2019. She was a postdoc researcher at Imperial College London after graduation. Her current research interests include holographic surfaces, reconfigurable intelligent surfaces, edge computing, and aerial access networks. Since 2020, she has given tutorial talks at IEEE GlobeCom/ICC conferences for more than 5 times. She is the recipient of 2021 IEEE ComSoc Asia-Pacific Outstanding Paper Award and 2022 IEEE ComSoc Asia-Pacific Outstanding Young Researchers Award. She serves as an associate editor for IEEE Transactions on Vehicular Technology, IEEE Internet of Things Journal, IEEE Communications & Surveys, and IEEE Transactions on Machine Learning in Communications and Networking. She has also served as a workshop co-chair for IEEE WCNC 2020&2021 and ISWCS 2022.