Hongliang Zhang - Reconfigurable Intelligent Surface-Empowered 6G (Wireless Networks)

The purpose of Springer's Wireless Networks book series is to establish the state of the art and set the course for future research and development in wireless communication networks. The scope of this series includes not only all aspects of wireless networks (including cellular networks, WiFi, sensor networks, and vehicular networks), but related areas such as cloud computing and big data. The series serves as a central source of references for wireless networks research and development. It aims to publish thorough and cohesive overviews on specific topics in wireless networks, as well as works that are larger in scope than survey articles and that contain more detailed background information. The series also provides coverage of advanced and timely topics worthy of monographs, contributed volumes, textbooks and handbooks.

** Indexing: Wireless Networks is indexed in EBSCO databases and DPLB **

More information about this series at http://www.springer.com/series/14180

This Springer imprint is published by the registered company Springer Nature Switzerland AG

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Launching from fifth-generation communications, which provide a single platform enabling a variety of data services, evolution towards sixth-generation (6G) has been kicked off, envisioning future wireless networks to become distributed intelligent communications, sensing, and localization systems. Though such a demand has gained support from existing techniques such as massive MIMO and small cells, they heavily depend on the quality of the uncontrollable wireless environments. Differently, reconfigurable intelligent surface (RIS) as a new type of ultra-thin meta material inlaid with multiple sub-wavelength scatters can create favorable propagation conditions by controlling the phase shifts of the reflected waves at the surface such that the received signals are directly reflected towards the receivers without any extra cost of power sources or hardware. It provides a revolutionarily new approach to actively improve the link quality and coverage, which sheds light into the future 6G. Due to the coupling between radio propagation and discrete phase shifts of RIS, existing protocols and design methodologies cannot be directly applied any more. Therefore, it is essential to develop new communication and signal processing techniques and to explore various RIS-based applications such as intelligent sensing and localization.

In this book, novel RIS-based smart radio techniques are discussed, targeting at achieving high-quality channel links in cellular communications via design and optimization of RIS construction. Unlike traditional antenna arrays, three unique characteristics of RIS will be revealed. First, the built-in programmable configuration of RIS enables analog beamforming inherently without extra hardware or signal processing. Second, the incident signals can be controlled to partly reflect and partly transmit through the RIS simultaneously, adding more flexibility to signal transmission. Third, RIS has no digital processing capability to actively send signals nor any radio frequency (RF) components. As such, it is necessary to develop novel channel estimation and communication protocols, design joint digital and RIS-based analog beamforming schemes, and perform interference control via mixed reflection and transmission.

The aim of this book is to educate control and signal processing engineers, computer and information scientists, applied mathematicians and statisticians, as well as systems engineers to carve out the role that analytical and experimental engineering has to play in RIS research and development. This book will emphasize on RIS technologies and applications for future communications.