Hybrid reconfigurable intelligent surfaces: From channel estimation improvement to self-optimization

Presenter: George C. Alexandropoulos, National and Kapodistrian University of Athens

Abstract: The advent of the connected things paradigm in 5G enabled various sophisticated applications, whose evolution paves the way for the notion of the connected intelligence of everything in the future 6G networks. Recent speculations for this upcoming new generation push the 5G performance indicators to unprecedented levels, envisioning THz frequency bands, devices with embedded sensing capabilities, and native artificial intelligence. In this talk, we will discuss the emerging technology of simultaneously reflecting and sensing Reconfigurable Intelligent Surfaces (RISs), which is provisioned as an efficient enabler of smart wireless environments, offering a highly scalable, low-cost, and hardware-efficient solution for wave propagation control. We will present an efficient hardware design for such hybrid metasurfaces and elaborate on their utilization for explicit and parametric channel estimation as well as for localization. Their potential for self-optimization, which will severely reduce control signaling, will be highlighted together with relevant open research challenges and promising applications.

Speaker bio:George C. Alexandropoulos received the Diploma degree in computer engineering and informatics (integrated M.Sc.), the M.A.Sc. degree in signal and communications processing systems, and the PhD degree in wireless communications from the School of Engineering, University of Patras, Greece in 2003, 2005, and 2010, respectively. He has held senior research positions at various Greek universities and research institutes, and he was a senior research engineer and a principal researcher at the Mathematical and Algorithmic Sciences Lab, Paris Research Center, Huawei Technologies France, and at the Technology Innovation Institute, Abu Dhabi, United Arab Emirates, respectively. He is currently an assistant professor with the Department of Informatics and Telecommunications, School of Sciences, National and Kapodistrian University of Athens (NKUA), Greece. His research interests span the general areas of algorithmic design and performance analysis for wireless networks with emphasis on multi-antenna transceiver hardware architectures, full duplex radios, active and passive Reconfigurable Intelligent Surfaces (RISs), integrated communications and sensing, millimeter wave and THz communications, as well as distributed machine learning algorithms. Alexandropoulos currently serves as an editor for IEEE Transactions on Communications, IEEE Wireless Communications Letters, Frontiers in Communications and Networks, and the ITU Journal on Future and Evolving Technologies. In the past, he has held various fixed-term and guest editorial positions for IEEE Transactions on Wireless Communications, IEEE Communications Letters, and ELSEVIER Computer Networks, as well as for various special issues at IEEE journals.  Alexandropoulos is a senior member of the IEEE Communications, Signal Processing, Vehicular Technology, and Information Theory Societies, the vice-chair of the EURASIP Technical Area Committee on Signal Processing for Communications and Networking, as well as a registered professional engineer of the Technical Chamber of Greece. He is also a distinguished lecturer of the IEEE Communications Society. He has participated and/or technically managed more than 15 European Union (EU), international, and Greek research, innovation, and development projects. He is currently NKUA's principal investigator for the EU H2020 RISE‑6G and the SNS JU TERRAMETA projects dealing with RIS- empowered smart wireless environments and THz RISs, respectively. For the former project he serves as the dissemination manager, whereas for the latter, he serves as the technical manager. Alexandropoulos has received the best PhD thesis award 2010, the IEEE Communications Society Best Young Professional in Industry Award 2018, the EURASIP Best Paper Award of the Journal on Wireless Communications and Networking 2021, the IEEE Marconi Prize Paper Award in Wireless Communications 2021, and a Best Paper Award from the IEEE GLOBECOM 2021. More information is available at www.alexandropoulos.info.

Faculty host: Besma Smida, smida@uic.edu

This meeting will be held online via Zoom. Please contact the department for login credentials.