Reconfigurable Intelligent Surfaces: Localization and Communication Convergence

Tuesday, 8 June 2021, 09:30-13:00, Zoom Room
  • George C. Alexandropoulos (National & Kapodistrian University of Athens, Greece)
  • Henk Wymeersch (Chalmers Universityof Technology, Sweden)

Motivation and Context

In order to realize the gains of RISs, localization and communication must be tightly coupled and co-designed. This is in sharp contrast to 5G and earlier wireless network generations, where localization was an additional, secondary service. The under lying reason is that an RIS fundamentally provides a localized service, impacting its local environment. This implies that communication and localization professionals need to understand the properties of RISs from both perspectives, in order to realize powerful co-designs where communication and localization reinforce each other. The goal of this tutorial is to provide attendees with an overview of the state-of-the-art in communication and localization, as well as their interaction. To do so, the latest advances in the RIS modeling and signal processing for RIS-empowered networks will be presented in conjunction with the RIS killer applications as envisioned by the recent EU projects RISE-6G and Hexa-X. One of the main selling points of this tutorial, which sets it apart from other tutorials on RIS, is this dual perspective, taught by renowned researchers in these two fields.


Structure and Content

Part I – Fundamentals (1 hour)


  • Smart radio environments
  • RIS hardware architectures
  • Emerging applications and challenges

RIS Fundamentals and Modeling

  • Unit cell modeling
  • Received signal model
  • Competing technologies (relay)

RIS killer applications

  • Communication
  • Localization and sensing

Part II – Communication (1 hour)

Channel Estimation

  • Cascade channel estimation
  • RISs with active sensing elements

RIS-enabled Communication

  • Placement optimization
  • Phase design optimization formulations (e.g.,for security, including problem formulations)
  • Capacity results
  • I/ML orchestration

Part III – Localization (1 hour)

Radio localization

  • 4G, 5G, B5G and the Hexa-X and RISE-6G visions

Channel Estimation

  • Parametric channel estimation
  • RISs with active sensing elements

RIS-enabled Localization and Mapping

  • Architectures: Passive, active RISs, Lens RISs
  • Placement and phase optimization (profile design)
  • Performance bounds
  • Algorithms

George C. Alexandropoulos

George C. Alexandropoulos, received the Engineering Diploma, M.A.Sc., and Ph.D. degrees in computer engineering and informatics from the University of Patras, Greece in 2003, 2005, and 2010, respectively. He has held research positions at various Greek universities and research institutes, as well as at the Mathematical and Algorithmic Sciences Lab, Paris Research Center, Huawei Technologies France, and he is currently an Assistant Professor with the Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, 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, active and passive reconfigurable metasurfaces, millimeter wave communications, as well as distributed machine learning algorithms. He has received the best Ph.D. thesis award 2010 and the IEEE Communications Society Best Young Professional in Industry Award 2018.More information is available at

Henk Wymeersch

Henk Wymeersch, obtained the Ph.D. degree in Electrical Engineering/Applied Sciences in 2005 from Ghent University, Belgium. He is currently a Professor of Communication Systems with the Department of Electrical Engineering at Chalmers Universityof Technology, Sweden. He is also a Distinguished Research Associate with Eindhoven Universityof Technology. Prior to joining Chalmers, he was a post-doctoral researcher from 2005 until 2009 with the Laboratory for Information and Decision Systems at the Massachusetts Institute of Technology. Prof. Wymeersch served as Associate Editor for IEEE Communication Letters(2009-2013), IEEE Transactions on Wireless Communications (since 2013), and IEEE Transactions on Communications (2016-2018). During 2019-2021, he was an IEEE Distinguished Lecturer with the Vehicular Technology Society. His current research interests include the convergence of communication and sensing, in 5G and Beyond 5G context. More information is available at