International Workshop on RIS – Feb 22-23, 2024

FEB 22-23, 2024
19, Place Marguerite Perey, 92120, Palaiseau

Reconfigurable Intelligent Surfaces are very promising physical-layer candidates for sixth-generation cellular networks.

This international workshop will cover the main scientific and technological questions underlying this promise: electromagnetism, meta-materials, beamforming, adaptive control,network architecture, and network energy expenditure.

Day 1
  • Mathias FINK (ESPCI, France)
  • Markku JUNTTI (University of Oulu, Finland)
  • Mohsen KHALILY (University of Surrey, UK)
  • Alessio ZAPPONE (University of Cassino, Italy)
  • Angeliki ALEXIOU (University of Piraeus, Greece)
Day 2
  • Dinh-Thuy PHAN HUY (Orange, France)
  • Guodong SUN (Nokia Bell Labs, France)
  • Vincenzo SCIANCALEPORE (NEC Europe, Germany)
  • Luis UZEDA GARCIA (Nokia Standards, France)
  • Valeria LOSCRI (Inria, France)
  • Phlipp DEL HOUGNE (CNRS, France)

IMPORTANT! Registration is free but mandatory.




9h30: Enregistration and welcome breakfast

9h50 (10′): Opening remarks – François BACCELLI (LINCS, IMT-Télécom Paris, Inria) et Marco DI RENZO (Cnrs, CentraleSupélec)

10h00 (60′) : Keynote – Towards ultrawideband RIS: From Acoustics to Electromagnetism, by Dr. Mathias FINK (ESPCI, France)

RIS is proposed as a new paradigm for 6G. Today, RIS technology is essentially narrowband and uses tunable metasurfaces made of several hundred pixels with a local reflection coefficient arbitrary controlled with a varying phase. Such an approach is sufficient when dealing with a signal bandwidth of the order of the coherence bandwidth where the channel can be considered flat. However, when dealing with ultrawideband signals, a unique phase control for each pixel is not always enough and ones have to extend the RIS concept.

The same problem occurs also in the field of multi-user sound communications in reverberating environment with acoustic reconfigurable intelligent surfaces, Here, the reconfigurable surface needs to cover a wide range of frequencies spanning several decades. We will address this problem for 2 different scenarios.  One approach is designed for multiple carrier frequencies communication and used a RIS made of several hundred electronically-controlled adjustable Helmholtz resonators. The second approach is designed for transmitting broadband continuous spectra and it used feedback metasurfaces where each elementary cell works as a reconfigurable spatio-temporal filter mimicking a double time-reversal process.  The extension of these concepts in the microwave range will be discussed.

11h10 (50′) : 6G System Evolution and Joint Communications and Radar Sensing Design, by Dr. Markku JUNTTI (University of Oulu)

We discuss and summarize the architectural options for radar type sensing in cellular networks to enable integrated sensing and communications (ISAC) operations. The key characteristics of monostatic and multistatic radar operation are briefly reviewed and the design challenges for cellular ISAC are discussed. We focus then more closely to the design problem of downlink transmit beamforming at a base station serving multiple users and performing simultaneously monostatic target sensing. The waveform design principles are introduced for single and multiple targets. The implications of wideband multicarrier operation are described and the performance optimization in this regime is discussed. Both optimization-based algorithms and deep unfolding based data driven JCAS design are introduced. Finally, we briefly discuss the usage of reconfigurable intelligent surface (RIS) technology in this context. It is known to be useful for communications coverage and some examples on that front will be showcased.

14h00 (50′) : Practical Challenges in Reconfigurable Intelligent Surfaces: Cutting-edge Solutions and Future Prospects, by Dr. Mohsen Khalily ((University of Surrey, UK)

This talk explores practical aspects of Reconfigurable Intelligent Surfaces (RIS), with a specific focus on the challenges posed by the 5G and beyond landscape. The discussion begins by contrasting transmissive and reflective RIS, shedding light on their respective applications and capabilities. The introduction of the groundbreaking STAR RIS underscores its remarkable adaptability in both transmission and reflection scenarios.

A notable challenge in RIS technology centers around user localization, adding a layer of complexity to its implementation. This talk introduces a potential solution by seamlessly integrating sensing and communication into the RIS platform, facilitating simultaneous target detection and communication link establishment. Through the strategic use of a shared spectrum, this approach optimizes channel performance, minimizing mutual interference.

Join us for an insightful journey into the evolving realm of RIS, featuring cutting-edge prototypes and inventive solutions poised to reshape the landscape of wireless communication and localization in the 5G and beyond era.

15h00 (50′) : Reconfigurable intelligent surfaces for energy-efficient 6G wireless networks, by Dr. Alessio ZAPPONE (University of Cassino, Italy)

Reconfigurable Intelligent Surfaces have emerged as a prominent technology for sixth-generation wireless networks. In particular, their ability to provide high energy efficiency without sacrificing rate performance is a very attractive feature, considering the need for extreme energy efficiency increase win future wireless communications. This talk will address the main approaches for an energy-efficient network design of RIS-aided wireless networks, discussing the latest research advances in the field as well as recent project and standardization activities.

16h00 (50′) : RIS for 6G – A fast track to Perceptive Networks, by Dr. Angeliki ALEXIOU (University of Piraeus, Greece)

Wireless networks are nowadays shifting to higher operation frequencies with the aim to meet the ever-increasing demand for bandwidth as well as new revolutionary beyond communications requirements, associated with resilience, environmental and situational awareness, and immersive, sensing-aided and sensing-capable intelligence. Reconfigurable intelligent surfaces (RISs) are typically utilized in the far-field as an effective means of creating line-of-sight (LOS) links to mediate non-LOS propagation. Owing to their large aperture, the use of RISs can be extended in the near-field and can be exploited to perform advanced wavefront engineering, essentially transforming the incident beam into a non-trivial reflected beam tailored to address the challenges of future -beyond just- communication systems.

In this talk an analytical framework is presented to explain, in qualitative and quantitative terms, how RISs can engineer wavefronts to transform the incident beam and what are the dependencies and trade-offs between crucial parameters, such as the incident beam footprint on the RIS, the intended focal distance of the reflected beam, the link topology etc. The RIS potential as enabler for perceptive, resilient, and efficient future networks is discussed, and a RIS-based localization algorithm, employing a hybrid beamforming/beamfocusing scheme, is used as an illustrative example.


8h30 Welcome breakfast

9h00 (50′) : Reconfigurable Intelligent Surfaces for 6G: a network operator point of view, by Dr. Dinh-Thuy PHAN HUY ( Orange, France)

To support the continuous growth of the Internet traffic over the last two decades, each new generation of mobile network (3G, 4G, 5G) has been improved with respect to the previous generation, in terms of spectral efficiency, capacity, and energy efficiency. However, from a network operator perspective, each new generation also adds its own cost, in terms of resources such as spectrum, infrastructure deployment  and energy consumption, to the costs of all previous deployed generations. Moreover, it adds its own contribution in terms of carbon footprint to the environment and it adds-up to the overall exposure of the Society to Electro-Magnetic Field. Finally, new deployments which do not meet customers or business customers needs, have limited business value. 6G, currently still at the Research stage, has the opportunity to be the first generation to explore disruptive approaches to meet Environment sustainability, Societal sustainability and Economical sustainability. As an example of such disruption, Reconfigurable Intelligent Surface is a new wireless network node which reuses existing waves, is expected to consume less power and can even be made from refurbished material. In this talk, based on our studies and field trials of prototypes with our partners, we analyse the potential of this technology. We elaborate on how it could to meet some business and society needs, whilst reusing existing resources and limiting its impact on the environment. We will also analyse the limitations and challenges ahead, especially in terms of availability of prototypes, trials, spectrum coexistence and integration into standards of wireless networks.

10h00 (50′) : Performance Analysis of RIS-assisted MIMO-OFDM Cellular Networks Based on Matern Cluster Processes, by PhD Guodong SUN (Nokia Bell Labs, France)

Reconfigurable Intelligent Surfaces (RIS) technology is a promising physical-layer candidate for sixth-generation (6G) cellular networks. Our work provides a system-level performance assessment of RIS-assisted multi-input multi-output (MIMO) cellular networks in terms of downlink coverage probability and ergodic rate. To capture the inherent randomness in the spatial deployments of both Base Stations (BSs) and RISs, we propose a new stochastic geometry model for such systems based on the Matern Cluster Process (MCP).  This model consists in randomly distributed RISs around BSs, whose placement is according to a Poisson Point Process (PPP). The RISs provide the multipath diversity and the multiple antennas at receivers provide the antenna diversity. The system is assumed to use the orthogonal frequency division multiplexing (OFDM) technique to modulate the former and employ the maximal ratio combining (MRC) technique at the receiver to exploit the latter. We show that the coverage probability and the ergodic rate can be evaluated when considering RISs operate as batched powerless beamformers. The resulting analytical expressions provide a generic methodology to evaluate the impact of key RIS related parameters, such as the size of RISs and the density of nodes, on system level performance. In practice, operators can decide between deploying additional RISs or increasing the density of BSs. We show how the proposed model allows one to conduct a techno-economic analysis of future RIS-assisted cellular networks.

11h00 (50′) : Eco-Friendly 6G: Integrating Sustainability with RIS and ISAC Innovations, by Vincenzo SCIANCALEPORE (NEC Europe, Germany)

In the era of rapid technological advancement, the forthcoming 6G networks promise unprecedented levels of connectivity, speed, and efficiency. However, the environmental impact of these technologies cannot be overlooked. The exploitation of Reconfigurable Intelligent Surfaces (RIS) as key-enabler for the recently-established concept of Integrated Sensing and Communication (ISAC) presents a unique opportunity to redefine the landscape of wireless communication with an emphasis on sustainability. This talk explores how RIS and ISAC, as pioneering technologies, are set to revolutionize 6G networks by not only enhancing performance and efficiency but also significantly reducing the energy consumption and carbon footprint associated with next-generation wireless systems.

12h00 (20′) : RIS from the 3GPP perspective, by Dr. Luis UZEDA GARCIA (Nokia Standards, France)

This presentation explores the integration of Reconfigurable Intelligent Surfaces (RIS) within the framework of 5G-Advanced and anticipates the evolving landscape of 6G networks. Focusing on the standardization efforts led by the 3rd Generation Partnership Project (3GPP). Attendees will gain insights into the latest advancements, challenges, and opportunities associated with standardizing RIS technologies. The presentation aims to provide a comprehensive overview of the standardization process, highlighting key considerations for the seamless incorporation of RIS into the next generation of wireless communication standards.

14h00 (50′) : Reconfigurable Intelligent Surfaces: a key-enabler technology for Beyond-5G networks, by Dr. Valéria LOSCRI (Inria, France)

Beam-steering capabilites of Reconfigurable Intelligent Surfaces (RIS) are a desired feature in the context of wireless networks to enabling advanced coverage applications.
Higher frequencies, in the band of mmWave, can be considered to meet the always increasing demanding of resources in advanced wireless systems.
In this talk, a RIS working in mmWave bandwidth is considered in a mobile urban context for user’s coverage purpose. The proposed RIS is with angle insensitive features, meaning that independently of the incidence angle, the beam-steering capabilities can be ensured with a sufficient accuracy. In the mobile city context, another crucial point is the derivation of the input to feed the RIS and compute the new direction of the beam with a delay that can be “tolerated” by the mobility of a user. For this purpose, we have investigated the co-existence of the RIS infrastructure with a Computer Vision infrastructure and considered a platform, where the two frameworks are integrated and used to enabling a user track coverage application.

15h00 (50′) : Physics Compliant Modeling & Estimation of RIS Parametrized Wireless Channels, by Dr. Philipp DEL HOUGNE (CNRS, France)

In this talk, Dr. Del Hougne will discuss two equivalent approaches to physics-compliant modelling of RIS-parametrized wireless channels in non-trivial radio environments (i.e., involving scattering objects): a polarizability-based approach and a load-impedance-based approach. He will discuss how the parameters of these approaches can be estimated in any given but unknown experimental setting, revealing that physics-compliant channel estimation can be extremely frugal in terms of the number of required measurements, but also because it does not require phase measurements. Finally, he will present the first experimental demonstration of physical-model-based wave control in complex RIS-parametrized radio environments.

[1]          R. Faqiri, C. Saigre-Tardif, G. C. Alexandropoulos, N. Shlezinger, M. F. Imani, and P. del Hougne, “PhysFad: Physics-Based End-to-End Channel Modeling of RIS-Parametrized Environments With Adjustable Fading,” IEEE Trans. Wirel. Commun., vol. 22, no. 1, pp. 580–595, Jan. 2023.

[2]          H. Prod’homme and P. del Hougne, “Efficient Computation of Physics-Compliant Channel Realizations for (Rich-Scattering) RIS-Parametrized Radio Environments,” IEEE Commun. Lett., vol. 27, no. 12, pp. 3375–3379, Dec. 2023.

[3]          J. Sol, H. Prod’homme, L. L. Magoarou, and P. del Hougne, “Experimentally realized physical-model-based wave control in metasurface-programmable complex media,” arXiv:2308.02349, Jul. 2023.

[4]          J. Tapie, H. Prod’homme, M. F. Imani, and P. del Hougne, “Systematic Physics-Compliant Analysis of Over-the-Air Channel Equalization in RIS-Parametrized Wireless Networks-on-Chip.” arXiv, Oct. 2023.

16h00 (50′) : Towards Semantic, Goal-Oriented and Reconfigurable Intelligent Environments aided 6G communications, by Dr. Emilio CALVANESE STRINATI (CEA, France)

This talk promotes the idea of combining semantic and goal-oriented aspects with the reconfigurable and intelligent wireless environments paradigm. The idea is that, whenever communication occurs to convey meaning or to accomplish a goal, what really matters is the impact that the correct reception/interpretation of a packet is going to have on the goal accomplishment. This influence also how adaptive settings for reconfigurable intelligent surfaces should be selected. After a short presentation of most recent state of the art approaches, we present our most recent results and cover in detail challenges and opportunities associated with the evolution towards semantic, goal-oriented and reconfigurable intelligent environments aided 6G communications.

Download the program =>   WS RIS FEB 22&23 2024

Please note that :
  • The adresse of the venue of the workshop is 19, Place Marguerite Perey, 91123 Palaiseau; Please announce yourself at the welcome desk and ask direction to Amphithéatrhe Rose Dieng-Kunts (direction signs will help you)
  • Join the conférence by public transportations : RER B (direction Sud) towards St. Rémi-les-Chevreuse, or Orsay Ville, or Massy-Palaiseau => then please alight at Massy-Palaiseau and look for BUS 91.06 towards Christ de Saclay, and get off at Ferme de la Vauve.