16 citations · 16 across the 41 of their papers we have counts for
32 papers · 1 filter
Structured PARAFAC Channel Estimation for Flexible Intelligent Metasurface Receivers
Xi Han, Junqiao Chen, Yuansheng Zhang +2
Flexible intelligent metasurfaces (FIMs) create geometric diversity through aperture morphing, but their configuration-dependent responses complicate uplink channel estimation. Thi…
Simultaneous Secure Communications and Sensing Privacy with Full Duplex MIMO Radios
Ioannis Gavras, George C. Alexandropoulos
This paper proposes a Full Duplex (FD) framework for safeguarding Integrated Sensing and Communications (ISAC) against a passive multi-antenna Eavesdropper (Eve). The adversary is…
Over-The-Air Extreme Learning Machines with Nonlinear Stacked Intelligent Metasurfaces
Kyriakos Stylianopoulos, Mattia Fabiani, Giulia Torcolacci +2
The recently envisioned goal-oriented communications paradigm requires machine learning inference to be performed directly on wirelessly transferred data. This paper presents an eX…
Energy Efficient Multi-User Beamforming and 3D Position Optimization for SIM-Assisted UAVs
Chandan Kumar Sheemar, Giovanni Iacovelli, Sourabh Solanki +3
This paper studies energy-efficient downlink multi-user transmissions with unmanned aerial vehicle (UAV) communication systems equipped with stacked intelligent metasurfaces (SIM),…
TenSIM: Tensor-Based Channel Estimation for MIMO Systems with Stacked Intelligent Metasurfaces
André L. F. de Almeida, George C. Alexandropoulos
Stacked intelligent metasurfaces (SIMs) are emerging as a promising architecture for sixth-generation (6G) and beyond wireless systems, enabling richer electromagnetic-wave manipul…
RIS Beamforming under Element-Level Variations: Statistical Characterization and Robust Design
Dimitris Kompostiotis, Dimitris Vordonis, Vassilis Paliouras +1
In this paper, a novel analytical framework to characterize the impact of element-level variations on the radiation characteristics of reconfigurable intelligent surfaces (RISs) is…
Robust Beamforming for Cell-Free Systems with Parallel-Plate-Waveguided Dynamic Metasurfaces
Konstantinos D. Katsanos, Panagiotis Gavriilidis, George C. Alexandropoulos
Dynamic Metasurface Antennas (DMAs) constitute a promising solution for extremely large antenna arrays, requiring lower power consumption and reduced hardware cost as compared to c…
A Near-Field Compatible Model for 2D Waveguide-Fed Metasurfaces
Panagiotis Gavriilidis, George C. Alexandropoulos
This paper presents a novel physically consistent analytical model for two-dimensional (2D) waveguide-fed metasurface antennas that is based on the discrete dipole approximation. T…
Near-Field Beam Focusing Characterization for 2D Waveguide-Fed Metasurface Antennas
Panagiotis Gavriilidis, George C. Alexandropoulos
Two-dimensional (2D) waveguide-fed metasurfaces enable scalable antenna apertures through guided wave excitation of distributed radiating elements. However, the resulting non-unifo…
2D Waveguide-Fed Metasurfaces: Physically Consistent Modeling, Validation, and Optimization
Panagiotis Gavriilidis, George C. Alexandropoulos
Antenna array architectures based on programmable metasurfaces are emerging as a promising solution for scalable implementations of the eXtremely Large Multiple-Input Multiple-Outp…
Low-Complexity Learning-Based Beamforming for Ultra-Massive MIMO THz Communications
Sourabh Solanki, Abuzar Babikir Mohammad Adam, Chandan Kumar Sheemar +4
Terahertz (THz) communications have emerged as a key technology for escalating data rates in future generation wireless networks. However, severe propagation losses at THz frequenc…
Wideband Sensing with Dynamic Metasurface Antennas under Realistic Phase Response Modeling
Ioannis Gavras, George C. Alexandropoulos
This paper investigates the impact of practical features of the emerging antenna array technology of Dynamic Metasurface Antennas (DMAs) when used for wideband sensing. By adopting…
Multi-User Symbol Detection with XL Reception: Dynamic Metasurface Antennas with Low Resolution ADCs
Rahul K. Pal, Soumya P. Dash, Barathram Ramkumar +1
Dynamic Metasurface Antennas (DMAs) have been recently proposed as a cost- and energy-efficient front-end solution for eXtremely Large (XL) antenna array systems, supporting scalab…
Symbol Error Analysis for Fluid Antenna Systems with One- and Two-Dimensional Modulation Schemes
Soumya P. Dash, George C. Alexandropoulos
This paper considers a Fluid Antenna (FA) system comprising a single-antenna transmitter that communicates with a receiver equipped with an FA array with ports. The transmitter…
Toward Integrated Sensing, Communications, and Edge Intelligence Networks
Mattia Merluzzi, Miltiadis C. Filippou, Paolo Di Lorenzo +1
Wireless systems are expanding their purposes, from merely connecting humans and things to connecting intelligence and opportunistically sensing of the environment through radio-fr…
A Survey on Stacked Intelligent Metasurfaces: Fundamentals, Recent Advances, and Challenges
Chandan Kumar Sheemar, Wali Ullah Khan, Sourabh Solanki +2
Reconfigurable intelligent surfaces (RISs) enable programmable control of wireless propagation. Beyond environmental deployments, integrating metasurfaces at the antenna front end…
RIS-Enabled Spoofing Against Adversary Sensing: CRB-Maximizing Design and Decoying Analysis
Ioannis Gavras, Giuseppe Thadeu Freitas de Abreu, George C. Alexandropoulos
This paper studies the capability of a Reconfigurable Intelligent Surface (RIS), when transparently covering a User Equipment (UE), to deceive an adversary monostatic radar system.…
Over-The-Air Extreme Learning Machines with XL Reception via Nonlinear Cascaded Metasurfaces
Kyriakos Stylianopoulos, Mattia Fabiani, Giulia Torcolacci +2
The recently envisioned goal-oriented communications paradigm calls for the application of inference on wirelessly transferred data via Machine Learning (ML) tools. An emerging res…
RIS-Enabled Smart Wireless Environments: Fundamentals and Distributed Optimization
George C. Alexandropoulos, Kostantinos D. Katsanos, George Stamatelis +1
This chapter overviews the concept of Smart Wireless Environments (SWEs) motivated by the emerging technology of Reconfigurable Intelligent Surfaces (RISs). The operating principle…
2D Waveguide-Fed Metasurface Antenna Arrays: Modeling and Optimization for Bistatic Sensing
Ioannis Gavras, Panagiotis Gavriilidis, George C. Alexandropoulos
This paper presents a physics-consistent framework for bistatic sensing incorporating a 2-Dimensional (2D) waveguide-fed metasurface antenna array capable of realizing eXtremely-La…
Electromagnetics-Compliant Optimization of Dynamic Metasurface Antennas for Bistatic Sensing
Ioannis Gavras, George C. Alexandropoulos
Dynamic Metasurface Antennas (DMAs) are recently attracting considerable research interests due to their potential to enable low-cost, reconfigurable, and highly scalable antenna a…
Metasurfaces-Integrated Doubly-Dispersive MIMO: Channel Modeling and Optimization
Kuranage Roche Rayan Ranasinghe, Hyeon Seok Rou, Iván Alexander Morales Sandoval +2
The doubly-dispersive (DD) channel structure has played a pivotal role in wireless communications, particularly in high-mobility scenarios and integrated sensing and communications…
Parametrized Stacked Intelligent Metasurfaces for Bistatic Integrated Sensing and Communications
Kuranage Roche Rayan Ranasinghe, Iván Alexander Morales Sandoval, Giuseppe Thadeu Freitas de Abreu +1
We consider stacked intelligent metasurfaces (SIMs) as a tool to improve the performance of bistatic integrated sensing and communications (ISAC) schemes. To that end, we optimize…
Communications-Centric Secure ISAC with Hybrid Reconfigurable Intelligent Surfaces
Ioannis Gavras, George C. Alexandropoulos
Hybrid reconfigurable intelligent surfaces (HRISs) constitute an emerging paradigm of metasurfaces that empowers the concept of smart wireless environments, inherently supporting s…