S. Chatzinotas

Protocol-Aware Jamming and Self-Play Defense for Active RIS-Assisted UAV Communications

Active reconfigurable intelligent surfaces (RISs) mounted on unmanned aerial vehicles (UAVs) can restore blocked wireless links by combining aerial repositioning, controllable reflection, and element-level amplification. However, this amplification creates a dual-use vulnerability: a jammer whose signal reaches the act...

Hybrid Optimization-Learning for Interference Management in Coexisting NTN–TN Systems

Spectrum sharing between non-terrestrial networks (NTNs) and terrestrial networks (TNs) represents a key enabler for enhancing spectrum utilization in next-generation wireless systems. However, such coexistence introduces severe crossnetwork interference. Power control is an effective mechanism to mitigate this interfe...

Distributed Constrained Resource Management in 6G Networks: A Scalable Hybrid Model-Learning Framework

Radio Resource Management (RRM) is a fundamental challenge in 6G wireless networks, particularly under dynamic user demands, inter-cell interference, and heterogeneous QoS constraints. Centralized optimization solutions are often infeasible in practice due to the lack of system-wide state information, dynamic condition...

Handover-Aware Resource Allocation for Aerial RU-Assisted Open RAN Systems

Open radio access network (Open RAN) disaggregation across the distributed unit (DU), centralized unit (CU), and near-real-time radio intelligent controller (near-RT RIC) enables programmable, hierarchical radio access control. This architectural split allows independent optimization of short-term resource management a...

Hybrid Learning Design for Distributed Constrained Resource Optimization in 6G Networks

Distributed Radio Resource Management (RRM) is a fundamental challenge in 6G wireless networks, particularly under dynamic user demands, multilayer inter-cell interference, and heterogeneous QoS constraints. Centralized optimization solutions are often infeasible in practice due to signaling delay and the lack of syste...

Predictive Routing for NB-IoT Uplink Traffic over a Very Low Earth Orbit (VLEO) Satellite Constellation

Very low Earth orbit (VLEO) satellite constellations are a promising platform for uplink-dominated narrowband internet of things (NB-IoT) services. However, rapid topology variations and short satellite-gateway and satellite-user contact durations introduce significant routing challenges. This paper proposes a predicti...

6DMA-FIM-Enabled User-Centric Cell-Free Massive MIMO With Two-Layer RSMA

This paper proposes a novel user-centric (UC) cell-free massive MIMO (CF-mMIMO) architecture empowered by six-dimensional movable antennas (6DMA) and flexible intelligent metasurfaces (FIM), integrated with a two-layer rate-splitting multiple access (RSMA) framework. Unlike conventional fixed-position deployments, the...

Exploiting Movable-Element STARS for Rate Splitting Multiple Access

This paper investigates a movable-element simultaneously transmitting and reflecting reconfigurable intelligent surface (ME-STARS) assisted rate-splitting multiple access (RSMA) system under imperfect channel state information (CSI). Unlike conventional STARS with fixed element positions, the elements of ME-STARS can b...

Leveraging Movable-Element STARS for RSMA-SWIPT Under Practical System Imperfections

We study a robust multiuser framework for simultaneous wireless information and power transfer (SWIPT), where rate-splitting multiple access (RSMA) is integrated with a movable-element simultaneously transmitting and reflecting surface (ME-STARS). By allowing the STARS elements to change their positions in addition to...

Cost-Effective Antenna Terminals for Direct-to-Vehicle Satellite Communications

Stacked Fluid Metasurfaces: Mutual-Coupling-Aware Modeling and Optimization

Stacked intelligent metasurfaces process the transmitted field layer by layer, and fluid antennas make the position of every radiator a design variable. Combined, they pack radiators at sub-wavelength spacings within and across layers, where mutual coupling governs the physics that current models omit. This paper devel...

Polarforming-Enabled Power-Splitting SWIPT: A GNN-Based Optimization Approach

Simultaneous wireless information and power transfer (SWIPT) is a critical technology for the future of the Internet of Things (IoT). However, ensuring a stable power supply in such networks remains a significant challenge. This work introduces dynamic polarization control as an additional degree of freedom (DoF) in SW...