376 citations · 528 across the 84 of their papers we have counts for
92 papers
Terahertz Inter-Satellite Links: Motivation, Challenges and Opportunities
Chandan Kumar Sheemar, Wali Ullah Khan, Giovanni Iacovelli +5
Inter-satellite links (ISLs) are essential to the evolution of next-generation satellite constellations, providing the foundation for low-latency, resilient, and globally scalable…
Transmissive RIS-Assisted Vehicular Direct-to-Satellite Communications: Opportunities, Limitations, and Comparison with Phased Arrays
Wali Ullah Khan, Abdullah Abdullah, Juan Andres Vazquez-Peralvo +1
This article studies transmissive reconfigurable intelligent surface (RIS)-assisted architectures. It compares them with electronically steered phased arrays for the deployment of…
Extremely Large Beyond-Diagonal RIS: Low-Rank Modal Optimization for Near-Field Communications
Giovanni Iacovelli, Chandan Kumar Sheemar, Eva Lagunas +1
Beyond-diagonal reconfigurable intelligent surfaces (BD-RIS) achieve their best performance when fully connected, at the price of an optimization and hardware burden that grows qua…
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…
A Joint JSCC-Resource Allocation Framework for QoS-Aware Semantic Communication in LEO Satellite-based EO Missions
Hung Nguyen-Kha, Ti Ti Nguyen, Vu Nguyen Ha +3
In Earth observation (EO) missions with Low Earth orbit (LEO) satellites, high-resolution image acquisition generates a massive data volume that poses a significant challenge for t…
Handover-Aware Power Minimization for Networked LEO Satellite Communications: Joint Cooperative Beamforming and Scheduling
Yuchen Zhang, Eva Lagunas, Symeon Chatzinotas +1
Networked low Earth orbit (LEO) satellite constellations enabled by inter-satellite links offer a promising path toward ubiquitous broadband non-terrestrial services, as cooperativ…
Digital-Twin-Aided Dynamic Spectrum Sharing and Resource Management in Integrated Satellite-Terrestrial Networks
Hung Nguyen-Kha, Vu Nguyen Ha, Ti Nguyen +4
The explosive growth in wireless service demand has prompted the evolution of integrated satellite-terrestrial networks (ISTNs) to overcome the limitations of traditional terrestri…
Resilience Optimization in 6G and Beyond Integrated Satellite-Terrestrial Networks: A Deep Reinforcement Learning Approach
Dinh-Hieu Tran, Nguyen Van Huynh, Van Nhan Vo +3
Ensuring network resilience in 6G and beyond is essential to maintain service continuity during base station (BS) outages due to failures, disasters, attacks, or energy-saving oper…
Decentralized Cooperative Beamforming for Networked LEO Satellites with Statistical CSI
Yuchen Zhang, Eva Lagunas, Xue Xian Zheng +2
Inter-satellite-link-enabled low-Earth-orbit (LEO) satellite constellations are evolving toward networked architectures that support constellation-level cooperation, enabling multi…
Quantum Reinforcement Learning for 6G and Beyond Wireless Networks
Dinh-Hieu Tran, Thai Duong Nguyen, Thanh-Dao Nguyen +10
While 5G is being deployed worldwide, 6G is receiving increasing attention from researchers to meet the growing demand for higher data rates, lower latency, higher density, and sea…
Multilayer Non-Terrestrial Networks with Spectrum Access aided by Beyond-Diagonal RIS
Wali Ullah Khan, Chandan Kumar Sheemar, Eva Lagunas +4
In this work, we study a multi-user NTN in which a satellite serves as the primary network and a high-altitude platform station (HAPS) operates as the secondary network, acting as…
Hybrid Table-Assisted and RL-Based Dynamic Routing for NGSO Satellite Networks
Flor Ortiz, Eva Lagunas
This letter investigates dynamic routing in Next-Generation Satellite Orbit (NGSO) constellations and proposes a hybrid strategy that combines precomputed routing tables with a Dee…
In-Lab Carrier Aggregation Testbed for Satellite Communication Systems
Jorge L. Gonzalez-Rios, Eva Lagunas, Hayder Al-Hraishawi +2
Carrier Aggregation (CA) is a technique used in 5G and previous cellular generations to temporarily increase the data rate of a specific user during peak demand periods or to reduc…
DT-Aided Resource Management in Spectrum Sharing Integrated Satellite-Terrestrial Networks
Hung Nguyen-Kha, Vu Nguyen Ha, Ti Ti Nguyen +3
The integrated satellite-terrestrial networks (ISTNs) through spectrum sharing have emerged as a promising solution to improve spectral efficiency and meet increasing wireless dema…
Enhanced Throughput and Seamless Handover Solutions for Urban 5G-Vehicle C-Band Integrated Satellite-Terrestrial Networks
Hung Nguyen-Kha, Vu Nguyen Ha, Eva Lagunas +2
This paper investigates downlink transmission in 5G Integrated Satellite-Terrestrial Networks (ISTNs) supporting automotive users (UEs) in urban environments, where base stations (…
Network Digital Twin for 6G and Beyond: An End-to-End View Across Multi-Domain Network Ecosystems
Dinh-Hieu Tran, Nazar Waheed, Yuris Mulya Saputra +12
With the rapid development of technology, the number of smart mobile users is increasing, accompanied by growing demands from applications such as virtual/augmented reality (VR/XR)…
Swarm Intelligence Optimization of Multi-RIS Aided MmWave Beamspace MIMO
Zaid Abdullah, Mario R. Camana, Abuzar B. M. Adam +3
We investigate the performance of a multiple reconfigurable intelligence surface (RIS)-aided millimeter wave (mmWave) beamspace multiple-input multiple-output (MIMO) system with mu…
Multi-Active RIS-Assisted THz Cell-Free Systems: Spectral and Energy Efficiency Tradeoff
Mario R. Camana, Zaid Abdullah, Carla E. Garcia +3
Reconfigurable intelligent surfaces (RISs) and cell-free massive multiple-input multiple-output (CF-mMIMO) are effective solutions for mitigating large path loss and inter-cell int…
Artificial Intelligence implementation of onboard flexible payload and adaptive beamforming using commercial off-the-shelf devices
Luis Manuel Garcés-Socarrás, Amirhosein Nik, Flor Ortiz +13
Very High Throughput satellites typically provide multibeam coverage, however, a common problem is that there can be a mismatch between the capacity of each beam and the traffic de…
SmartUT: Receive Beamforming for Spectral Coexistence of NGSO Satellite Systems
Almoatssimbillah Saifaldawla, Eva Lagunas, Flor Ortiz +2
In this paper, we investigate downlink co-frequency interference (CFI) mitigation in non-geostationary satellites orbits (NGSOs) co-existing systems. Traditional mitigation techniq…
Survey on Beyond Diagonal RIS Enabled 6G Wireless Networks: Fundamentals, Recent Advances, and Challenges
Wali Ullah Khan, Manzoor Ahmed, Chandan Kumar Sheemar +7
Beyond Diagonal Reconfigurable Intelligent Surfaces (BD-RIS) represent a groundbreaking innovation in sixth-generation (6G) wireless networks, enabling unprecedented control over w…
Enhancing Physical Layer Security in Cognitive Radio-Enabled NTNs with Beyond Diagonal RIS
Wali Ullah Khan, Chandan Kumar Sheemar, Eva Lagunas +1
Beyond diagonal reconfigurable intelligent surfaces (BD-RIS) have emerged as a transformative technology for enhancing wireless communication by intelligently manipulating the prop…
Beyond Diagonal RIS Enhanced Cognitive Radio Enabled Multilayer Non-Terrestrial Networks
Wali Ullah Khan, Chandan Kumar Sheemar, Eva Lagunas +1
Beyond diagonal reconfigurable intelligent surfaces (BD-RIS) have emerged as a transformative technology for enhancing wireless communication by intelligently manipulating the prop…
A Metasurface-based Cross-slot Aperture Coupled Antenna Array for Ku-band Satellites in Reception
Praveen Naidu Vummadisetty, Aral Ertug Zorkun, Juan Andres Vasquez Peralvo +3
The demand for cost-effective, low-profile user terminals for satellite communications supporting multicast services for Geostationary Orbit (GEO) satellites, has become a key focu…