3 citations · 14 across the 41 of their papers we have counts for
15 papers · 1 filter
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…
Joint Communications, Sensing, and Positioning in 6G Multi-Functional Satellite Systems: Survey and Open Challenges
Chandan Kumar Sheemar, Jorge Querol, Wali Ullah Khan +7
Satellite systems are expected to be a cornerstone of sixth-generation (6G) networks, providing ubiquitous coverage and supporting a wide range of services across communications, s…
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…
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…
RIS-based Physical Layer Security for Integrated Sensing and Communication: A Comprehensive Survey
Yongxiao Li, Feroz Khan, Manzoor Ahmed +5
Integrated Sensing and Communication (ISAC) is a crucial component of future wireless networks, enabling seamless integration of Communication and Sensing (C\&S) functionalities. H…
Minimum Mean Squared Error Holographic Beamforming for Sum-Rate Maximization
Chandan Kumar Sheemar, Wali Ullah Khan, George C. Alexandropoulos +2
This paper studies the problem of hybrid holographic beamforming for sum-rate maximization in a communication system assisted by a reconfigurable holographic surface. Existing meth…
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…
Secrecy Rate Maximization for 6G Reconfigurable Holographic Surfaces Assisted Systems
Chandan Kumar Sheemar, Wali Ullah Khan, Marco di Renzo +3
Reconfigurable holographic surfaces (RHS) have emerged as a transformative material technology, enabling dynamic control of electromagnetic waves to generate versatile holographic…
Joint Beamforming and 3D Location Optimization for Multi-User Holographic UAV Communications
Chandan Kumar Sheemar, Asad Mahmood, Christo Kurisummoottil Thomas +4
This paper pioneers the field of multi-user holographic unmanned aerial vehicle (UAV) communications, laying a solid foundation for future innovations in next-generation aerial wir…
Joint Holographic Beamforming and User Scheduling with Individual QoS Constraints
Chandan Kumar Sheemar, Christo Kurisummoottil Thomas, George C. Alexandropoulos +3
Reconfigurable holographic surfaces (RHS) have emerged as a transformative material technology, enabling dynamic control of electromagnetic waves to generate versatile holographic…
Holographic Joint Communications and Sensing With Cramer-Rao Bounds
Chandan Kumar Sheemar, Wali Ullah Khan, George Alexandropoulos +2
Joint Communication and Sensing (JCAS) technology facilitates the seamless integration of communication and sensing functionalities within a unified framework, enhancing spectral e…
Beyond Diagonal RIS: A New Frontier for 6G Internet of Things Networks
Wali Ullah Khan, Chandan Kumar Sheemar, Eva Lagunas +1
Reconfigurable intelligent surface (RIS) technology has emerged as a promising enabler for next-generation wireless networks, offering a paradigm shift from passive environments to…
Joint Communications and Sensing for 6G Satellite Networks: Use Cases and Challenges
Chandan Kumar Sheemar, Prabhu Thiruvasagam, Wali Ullah Khan +6
Satellite networks (SN) have long provided two fundamental services: global communications and Earth-oriented sensing, supporting applications from connectivity and navigation to d…