76 citations · 236 across the 57 of their papers we have counts for
59 papers
One-Shot Beam Tracking for Stacked Intelligent Metasurfaces-Assisted LEO Broadcasting
Chandan Kumar Sheemar, Giovanni Iacovelli, Sourabh Solanki +2
This letter develops a physics-informed one-shot beam tracking method for stacked intelligent metasurface (SIM)-enabled low-Earth-orbit (LEO) links with users and an -layer…
Performance Analysis of RSMA-Enabled Bistatic ISAC in LEO Networks with Holographic Apertures and Fluid-Antenna Users
Wali Ullah Khan, Chandan Kumar Sheemar, Muhammad Adil +1
This paper develops an ergodic performance framework for rate-splitting multiple access (RSMA)-enabled bistatic integrated sensing and communication (ISAC) in a low-Earth-orbit (LE…
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…
Joint Average Contiguous Duration of Correlated Fading Envelopes
Muhammad Adil, Syed Junaid Nawaz, Ernestina Cianca +2
Average contiguous duration (ACD) measures the mean time for which a fading envelope remains continuously inside a bounded amplitude interval. This letter extends the concept to tw…
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…
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),…
Stacked Intelligent Metasurfaces Assisted UAV Communications
Chandan Kumar Sheemar, Giovanni Iacovelli, Sourabh Solanki +2
In this paper, we investigate an unmanned aerial vehicle (UAV) communication system assisted by stacked intelligent metasurfaces (SIMs), which enable programmable wave-domain signa…
STAR Beyond Diagonal RISs with Amplification: Modeling and Optimization
Chandan Kumar Sheemar, Giovanni Iacovelli, Wali Ullah Khan +3
This paper develops a physically consistent signal model with hardware constraints for a simultaneous transmitting and reflecting beyond-diagonal RIS (STAR BD-RIS) endowed with per…
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…
A Survey on STAR-RIS Enabled Joint Communications and Sensing: Fundamentals, Recent Advances and Research Challenges
Wali Ullah Khan, Chandan Kumar Sheemar, Syed Tariq Shah +2
The joint communications and sensing (JCAS) paradigm is envisioned as a core capability of sixth-generation (6G) wireless networks, enabling the integration of data communication a…
Resource Allocation and Sharing for UAV-Assisted Integrated TN-NTN with Multi-Connectivity
Abd Ullah Khan, Wali Ullah Khan, Haejoon Jung +1
Unmanned aerial vehicles (UAVs) with multi-connectivity (MC) capabilities efficiently and reliably transfer data between terrestrial networks (TNs) and non-terrestrial networks (NT…
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…
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…
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…
Transmissive Beyond Diagonal RIS-Mounted LEO Communication for NOMA IoT Networks
Wali Ullah Khan, Eva Lagunas, Symeon Chatzinotas
Reconfigurable Intelligent Surface (RIS) technology has emerged as a transformative solution for enhancing satellite networks in next-generation wireless communication. The integra…
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…
Holographic MIMO for Next Generation Non-Terrestrial Networks: Motivation, Opportunities, and Challenges
Giovanni Iacovelli, Chandan Kumar Sheemar, Wali Ullah Khan +4
In this article, we propose the integration of the Holographic Multiple Input Multiple Output (HMIMO) as a transformative solution for next generation Non-Terrestrial Networks (NTN…
Integration of Beyond Diagonal RIS and UAVs in 6G NTNs: Enhancing Aerial Connectivity
Wali Ullah Khan, Eva Lagunas, Asad Mahmood +3
The reconfigurable intelligent surface (RIS) technology shows great potential in sixth-generation (6G) terrestrial and non-terrestrial networks (NTNs) since it can effectively chan…