Results 41 to 50 of about 789 (166)

Downlink transmission and channel estimation for cell-free massive MIMO-OFDM with DSDs

EURASIP Journal on Advances in Signal Processing, 2022
In a cell-free massive MIMO system, multiple users arrive at multiple access points at separate times, while in an OFDM system, different delays can be equivalent to delay spread differences (DSDs).
Yunxiang Guo, Zhenqi Fan, An Lu, Pan Wang, Dongjie Liu, Xinjiang Xia, Dongming Wang   +6 more
doaj   +1 more source

Access Point Switch ON/OFF Strategies for Green Cell-Free Massive MIMO Networking

IEEE Access, 2020
The combination of user-centric network densification and distributed massive multiple-input multiple-output (MIMO) operation has recently brought along a new paradigm in the wireless communications arena, referred to as cell-free massive MIMO networking.
Guillem Femenias, Narjes Lassoued, Felip Riera-Palou   +2 more
doaj   +1 more source

Technology Trends for Massive MIMO towards 6G

Sensors, 2023
At the dawn of the next-generation wireless systems and networks, massive multiple-input multiple-output (MIMO) in combination with leading-edge technologies, methodologies, and architectures are poised to be a cornerstone technology. Capitalizing on its
Yiming Huo, Xingqin Lin, Boya Di, Hongliang Zhang, Francisco Javier Lorca Hernando, Ahmet Serdar Tan, Shahid Mumtaz, Özlem Tuğfe Demir, Kun Chen-Hu   +8 more
doaj   +1 more source

Pilot Power Control for Cell-Free Massive MIMO [PDF]

IEEE Transactions on Vehicular Technology, 2018
In this correspondence paper, we consider a cell-free massive Multiple-Input Multiple-Output (MIMO) system where access points (APs) serve a much smaller number of users under the time-division duplex operation. The APs first estimate the channels via the uplink training phase.
Trang C. Mai, Hien Quoc Ngo, Malcolm Egan, Trung Quang Duong   +3 more
openaire   +2 more sources

Coverage Probability of Cell-Free Massive MIMO Systems [PDF]

2020 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom), 2020
Despite that ongoing and future networks become denser and increasingly irregular, prior works in the area of cell-free (CF) massive multiple-input-multiple-output (mMIMO) systems relied on the strong assumption of uniformly distributed access points (APs).
Anastasios K. Papazafeiropoulos, Pandelis Kourtessis, Marco Di Renzo, Symeon Chatzinotas, John M. Senior   +4 more
openaire   +1 more source

Cell-Free Massive MIMO for Wireless Federated Learning [PDF]

IEEE Transactions on Wireless Communications, 2020
This paper proposes a novel scheme for cell-free massive multiple-input multiple-output (CFmMIMO) networks to support any federated learning (FL) framework. This scheme allows each instead of all the iterations of the FL framework to happen in a large-scale coherence time to guarantee a stable operation of an FL process.
Tung Thanh Vu, Duy Trong Ngo, Nguyen Hoang Tran, Hien Quoc Ngo, Minh Ngoc Dao, Richard H. Middleton   +5 more
openaire   +3 more sources

Towards Cell-Free Massive MIMO: A Measurement-Based Analysis

IEEE Access, 2022
Cell-free widely distributed massive multiple-input multiple-output (MIMO) systems utilize radio units spread out over a large geographical area. The radio signal of a user equipment (UE) is coherently detected by a subset of radio units (RUs) in the ...
David Loschenbrand, Markus Hofer, Laura Bernado, Stefan Zelenbaba, Thomas Zemen   +4 more
doaj   +1 more source

On the Total Energy Efficiency of Cell-Free Massive MIMO [PDF]

IEEE Transactions on Green Communications and Networking, 2018
We consider the cell-free massive multiple-input multiple-output (MIMO) downlink, where a very large number of distributed multiple-antenna access points (APs) serve many single-antenna users in the same time-frequency resource. A simple (distributed) conjugate beamforming scheme is applied at each AP via the use of local channel state information (CSI)
Hien Quoc Ngo, Le-Nam Tran, Trung Quang Duong, Michail Matthaiou, Erik G. Larsson   +4 more
openaire   +3 more sources

Fundamental Challenges, Physical Implementations, and Integration Strategies for Ising Machines in Large‐Scale Optimization Tasks

Advanced Electronic Materials, EarlyView.
Ising machines are emerging as specialized hardware solvers for computationally hard optimization problems. This review examines five major platforms—digital CMOS, analog CMOS, emerging devices, coherent optics, and quantum systems—highlighting physics‐rooted advantages and shared bottlenecks in scalability and connectivity.
Hyunjun Lee, Joon Pyo Kim, Sanghyeon Kim
wiley   +1 more source

Low‐Complexity Hybrid Beamforming for LEO Satellites: Beam Update Rate Analysis and Advanced Adaptive Precoding

International Journal of Satellite Communications and Networking, EarlyView.
ABSTRACT Low Earth Orbit (LEO) satellite constellations offer unprecedented opportunities for global broadband connectivity but pose significant beamforming challenges due to rapid platform motion and stringent onboard hardware constraints. Fully digital architectures, while optimal in theory, remain impractical for satellite payloads, motivating ...
Mohammad Momani, Thomas Delamotte, Andreas Knopp   +2 more
wiley   +1 more source