Results 71 to 80 of about 789 (166)

On the Performance of Downlink Channel Estimation‐Based Cell‐Free Massive MIMO Systems Under Correlated Rician Fading Channels

Engineering Reports
The prevailing research on cell‐free massive multiple‐input multiple‐output (MIMO) systems posits that, due to channel reciprocity and channel hardening properties, user equipment (UEs) can decode downlink data solely based on uplink statistical channel ...
Jiarui Li, Yao Zhang, Fengjiao Gan, Na Liu, Longxiang Yang, Hongbo Zhu   +5 more
doaj   +1 more source

Cell-Free Massive MIMO

, 2018
Cell-free massive multiple-input multiple-output (MIMO) is a system comprising a very large number of access points (hundreds or thousands of access points) and a relatively smaller number of active users (tens or hundreds of users) distributed over a large area. The access points use directly measured channel characteristics to jointly serve all users
openaire   +2 more sources

Millisecond‐Switching Dual‐Band/Dual‐Polarization Ka‐Band Wavefront Control Enabled by a Complementary Liquid‐Crystal Metasurface

Advanced Materials Technologies, Volume 11, Issue 4, 19 February 2026.
An LCD‐compatible complementary liquid‐crystal metasurface delivers dual‐band, dual‐polarized Ka‐band wavefront control with millisecond switching via a 10‐µm LC gap. Interlaced patch/slot pairs enable independent phase tuning at 28 and 38 GHz, while strategic 45° slot rotation suppresses parasitic resonances. Measurements on a 160 × 160‐cell prototype
Daehyeon Kim, Donggeun An, Hyunjae Shin, Youngno Youn, Wonbin Hong   +4 more
wiley   +1 more source

CNN-Based End-to-End CPU-AP-UE Power Allocation for Spectral Efficiency Enhancement in Cell-Free Massive MIMO Networks

Mathematics
Cell-free massive multiple-input multiple-output (MIMO) networks eliminate cell boundaries and enhance uniform quality of service by enabling cooperative transmission among access points (APs). In conventional cellular networks, user equipment located at
Yoon-Ju Choi, Ji-Hee Yu, Seung-Hwan Seo, Seong-Gyun Choi, Hye-Yoon Jeong, Ja-Eun Kim, Myung-Sun Baek, Young-Hwan You, Hyoung-Kyu Song   +8 more
doaj   +1 more source

Robust Spectral and Energy Efficiency Tradeoff for RIS‐Aided Multi‐User Communication

IET Communications, Volume 20, Issue 1, January/December 2026.
In this work, an RIS‐aided multi‐user network with imperfect CSI is investigated. Correspondingly, we focus on balancing SE and EE through the collaborative design of the base station (BS)'s precoding matrix and the RIS's phase shifts, which consider the transmit power budget and the channel uncertainties constraints.
Xiandeng He, Yilin Wang, Shun Zhang
wiley   +1 more source

A Massive Grant‐Free Random Access Scheme Based on Spectrum Sensing and Preamble Delay

IET Communications, Volume 20, Issue 1, January/December 2026.
This paper introduces cognitive radio (CR) and preamble delay (PD) to reduce access collisions, together with non‐orthogonal multiple access (NOMA) to improve spectrum efficiency, and thus proposes an efficient CR‐NOMA‐PD‐based massive grant‐free random multiple access scheme.
Jing Zhang, Zhuang‐Zhuang Wei, Yu‐Qi Zhang, Hong‐Xu Gao, Hai‐Tao Zhao, Hong‐Bo Zhu   +5 more
wiley   +1 more source

Regularised Hyper Parameter Bi Level Optimisation With Continual Learning Based Deep Neural Network for Beamforming in Ultra‐Wide Band System

IET Communications, Volume 20, Issue 1, January/December 2026.
This research proposes a Regularised Hyperparameter Bilevel Optimisation with Continual Learning‐based Deep Neural Network (RHBO‐CLDNN) for beamforming in an Ultra‐Wide Band (UWB) system. The RHBO ensures the hyperparameter efficiency at both upper and lower levels, which allows DNN to fine‐tune the unique characteristics of the UWB system, which leads
Pradeep Kumar Siddanna, Bidare Divakarachari Parameshachari, Dharmanna Shivappa Lamani   +2 more
wiley   +1 more source

Closed‐Form Approximation of Average Error Probability With Finite‐Blocklength Coding Over Lognormal Wireless Communication Links

IET Communications, Volume 20, Issue 1, January/December 2026.
This work extends the Polyanskiy‐Poor‐Verdu (PPV) framework to lognormal wireless links. Specifically, the paper derives a closed‐form approximation for the average error probability under lognormal distribution, effectively generalizing the PPV analysis beyond the additive white Gaussian noise assumption.
Peng Du, Yuan Zhang
wiley   +1 more source

A Comparative Benchmark of Scale-Up and Scale-Out MIMO Architectures for 5G and Prospective 6G Networks

Telecom
The evolution toward prospective sixth-generation (6G) wireless networks is expected to significantly increase user density, bandwidth demand, and architectural complexity, reinforcing the need for scalable multiple-input multiple-output (MIMO ...
Samuel Otero Rebolo, Victor Monzon Baeza
doaj   +1 more source

Energy‐Efficient Element Selection in RIS‐Assisted Backscatter Communication Systems

IET Communications, Volume 20, Issue 1, January/December 2026.
This paper investigates energy‐efficient reconfigurable intelligent surface (RIS) assisted ambient backscatter communication systems with energy‐harvesting tags. A low‐complexity RIS element selection strategy is developed to satisfy both energy‐harvesting and signal‐to‐interference‐plus‐noise ratio constraints while minimizing overall power ...
Mengistu A. Mulatu, Thembelihle Dlamini, Asrat M. Beyene   +2 more
wiley   +1 more source