In this paper, a practical non-stationary three-dimensional (3-D) channel models for massive multiple-input multiple-output (MIMO) systems, considering beam patterns for different antenna elements, is proposed. The beam patterns using dipole antenna elements with different phase excitation toward the different direction of travels (DoTs) contributes various correlation weights for rays related towards/from the cluster, thus providing different elevation angle of arrivals (EAoAs) and elevation angle of departures (EAoDs) for each antenna element. These include the movements of the user that makes our channel to be a non-stationary model of clusters at the receiver (RX) on both the time and array axes. In addition, their impacts on 3-D massive MIMO channels are investigated via statistical properties including received spatial correlation. Additionally, the impact of elevation/azimuth angles of arrival on received spatial correlation is discussed. Furthermore, experimental validation of the proposed 3-D channel models on azimuth and elevation angles of the polarized antenna are specifically evaluated and compared through simulations. The proposed 3-D generic models are verified using relevant measurement data.
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http://dx.doi.org/10.3390/s18041186 | DOI Listing |
Nat Commun
January 2025
Institute of Electromagnetic Space, Southeast University, Nanjing, China.
Holographic multiple-input multiple-output (MIMO) method leverages spatial diversity to enhance the performance of wireless communications and is expected to be a key technology enabling for high-speed data services in the forthcoming sixth generation (6G) networks. However, the antenna array commonly used in the traditional massive MIMO cannot meet the requirements of low cost, low complexity and high spatial resolution simultaneously, especially in higher frequency bands. Hence it is important to achieve a feasible hardware platform to support theoretical study of the holographic MIMO communications.
View Article and Find Full Text PDFPLoS One
January 2025
CICESE, Ensenada, Baja California, Mexico.
The 5G network was developed to push the capabilities of wireless networks to previously unseen performance limits, e.g., transmission rates of several gigabits per second, latency of less than a millisecond, and millions of devices connected at the same time.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Electronics & Communication, University of Allahabad, Prayagraj, UP, India.
In this article an 8-port annular ring-shaped MIMO antenna for 5G and 5G advanced applications is presented. An annular ring on the radiating plane and novel isolator structure on the ground plane are etched over a Rogers RT/Duorid (5870 tm) substrate to achieve high performance antenna for mm wave applications. A systematic study is performed, and an optimized single port antenna (Design-4) is selected among Designs (1-4).
View Article and Find Full Text PDFSensors (Basel)
November 2024
Department of Digital Industry Technologies, National and Kapodistrian University of Athens, Dirfies Messapies, 34400 Athens, Greece.
The goal of the study presented in this work is to evaluate the performance of a proposed adaptive beamforming approach when combined with non-orthogonal multiple access (NOMA) in cell-free massive multiple input multiple output (CF m-MIMO) orientations. In this context, cooperative beamforming is employed taking into consideration the geographically adjacent access points (APs) of a virtual cell, aiming to minimize co-channel interference (CCI) among mobile stations (MSs) participating in NOMA transmission. Performance is evaluated statistically via extensive Monte Carlo (MC) simulations in a two-tier wireless orientation.
View Article and Find Full Text PDFSensors (Basel)
November 2024
PLA Army Engineering University, Nanjing 210007, China.
In a cell-free massive multiple-input multiple-output (MIMO) system without cells, it is assumed that there are smart jammers and disrupters (SJDs) that attempt to interfere with and eavesdrop on the downlink communications of legitimate users. A secure transmission scheme based on multiple intelligent reflecting surfaces (IRSs) and artificial noise (AN) is proposed. First, an access point (AP) selection strategy based on user location information is designed, which aims to determine the set of APs serving users.
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