scholarly journals Research of antenna complexes using chiral metamaterials and fractal geometry of radiators for MIMO systems

2021 ◽  
Vol 23 (4) ◽  
pp. 97-110
Author(s):  
Andrey N. Bespalov ◽  
Alexander L. Buzov ◽  
Dmitry S. Klyuev ◽  
Anatoly M. Neshcheret
Keyword(s):  
Spectral Efficiency ◽  
Fractal Geometry ◽  
Software Package ◽  
Mimo Systems ◽  
Mutual Influence ◽  
Fractal Structures ◽  
Chiral Metamaterials ◽  
Sierpinski Triangle ◽  
Electrodynamic Modeling ◽  
Complete Matrix

This article is devoted to the study of the possibilities of increasing spectral efficiency in MIMO systems by using antennas with substrates of biisotropic and bianisotropic chiral metamaterials and various types of fractal emitters, in particular, fractal structures in the form of a Sierpinski triangle, Koch and Gilbert curves, as well as a dipole triangular antenna of complex configuration FRM. The spectral efficiency was calculated by using one of the variations of the Shannon formula, which includes a complete matrix of Z-parameters. In turn, this matrix was determined using the software package of electrodynamic modeling. It is shown that the use of such antennas with the fractal geometry of the emitters located on chiral substrates reduces the mutual influence between the emitters, and, in turn, increases the spectral efficiency in several frequency ranges compared to traditional solutions.

scholarly journals Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xiao Chen ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Jian Dang
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Mimo Systems ◽  
Beam Steering ◽  
Estimation Method ◽  
Low Complexity ◽  
Estimation Accuracy ◽  
Hybrid Architecture

Abstract In this journal, we investigate the beam-domain channel estimation and power allocation in hybrid architecture massive multiple-input and multiple-output (MIMO) communication systems. First, we propose a low-complexity channel estimation method, which utilizes the beam steering vectors achieved from the direction-of-arrival (DOA) estimation and beam gains estimated by low-overhead pilots. Based on the estimated beam information, a purely analog precoding strategy is also designed. Then, the optimal power allocation among multiple beams is derived to maximize spectral efficiency. Finally, simulation results show that the proposed schemes can achieve high channel estimation accuracy and spectral efficiency.

scholarly journals Quasi-Distributed Antenna Selection for Spectral Efficiency Maximization in Subarray Switching XL-MIMO Systems

2021 ◽  
pp. 1-1
Author(s):  
Joao Henrique Inacio De Souza ◽  
Abolfazl Amiri ◽  
Taufik Abrao ◽  
Elisabeth De Carvalho ◽  
Petar Popovski
Keyword(s):  
Spectral Efficiency ◽  
Mimo Systems ◽  
Antenna Selection ◽  
Distributed Antenna ◽  
Selection For

scholarly journals Pencil and Shaped Beam Patterns Synthesis Using a Hybrid GA/l₁ Optimization and Its Application to Improve Spectral Efficiency of Massive MIMO Systems

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 38202-38220
Author(s):  
Samar Ibrahim Farghaly ◽  
Hussein Eltaibee Seleem ◽  
Mustafa Mahmoud Abd-Elnaby ◽  
Amr Hussein Hussein
Keyword(s):  
Spectral Efficiency ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Shaped Beam ◽  
Beam Patterns

scholarly journals An Evaluation of Successive Pilot Decontamination in Massive MIMO

2018 ◽  
Vol 39 (2) ◽  
pp. 107
Author(s):  
Victor Croisfelt Rodrigues ◽  
Taufik Abrão
Keyword(s):  
Spectral Efficiency ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Pilot Training ◽  
Pilot Contamination ◽  
Fundamental Issue ◽  
Data Rates ◽  
Multiple Input ◽  
Input Multiple Output

The demand for higher data rates can be satisfied by the spectral efficiency (SE) improvement offered by Massive multiple-input multiple-output (M-MIMO) systems. However, the pilot contamination remains as a fundamental issue to obtain the paramount SE in such systems. This propitiated the research of several methods to mitigate pilot contamination. One of these procedures is based on the coordination of the cells, culminating in proposals with multiple pilot training phases. This paper aims to expand the results of the original paper, whereby the concepts of large pilot training phases were offered. The evaluation of such method was conducted through more comprehensible numerical results, in which a large number of antennas were assumed and more rigorous SE expressions were used. The channel estimation approaches relying on multiple pilot training phases were considered cumbersome for implementation and an uninteresting solution to overcome pilot contamination; contradicting the results presented in the genuine paper.

scholarly journals Joint Pilot Allocation and Power Control to Enhance Max-Min Spectral Efficiency in TDD Massive MIMO Systems

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 149191-149201 ◽  
Author(s):  
Gang Liu ◽  
Honggui Deng ◽  
Xuewen Qian ◽  
Wenhui Wang ◽  
Gaofeng Peng
Keyword(s):  
Power Control ◽  
Spectral Efficiency ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Pilot Allocation
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