3D massive MIMO with massive connectivity for internet of things devices.

Three-dimensional massive multiple-input multiple-output (3D Massive MIMO) with a large number of small antennas embedded in a uniformly rectangular antenna array provides a significant improvement in the system’s bandwidth and energy efficiency. In this paper, we analyze the possible connectivity of internet of things (IoT) devices wirelessly through the applicability of 3D massive MIMO systems. A single-cell 3D massive MIMO system has been established to support a considerable number of IoT devices in the downlink. We provide detailed channel model for tranmission in azimuthal domain and elevation domain and framework and equations of bandwidth efficiency (BE) and energy efficiency for maximum ratio, zero-forcing, and improved zero-forcing (IZF) with enhanced connectivity. Meanwhiel, We also analyze the BE for the three precoding schemes by varying single-to-noise, angular spread, and the number of IoT users. Comprehensive simulations are performed by apply several antenna configuraions i.e. 8×8\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$8 \times 8$$\end{document}, 16×16\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$16 \times 16$$\end{document} and 32×32\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$32 \times 32$$\end{document}. Simulation results validate that, the derived IZF provides better results in terms of bandwidth and energy efficiency. Meanwhile, we emphasize that 3D massive MIMO is one of the most suitable ways to connect IoT devices wirelessly. [ABSTRACT FROM AUTHOR]