Full dimension (FD) multiple-input multiple-output (MIMO) technology has attracted substantial research attention from both wireless industry and academia in the last few years as a promising technique for next-generation wireless communication networks. FD-MIMO scenarios utilize a planar 2-D active antenna system (AAS) that not only allows a large number of antenna elements to be placed within feasible base station (BS) form factors, but also provides the ability of adaptive electronic beam control over both the elevation and the traditional azimuth dimensions. This paper presents a tutorial on elevation beamforming analysis for cellular networks utilizing FD massive MIMO antenna arrays. In contrast to existing works that focus on the standardization of FD-MIMO in the 3rd generation partnership project (3GPP), this tutorial is distinguished by its depth with respect to the theoretical aspects of antenna array and 3-D channel modeling. In an attempt to bridge the gap between industry and academia, this preliminary tutorial introduces the relevant array and transceiver architecture designs proposed in the 3GPP Release 13 that enable elevation beamforming. Then it presents and compares two different 3-D channel modeling approaches that can be utilized for the performance analysis of elevation beamforming techniques. The spatial correlation in FD-MIMO arrays is characterized and compared based on both channel modeling approaches and some insights into the impact of different channel and array parameters on the correlation are drawn. All these aspects are put together to provide a mathematical framework for the design of elevation beamforming schemes in single-cell and multi-cell scenarios. Simulation examples associated with comparisons and discussions are also presented. To this end, this paper highlights the state-of-the-art research and points out future research directions.

中文翻译：

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在 5G 系统中使用全维 MIMO 架构进行仰角波束成形：教程

全维 (FD) 多输入多输出 (MIMO) 技术作为下一代无线通信网络的有前途的技术，在过去几年中引起了无线行业和学术界的大量研究关注。FD-MIMO 场景利用平面 2-D 有源天线系统 (AAS)，该系统不仅允许将大量天线元件放置在可行的基站 (BS) 外形因素内，而且还提供自适应电子波束控制能力仰角和传统的方位角尺寸。本文介绍了使用 FD 大规模 MIMO 天线阵列的蜂窝网络的仰角波束成形分析教程。与第三代合作伙伴计划 (3GPP) 中专注于 FD-MIMO 标准化的现有工作相比，本教程以其在天线阵列和 3-D 通道建模理论方面的深度而著称。为了弥合工业界和学术界之间的鸿沟，本初步教程介绍了 3GPP 第 13 版中提出的相关阵列和收发器架构设计，这些设计支持仰角波束成形。然后，它提出并比较了两种不同的 3-D 通道建模方法，这些方法可用于高程波束成形技术的性能分析。基于两种信道建模方法表征和比较了 FD-MIMO 阵列中的空间相关性，并得出了对不同信道和阵列参数对相关性影响的一些见解。所有这些方面结合在一起，为单小区和多小区场景中的高程波束成形方案的设计提供了一个数学框架。还介绍了与比较和讨论相关的模拟示例。为此，本文重点介绍了最新研究成果，并指出了未来的研究方向。