Terahertz (THz)-band communications are currently being celebrated as a key technology that could fulfill the increasing demands for wireless data traffic in 6G wireless communications. Many challenges, such as high propagation losses and power limitations, which result in short communication distances, have yet to be addressed for this technology to be realized. Ultramassive multiple-input, multiple-output (UMMIMO) antenna systems have emerged as practical means for combatting this distance problem, thereby increasing system capacity. Toward that end, graphene-based nanoantennas have recently been proposed, as they can be individually tuned and collectively controlled in compact UM-MIMO array-of-subarrays (AoSA) architectures. In this article, we present a holistic overview of THz UM-MIMO systems. We assess recent advancements in transceiver design and channel modeling and discuss the major challenges and shortcomings of such designs by deriving the relationships among communication range, array dimensions, and system performance. We further highlight several research advances that could enhance resource allocation at the THz band, including waveform designs, multicarrier configurations, and spatial modulations (SMs). Based on this discussion, we highlight prospective use cases that can bring THz UM-MIMO into reality in the context of sensing, data centers, cell-free systems, and mid-range wireless communications.

中文翻译：

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太赫兹频段的超大规模 MIMO 系统：前景与挑战

太赫兹 (THz) 频段通信目前被认为是一项关键技术，可以满足 6G 无线通信中对无线数据流量日益增长的需求。许多挑战，例如高传播损耗和功率限制，导致通信距离短，尚未解决该技术的实现。超大规模多输入多输出 (UMMIMO) 天线系统已成为解决这一距离问题的实用手段，从而提高系统容量。为此，最近提出了基于石墨烯的纳米天线，因为它们可以在紧凑的 UM-MIMO 子阵列阵列 (AoSA) 架构中单独调整和集体控制。在本文中，我们全面概述了 THz UM-MIMO 系统。我们评估了收发器设计和信道建模的最新进展，并通过推导通信范围、阵列尺寸和系统性能之间的关系来讨论此类设计的主要挑战和缺点。我们进一步强调了可以增强太赫兹频段资源分配的几项研究进展，包括波形设计、多载波配置和空间调制 (SM)。基于此讨论，我们重点介绍了可以在传感、数据中心、无蜂窝系统和中距离无线通信环境中将太赫兹 UM-MIMO 变为现实的前瞻性用例。我们进一步强调了一些可以增强太赫兹频段资源分配的研究进展，包括波形设计、多载波配置和空间调制 (SM)。基于此讨论，我们重点介绍了可以在传感、数据中心、无蜂窝系统和中距离无线通信环境中将太赫兹 UM-MIMO 变为现实的前瞻性用例。我们进一步强调了一些可以增强太赫兹频段资源分配的研究进展，包括波形设计、多载波配置和空间调制 (SM)。基于此讨论，我们重点介绍了可以在传感、数据中心、无蜂窝系统和中距离无线通信环境中将太赫兹 UM-MIMO 变为现实的前瞻性用例。