Beamforming Technologies for Ultra-Massive MIMO in Terahertz Communications

Boyu Ning; Zhongbao Tian; Weidong Mei; Zhi Chen; Chong Han; Shaoqian Li; Jinhong Yuan; Rui Zhang

doi:10.1109/OJCOMS.2023.3245669

IEEE Open Journal of the Communications Society (Jan 2023)

Beamforming Technologies for Ultra-Massive MIMO in Terahertz Communications

Boyu Ning,
Zhongbao Tian,
Weidong Mei,
Zhi Chen,
Chong Han,
Shaoqian Li,
Jinhong Yuan,
Rui Zhang

Affiliations

Boyu Ning: ORCiD; National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu, China
Zhongbao Tian: ORCiD; National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu, China
Weidong Mei: ORCiD; National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu, China
Zhi Chen: ORCiD; National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu, China
Chong Han: ORCiD; Terahertz Wireless Communications Laboratory, Shanghai Jiao Tong University, Shanghai, China
Shaoqian Li: National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu, China
Jinhong Yuan: ORCiD; School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, Australia
Rui Zhang: ORCiD; Shenzhen Research Institute of Big Data, The Chinese University of Hong Kong (Shenzhen), Shenzhen, China

DOI: https://doi.org/10.1109/OJCOMS.2023.3245669
Journal volume & issue: Vol. 4
pp. 614 – 658

Abstract

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Terahertz (THz) communications with a frequency band 0.1 – 10 THz are envisioned as a promising solution to future high-speed wireless communication. Although with tens of gigahertz available bandwidth, THz signals suffer from severe free-spreading loss and molecular-absorption loss, which limit the wireless transmission distance. To compensate for the propagation loss, the ultra-massive multiple-input-multiple-output (UM-MIMO) can be applied to generate a high-gain directional beam by beamforming technologies. In this paper, a review of beamforming technologies for THz UM-MIMO systems is provided. Specifically, we first present the system model of THz UM-MIMO and identify its channel parameters and architecture types. Then, we illustrate the basic principles of beamforming via UM-MIMO and discuss the far-field and near-field assumptions in THz UM-MIMO. Moreover, an important beamforming strategy in THz band, i.e., beam training, is introduced wherein the beam training protocol and codebook design approaches are summarized. The intelligent-reflecting-surface (IRS)-assisted joint beamforming and multi-user beamforming in THz UM-MIMO systems are studied, respectively. The spatial-wideband effect and frequency-wideband effect in the THz beamforming are analyzed and the corresponding solutions are provided. Further, we present the corresponding fabrication techniques and illuminate the emerging applications benefiting from THz beamforming. Open challenges and future research directions on THz UM-MIMO systems are finally highlighted.

Published in IEEE Open Journal of the Communications Society

ISSN: 2644-125X (Online)
Publisher: IEEE
Country of publisher: United States
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Telecommunication; Social Sciences: Transportation and communications
Website: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8782661

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