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arXiv · 2303.12466

Beam Squint Analysis and Mitigation via Hybrid Beamforming Design in THz Communications

Mengyuan Ma·Nhan Thanh Nguyen·Markku Juntti
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Abstract

We investigate the beam squint effect in uniform planar arrays (UPAs) and propose an efficient hybrid beamforming (HBF) design to mitigate the beam squint in multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems operating at terahertz band. We first analyze the array gain and derive the closed-form beam squint ratio that characterizes the severity of the beam squint effect on UPAs. The effect is shown to be more severe with a higher fractional bandwidth, while it can be significantly mitigated when the shape of a UPA approaches a square. We then focus on the HBF design that maximizes the system spectral efficiency. The design problem is challenging due to the frequency-flat nature and hardware constraints of the analog beamformer. We overcome the challenges by proposing an efficient decoupling design in which the digital and analog beamformers admit closed-form solutions, which facilitate practical implementations. Numerical results validate our analysis and show that the proposed HBF design is robust to beam squint, and thus, it outperforms the state-of-the-art methods in wideband massive MIMO systems.

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Mengyuan Ma, Nhan Thanh Nguyen, Markku Juntti. 2023-03-22. Beam Squint Analysis and Mitigation via Hybrid Beamforming Design in THz Communications. https://doi.org/10.1109/icc45041.2023

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