Near-field Hybrid Beamforming for Terahertz-band Integrated Sensing and Communications

TL;DR

This paper introduces an alternating optimization method for hybrid beamforming in near-field Terahertz ISAC systems, effectively compensating beam-squint and enhancing spectral efficiency without extra hardware.

Contribution

It presents a novel near-field hybrid beamforming design and a beam-squint compensation approach tailored for THz-ISAC systems, addressing limitations of prior far-field models.

Findings

Achieves high spectral efficiency in near-field THz-ISAC scenarios.

Accurately estimates near-field beamformers and mitigates beam-squint.

Operates without additional hardware components.

Abstract

Terahertz (THz) band communications and integrated sensing and communications (ISAC) are two main facets of the sixth generation wireless networks. In order to compensate the severe attenuation, the THz wireless systems employ large arrays, wherein the near-field beam-squint severely degrades the beamforming accuracy. Contrary to prior works that examine only either narrowband ISAC beamforming or far-field models, we introduce an alternating optimization technique for hybrid beamforming design in near-field THz-ISAC scenario. We also propose an efficient approach to compensate near-field beam-squint via baseband beamformers. Via numerical simulations, we show that the proposed approach achieves satisfactory spectral efficiency performance while accurately estimating the near-field beamformers and mitigating the beam-squint without additional hardware components.