Two-Stage Hybrid Transceiver Design Relying on Low-Resolution ADCs in Partially Connected MU Terahertz (THz) MIMO Systems

TL;DR

This paper proposes a two-stage hybrid transceiver design for low-resolution MU THz MIMO systems, addressing dual-wideband effects with a novel beamforming approach using true time delay lines, resulting in improved spectral efficiency.

Contribution

It introduces a new transceiver architecture and beamforming method that effectively mitigates dual-wideband effects in low-resolution THz MIMO systems.

Findings

Achieves approximately 13% spectral efficiency improvement.

Models THz MIMO channels considering absorption, reflection, and free-space losses.

Employs true time delay lines to eliminate beam-split effects.

Abstract

A two-stage hybrid transceiver is designed by considering a partially connected architecture at the base station (BS) for a low-resolution multi-user (MU) THz massive multiple input multiple output (MIMO) system. Due to its high bandwidth coupled with a high number of antennas, the THz band suffers from the deleterious spatial-wideband and frequency-wideband effects jointly termed as the dual-wideband effect. To address this undesired phenomenon, we rigorously model the THz MIMO channel at each subarray corresponding to each user by incorporating the absorption, reflection, and free-space losses. Subsequently, a novel beamforming technique is proposed that employs only a few true time delay (TTD) lines for eliminating the beam-split effect, which is the manifestation of the spatial-wideband effect in the frequency domain. Our simulation results demonstrate a performance improvement of around 13% in terms of spectral efficiency over the existing state-of-the-art techniques.