Enhancing Indoor and Outdoor THz Communications with Beyond Diagonal-IRS: Optimization and Performance Analysis

Fuente: arXiv
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Main Authors: Mahmood, Asad, Vu, Thang X., Chatzinotas, Symeon, Ottersten, Björn
Format: Preprint
Published: 2024
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author Mahmood, Asad
Vu, Thang X.
Chatzinotas, Symeon
Ottersten, Björn
author_facet Mahmood, Asad
Vu, Thang X.
Chatzinotas, Symeon
Ottersten, Björn
contents This work investigates the application of Beyond Diagonal Intelligent Reflective Surface (BD-IRS) to enhance THz downlink communication systems, operating in a hybrid: reflective and transmissive mode, to simultaneously provide services to indoor and outdoor users. We propose an optimization framework that jointly optimizes the beamforming vectors and phase shifts in the hybrid reflective/transmissive mode, aiming to maximize the system sum rate. To tackle the challenges in solving the joint design problem, we employ the conjugate gradient method and propose an iterative algorithm that successively optimizes the hybrid beamforming vectors and the phase shifts. Through comprehensive numerical simulations, our findings demonstrate a significant improvement in rate when compared to existing benchmark schemes, including time- and frequency-divided approaches, by approximately $30.5\%$ and $69.9\%$ respectively and even outperforms the STAR-IRS system by $76.99\%$. This underscores the significant influence of IRS elements on system performance relative to that of base station antennas, highlighting their pivotal role in advancing the communication system efficacy.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17913
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Enhancing Indoor and Outdoor THz Communications with Beyond Diagonal-IRS: Optimization and Performance Analysis
Mahmood, Asad
Vu, Thang X.
Chatzinotas, Symeon
Ottersten, Björn
Signal Processing
This work investigates the application of Beyond Diagonal Intelligent Reflective Surface (BD-IRS) to enhance THz downlink communication systems, operating in a hybrid: reflective and transmissive mode, to simultaneously provide services to indoor and outdoor users. We propose an optimization framework that jointly optimizes the beamforming vectors and phase shifts in the hybrid reflective/transmissive mode, aiming to maximize the system sum rate. To tackle the challenges in solving the joint design problem, we employ the conjugate gradient method and propose an iterative algorithm that successively optimizes the hybrid beamforming vectors and the phase shifts. Through comprehensive numerical simulations, our findings demonstrate a significant improvement in rate when compared to existing benchmark schemes, including time- and frequency-divided approaches, by approximately $30.5\%$ and $69.9\%$ respectively and even outperforms the STAR-IRS system by $76.99\%$. This underscores the significant influence of IRS elements on system performance relative to that of base station antennas, highlighting their pivotal role in advancing the communication system efficacy.
title Enhancing Indoor and Outdoor THz Communications with Beyond Diagonal-IRS: Optimization and Performance Analysis
topic Signal Processing
url https://arxiv.org/abs/2403.17913