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Bibliographic Details
Main Authors: Li, Luchu, Zhi, Kangda, Pan, Cunhua
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.07699
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author Li, Luchu
Zhi, Kangda
Pan, Cunhua
author_facet Li, Luchu
Zhi, Kangda
Pan, Cunhua
contents This paper proposes a two-timescale transmission scheme for extremely large-scale (XL)-reconfigurable intelligent surfaces (RIS)-aided massive multi-input multi-output (MIMO) systems considering visibility regions (VRs). The beamforming of base stations (BS) is designed based on rapidly changing instantaneous channel state information (CSI), while the phase shifts of RIS are configured based on slowly changing statistical CSI. Specifically, we first formulate a system model with spatially correlated Rician fading channels and introduce the concept of VRs. Then, we derive a closed-form approximate expression for the achievable rate applicable to any number of BS antennas and RIS elements, and analyze the impact of VRs on system performance and complexity. Next, we solve the problem of maximizing the minimum user rate by optimizing the phase shifts of RIS through an algorithm based on accelerated gradient ascent. Finally, we present numerical results to demonstrate the performance of the gradient algorithm from different aspects and reveal the low system complexity of deploying XL-RIS in massive MIMO systems with the help of VRs.
format Preprint
id arxiv_https___arxiv_org_abs_2407_07699
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transmission Design for XL-RIS-Aided Massive MIMO System with Visibility Regions
Li, Luchu
Zhi, Kangda
Pan, Cunhua
Information Theory
This paper proposes a two-timescale transmission scheme for extremely large-scale (XL)-reconfigurable intelligent surfaces (RIS)-aided massive multi-input multi-output (MIMO) systems considering visibility regions (VRs). The beamforming of base stations (BS) is designed based on rapidly changing instantaneous channel state information (CSI), while the phase shifts of RIS are configured based on slowly changing statistical CSI. Specifically, we first formulate a system model with spatially correlated Rician fading channels and introduce the concept of VRs. Then, we derive a closed-form approximate expression for the achievable rate applicable to any number of BS antennas and RIS elements, and analyze the impact of VRs on system performance and complexity. Next, we solve the problem of maximizing the minimum user rate by optimizing the phase shifts of RIS through an algorithm based on accelerated gradient ascent. Finally, we present numerical results to demonstrate the performance of the gradient algorithm from different aspects and reveal the low system complexity of deploying XL-RIS in massive MIMO systems with the help of VRs.
title Transmission Design for XL-RIS-Aided Massive MIMO System with Visibility Regions
topic Information Theory
url https://arxiv.org/abs/2407.07699