Blind Beamforming for Coverage Enhancement with Intelligent Reflecting Surface

Fuente: arXiv
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Main Authors: Xu, Fan, Yao, Jiawei, Lai, Wenhai, Shen, Kaiming, Li, Xin, Chen, Xin, Luo, Zhi-Quan
Format: Preprint
Published: 2024
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author Xu, Fan
Yao, Jiawei
Lai, Wenhai
Shen, Kaiming
Li, Xin
Chen, Xin
Luo, Zhi-Quan
author_facet Xu, Fan
Yao, Jiawei
Lai, Wenhai
Shen, Kaiming
Li, Xin
Chen, Xin
Luo, Zhi-Quan
contents Conventional policy for configuring an intelligent reflecting surface (IRS) typically requires channel state information (CSI), thus incurring substantial overhead costs and facing incompatibility with the current network protocols. This paper proposes a blind beamforming strategy in the absence of CSI, aiming to boost the minimum signal-to-noise ratio (SNR) among all the receiver positions, namely the coverage enhancement. Although some existing works already consider the IRS-assisted coverage enhancement without CSI, they assume certain position-channel models through which the channels can be recovered from the geographic locations. In contrast, our approach solely relies on the received signal power data, not assuming any position-channel model. We examine the achievability and converse of the proposed blind beamforming method. If the IRS has $N$ reflective elements and there are $U$ receiver positions, then our method guarantees the minimum SNR of $Ω(N^2/U)$ -- which is fairly close to the upper bound $O(N+N^2\sqrt{\ln (NU)}/\sqrt[4]{U})$. Aside from the simulation results, we justify the practical use of blind beamforming in a field test at 2.6 GHz. According to the real-world experiment, the proposed blind beamforming method boosts the minimum SNR across seven random positions in a conference room by 18.22 dB, while the position-based method yields a boost of 12.08 dB.
format Preprint
id arxiv_https___arxiv_org_abs_2407_12648
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Blind Beamforming for Coverage Enhancement with Intelligent Reflecting Surface
Xu, Fan
Yao, Jiawei
Lai, Wenhai
Shen, Kaiming
Li, Xin
Chen, Xin
Luo, Zhi-Quan
Information Theory
Signal Processing
Conventional policy for configuring an intelligent reflecting surface (IRS) typically requires channel state information (CSI), thus incurring substantial overhead costs and facing incompatibility with the current network protocols. This paper proposes a blind beamforming strategy in the absence of CSI, aiming to boost the minimum signal-to-noise ratio (SNR) among all the receiver positions, namely the coverage enhancement. Although some existing works already consider the IRS-assisted coverage enhancement without CSI, they assume certain position-channel models through which the channels can be recovered from the geographic locations. In contrast, our approach solely relies on the received signal power data, not assuming any position-channel model. We examine the achievability and converse of the proposed blind beamforming method. If the IRS has $N$ reflective elements and there are $U$ receiver positions, then our method guarantees the minimum SNR of $Ω(N^2/U)$ -- which is fairly close to the upper bound $O(N+N^2\sqrt{\ln (NU)}/\sqrt[4]{U})$. Aside from the simulation results, we justify the practical use of blind beamforming in a field test at 2.6 GHz. According to the real-world experiment, the proposed blind beamforming method boosts the minimum SNR across seven random positions in a conference room by 18.22 dB, while the position-based method yields a boost of 12.08 dB.
title Blind Beamforming for Coverage Enhancement with Intelligent Reflecting Surface
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2407.12648