Wideband Channel Estimation for IRS-Aided Systems in the Face of Beam Squint

Ma, Siqi; Shen, Wenqian; An, Jianping; Hanzo, Lajos

doi:10.1109/twc.2021.3072694

Cited by 48 publications

(34 citation statements)

References 36 publications

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“…Correspondingly, different subcarriers may point towards different directions for transmitting and cause dispersion problems. It is proved in [156] that the cross-correlation function between the spatial steering vector and the cascaded channel has two peaks in the angle domain, that is, the frequencydependent actual angle and the frequency-independent error angle. The existence of the error angle affects estimation performance severely, and a two-stage orthogonal matching pursuit (TS-OMP) algorithm is designed accordingly.…”

Section: Channel Estimation In Ris-empowered Systemsmentioning

confidence: 99%

Reconfigurable Intelligent Surfaces for Wireless Communications: Overview of Hardware Designs, Channel Models, and Estimation Techniques

Jian¹,

Alexandropoulos²,

Başar³

et al. 2022

Preprint

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The demanding objectives for the future sixth generation (6G) of wireless communication networks have spurred recent research efforts on novel materials and radio-frequency front-end architectures for wireless connectivity, as well as revolutionary communication and computing paradigms. Among the pioneering candidate technologies for 6G belong the reconfigurable intelligent surfaces (RISs), which are artificial planar structures with integrated electronic circuits that can be programmed to manipulate the incoming electromagnetic field in a wide variety of functionalities. Incorporating RISs in wireless networks has been recently advocated as a revolutionary means to transform any wireless signal propagation environment to a dynamically programmable one, intended for various networking objectives, such as coverage extension and capacity boosting, spatiotemporal focusing with benefits in energy efficiency and secrecy, and low electromagnetic field exposure.Motivated by the recent increasing interests in the field of RISs and the consequent pioneering concept of the RIS-enabled smart wireless environments, in this paper, we overview and taxonomize the latest advances in RIS hardware architectures as well as the most recent developments in the modeling of RIS unit elements and RIS-empowered wireless signal propagation. We also present a thorough overview of the channel estimation approaches for RIS-empowered communications systems, which constitute a prerequisite step for the optimized incorporation of RISs in future wireless networks. Finally, we discuss the relevance of the RIS technology in the latest wireless communication standards, and highlight the current and future standardization activities for the RIS technology and the consequent RIS-empowered wireless networking approaches.

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Section: Channel Estimation In Ris-empowered Systemsmentioning

confidence: 99%

Reconfigurable Intelligent Surfaces for Wireless Communications: Overview of Hardware Designs, Channel Models, and Estimation Techniques

Jian¹,

Alexandropoulos²,

Başar³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Then, the FFT method is used to estimate the DOA of targets. • OMP method [39]- [41]: OMP method is a grid-based method for sparse reconstruction, where the interference from the AP is removed first. The OMP method has lower computational complexity in the scenario with fewer grids but higher with more grids, where a matrix inverse determines the complexity at the iterative step.…”

Section: Parameter Valuementioning

confidence: 99%

A RIS-Based Passive DOA Estimation Method for Integrated Sensing and Communication System

Chen¹,

Chen²,

Wang³

2022

Preprint

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Integrated sensing and communication (ISAC) system has received growing attention, especially in the context of B5G/6G development. Combining the reconfigurable intelligent surface (RIS) with wireless communication process, a novel passive sensing technique is formulated in this paper to estimate the direction of arrival (DOA) of the targets, where the control matrix of the RIS is used to to realize the multiple measurements with only one full-functional receiving channel. Unlike the existing methods, the interference signals introduced by wireless communication are also considered. To improve the DOA estimation, a novel atomic norm-based method is proposed to remove the interference signals by the sparse reconstruction. The DOA is estimated after the interference removal by a novel Hankel-based multiple signal classification (MUSIC) method. Then, an optimization method is also developed for the measurement matrix to reduce the power interference signals and keep the measurement matrix's randomness, which guarantees the performance of the sparse reconstruction. Finally, we derive the theoretical Cramér-Rao lower bound (CRLB) for the proposed system on the DOA estimation. Simulation results show that the proposed method outperforms the existing methods in the DOA estimation and shows the corresponding CRLB with different distributions of the sensing node. The code about the proposed method is available online https://github.com/chenpengseu/ PassiveDOA-ISAC-RIS.git.

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“…The authors in [48] consider both the channel's frequency selectivity and the effect of beam squint to develop a twin-stage orthogonal matching pursuit (TS-OMP) CSI estimation algorithm in a single-user SISO wideband OFDM system by considering NLOS between both ends, i.e., only the cascaded BS-IRS-user channel is estimated in the downlink. The authors demonstrate that the mutual correlation function between the spatial steering vectors and the cascaded channel presents two peaks, which leads to a pair of estimated angles for a single propagation path due to the beam squint effect.…”

Section: Wideband Systems Under Beam Squintmentioning

confidence: 99%

“…Moreover, the large channel bandwidth leads to the beam squint effect, which in turn leads to more constrained designs. The work in [48] considers a wideband IRS-aided communication system under the beam squint effect. However, the work focuses on the channel acquisition problem and not on the IRS design for these systems.…”

Section: Wideband Systemsmentioning

confidence: 99%

Intelligent Reflective Surfaces for Wireless Networks: An Overview of Applications, Approached Issues, and Open Problems

et al. 2021

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An intelligent reflective surface (IRS) is a novel and revolutionizing communication technology destined to enable the control of the radio environment. An IRS is a real-time controllable reflectarray with a massive number of low-cost passive elements which introduce a phase shift to the incoming signals from the sources before the propagation towards the destination. This technology introduces the notion of a smart propagation environment with the aim of improving the system performance. In this paper, we provide a comprehensive literature overview on IRS technology, including its basic concepts and reconfiguration, as well as its design aspects and applications for wireless communication systems. We also study the performance metrics and the setups considered in recent publications related to IRS and provide suggestions of future research lines based on still unexplored use cases in the state-of-the-art.

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Wideband Channel Estimation for IRS-Aided Systems in the Face of Beam Squint

Cited by 48 publications

References 36 publications

Reconfigurable Intelligent Surfaces for Wireless Communications: Overview of Hardware Designs, Channel Models, and Estimation Techniques

Reconfigurable Intelligent Surfaces for Wireless Communications: Overview of Hardware Designs, Channel Models, and Estimation Techniques

A RIS-Based Passive DOA Estimation Method for Integrated Sensing and Communication System

Intelligent Reflective Surfaces for Wireless Networks: An Overview of Applications, Approached Issues, and Open Problems

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