检索结果-内蒙古大学图书馆

Low-Rank Covariance Matrix Estimation for Factor Analysis in Anisotropic Noise: Application to array processing and Portfolio Selection

引用

ieee TRANSACTIONS ON signal processing 2023年 71卷 1699-1711页

作者： Stoica, Petre Babu, Prabhu Uppsala Univ Dept Informat Technol Div Syst & Control Uppsala S-75237 Sweden Indian Inst Technol Ctr Appl Res Elect Delhi 110016 India

Factor analysis (FA) or principal component analysis (PCA) models the covariance matrix of the observed data as R = SST + S, where SST is the low-rank covariance matrix corresponding to the factors (aka latent variables) and S is the diagonal matrix of the noise. When the noise is anisotropic (aka nonuniform in the signal processing literature and heteroscedastic in the statistical literature), the diagonal elements of S cannot be assumed to be identical and they must be estimated jointly with the elements of SST. The problem of estimating SST and S in the above covariance model is the central theme of the present article. After stating this problem in a more formal way, we review the main existing algorithms for solving it. We then go on to show that these algorithms have reliability issues (such as lack of convergence or convergence to infeasible solutions) and therefore they may not be the best possible choice for practical applications. Next we explain how to modify one of these algorithms to improve its convergence properties and we also introduce a new method that we call FAAN (Factor Analysis for Anisotropic Noise). FAAN is a coordinate descent algorithm that iteratively maximizes the normal likelihood function, which is easy to implement in a numerically efficient manner and has excellent convergence properties as illustrated by the numerical examples presented in the article. Out of the many possible applications of FAAN we focus on the following two: direction-of-arrival (DOA) estimation using array signal processing techniques and portfolio selection for financial asset management.

关键词： Factor model coordinate descent direction of arrival estimation portfolio selection

来源：评论

学校读者我要写书评

暂无评论

Outage Constrained Design for RIS-Assisted Integrated Sensing and Communication Systems

引用

ieee COMMUNICATIONS LETTERS 2025年第5期29卷 1037-1041页

作者： Huang, Xingxing Zhang, Guoping Xu, Hongbo Wang, Dong Li, Kunyu Wang, Ze Cent China Normal Univ Coll Phys Sci & Technol Wuhan 430079 Peoples R China

In practice, obtaining perfect channel state information (CSI) is challenging. This letter studies a reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) framework under imperfect CSI conditions. Specifically, in the statistical CSI error model, while ensuring the users' rate outage probability (OP) constraints and the minimum beampattern gain for radar targets, the total transmit power is minimized. To solve this non-convex problem, we rephrase the rate OP constraint through Bernstein inequality and suggest an alternating optimization algorithm. The numerical results validate the algorithm's effectiveness and reveal the influence of channel errors on system performance.

关键词： Reconfigurable intelligent surfaces Integrated sensing and communication array signal processing Vectors signal processing algorithms Optimization Radar antennas Radar Numerical models Training Integrated sensing and communication (ISAC) imperfect channel state information reconfigurable intelligent surface (RIS) beamforming design

来源：评论

学校读者我要写书评

暂无评论

array Calibration Using Neural Networks 9

Array Calibration Using Neural Networks

引用

9th ieee International workshop on Computational Advances in Multi-Sensor Adaptive processing (CAMSAP)

作者： Springer, Jannik Oispuu, Marc Koch, Wolfgang Knott, Peter Fraunhofer Inst Commun Informat Proc & Ergon FKIE Fraunhoferstr 20 D-53343 Wachtberg Germany Fraunhofer Inst High Frequency Phys & Radar Tech Fraunhoferstr 20 D-53343 Wachtberg Germany

ISBN: (纸本)9798350344523

This paper addresses the problem of calibration for antenna arrays. The performance of array signal processing techniques, like the super-resolution direction finding method MUltiple signal Classification, can significantly degrade if the assumed array model does not match the actual array response. In order to obtain an improved array model that accurately describes the actual array response, both parametric and nonparametric calibration methods have been proposed in the past. However, parametric methods often cannot fully capture the complex array response and non-parametric methods have an increased computational cost. This work proposes a new calibration method for array sensors based on neural networks. It achieves similar performance to non-parametric methods at moderate computational cost and offers a flexible applicability without the need to retain the neural network. The method is comprehensively studied in Monte-Carlo simulations and its performance is exemplarily evaluated for the multi-source direction finding problem.

关键词： array sensor antenna array calibration machine learning neural network Cramer-Rao lower bound

来源：评论

学校读者我要写书评

暂无评论

Uplink Multi-Beam Jointly processing With the Regional statistical CSI for Satellite IoT Networks

引用

ieee WIRELESS COMMUNICATIONS LETTERS 2025年第3期14卷 616-620页

作者： Xie, Xuxu Zhao, Shiqiu Li, Yuntao Wang, Yunfeng Ding, Xiaojin Zhang, Gengxin Nanjing Univ Posts & Telecommun Sch Commun & Informat Engn Nanjing 210003 Peoples R China Zaozhuang Univ Coll Informat Sci & Engn Zaozhuang 277100 Peoples R China

The situations (e.g., light control and Global Navigation Satellite System unavailable for terminals), as well as the long propagation delay and the high mobility in Low-Earth-Orbit (LEO) satellite Internet of Things networks, may result in that the perfect instantaneous channel state information (CSI) becomes hard to be acquired at satellites. To address this issue, we construct a unified regional statistical CSI (RsCSI) model for different scenarios (e.g., dense urban, urban, suburban and rural), without requiring the perfect positions of terminals and instantaneous CSI (iCSI). Our RsCSI model of a specific region is characterized by the channel power and the channel direction vector of the center point in this subregion, as well as the large-scale parameters. There parameters are fitted as a function of the varying elevation angle as the LEO satellite moves. Furthermore, our constructed model is also utilized for assisting the multi-beam jointly processing (MBJP), to optimize the user capacity. Performance evaluations show that our RsCSI aided MBJP obviously outperforms the conventional seven-color fequency reuse scheme in terms of a higher user capacity, whist the user capacity of RsCSI aided MBJP is a bit lower than that of the iCSI aided MBJP. The lifetime of the beamforming vectors generated by the RsCSI increases with a decreasing elevation angle, and the lifetime is more than 5 seconds when the elevation angle is 40 degrees.

关键词： Satellites Vectors Low earth orbit satellites array signal processing Internet of Things Uplink Satellite antennas Fitting Process control Phased arrays Lifetime multi-beam jointly processing regional statistical CSI satellite IoT

来源：评论

学校读者我要写书评

暂无评论

Proceedings - 2024 ieee workshop on signal processing Systems, SiPS 2024

Proceedings - 2024 IEEE Workshop on Signal Processing System...

引用

37th ieee International workshop on signal processing Systems, SiPS 2024

ISBN: (纸本)9798350373752

The proceedings contain 36 papers. The topics discussed include: evaluation of coarse-grained reconfigurable array for a dual mode OTFS-OFDM modulator;fast energy optimization of on-chip ECC memories;box decoding: a low-complexity algorithm for MIMO detection;HM-detect: a novel method for heart murmur detection and classification using machine learning and sound feature analysis;on the mismatch between the phase structure of all-pole-based synthetic vowels and natural vowels;QEEGNet: quantum machine learning for enhanced electroencephalography encoding;processing multi-layer perceptrons in-memory;hierarchical quantum control gates for functional MRI understanding;and noise identification for data-augmented physics-based state-space models.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Achievable Rate Optimization for Large Stacked Intelligent Metasurfaces Based on statistical CSI

引用

ieee WIRELESS COMMUNICATIONS LETTERS 2024年第9期13卷 2337-2341页

作者： Papazafeiropoulos, Anastasios Kourtessis, Pandelis Chatzinotas, Symeon Kaklamani, Dimitra I. Venieris, Iakovos S. Univ Hertfordshire Commun & Intelligent Syst Res Grp Hatfield AL10 9AB England Univ Luxembourg SnT L-2721 Luxembourg Luxembourg Natl Tech Univ Athens Zografou Microwave & Fiber Opt Lab Athens 15780 Greece Natl Tech Univ Athens Zografou Sch Elect & Comp Engn Intelligent Commun & Broadband Networks Lab Athens 15780 Greece

Stacked intelligent metasurface (SIM) is an emerging design that consists of multiple layers of metasurfaces. A SIM enables holographic multiple-input multiple-output (HMIMO) precoding in the wave domain, which results in the reduction of energy consumption and hardware cost. On the ground of multiuser beamforming, this letter focuses on the downlink achievable rate and its maximization. Contrary to previous works on multiuser SIM, we consider statistical channel state information (CSI) as opposed to instantaneous CSI to overcome challenges such as large overhead. Also, we examine the performance of large surfaces. We apply an alternating optimization (AO) algorithm regarding the phases of the SIM and the allocated transmit power. Simulations illustrate the performance of the considered large SIM-assisted design as well as the comparison between different CSI considerations.

关键词： Metasurfaces Optimization Downlink Vectors Reconfigurable intelligent surfaces array signal processing signal to noise ratio Reconfigurable intelligent surface (RIS) stacked intelligent metasurfaces (SIM) 6G networks

来源：评论

学校读者我要写书评

暂无评论

Advanced Methods for MLE of Toeplitz Structured Covariance Matrices With Applications to Radar Problems

引用

ieee TRANSACTIONS ON INFORMATION THEORY 2024年第12期70卷 9277-9292页

作者： Aubry, Augusto Babu, Prabhu De Maio, Antonio Rosamilia, Massimo Univ Napoli Federico II Dept Elect Engn & Informat Technol DIETI I-80125 Naples Italy Natl Interuniv Consortium Telecommun I-43124 Parma Italy IIT Delhi CARE New Delhi 110016 India

This work considers Maximum Likelihood Estimation (MLE) of a Toeplitz structured covariance matrix. In this regard, an equivalent reformulation of the MLE problem is introduced, and two iterative algorithms are proposed for the optimization of the equivalent statistical learning framework. Both strategies are based on the Majorization Minimization (MM) paradigm and hence enjoy nice properties such as monotonicity and ensured convergence to a stationary point of the equivalent MLE problem. The proposed framework is also extended to deal with MLE of other practically relevant covariance structures, namely, the banded Toeplitz, block Toeplitz, and Toeplitz-block-Toeplitz. Through numerical simulations, it is shown that the new methods provide excellent performance levels in terms of both mean square estimation error (which is very close to the benchmark Cramer-Rao Bound (CRB)) and signal-to-interference-plus-noise ratio, especially in comparison with state-of-the art strategies. Moreover, the estimation task is accomplished with a remarkable reduction in computational complexity compared with a standard approach relying on a Semidefinite Programming (SDP) solver.

关键词： Toeplitz covariance matrix maximum likelihood estimation banded Toeplitz block-Toeplitz Toeplitz-block-Toeplitz adaptive radar signal processing array processing spectral estimation

来源：评论

学校读者我要写书评

暂无评论

A PHYSICS-INFORMED NEURAL NETWORK-BASED APPROACH FOR THE SPATIAL UPSAMPLING OF SPHERICAL MICROPHONE arrayS 18

A PHYSICS-INFORMED NEURAL NETWORK-BASED APPROACH FOR THE SPA...

引用

18th International workshop on Acoustic signal Enhancement (IWAENC)

作者： Miotello, Federico Terminiello, Ferdinando Pezzoli, Mirco Bemardini, Alberto Antonacci, Fabio Sarti, Augusto Politecn Milan Dipartimento Elettron Informaz & Bioingn Via Ponzio 34-5 I-20133 Milan Italy

ISBN: (纸本)9798350361865;9798350361858

Spherical microphone arrays are convenient tools for capturing the spatial characteristics of a sound field. However, achieving superior spatial resolution requires arrays with numerous capsules, consequently leading to expensive devices. To address this issue, we present a method for spatially upsampling spherical microphone arrays with a limited number of capsules. Our approach exploits a physics-informed neural network with Rowdy activation functions, leveraging physical constraints to provide high-order microphone array signals, starting from low-order devices. Results show that, within its domain of application, our approach outperforms a state of the art method based on signal processing for spherical microphone arrays upsampling.

关键词： physics-informed neural network spherical microphone array space-time audio signal processing

来源：评论

学校读者我要写书评

暂无评论

Investigation of Randomly Populated Cylindrical, Spherical, and Cubical arrays for Application in Space, Aerial, and Underwater Collaborative Beamforming

引用

ieee ACCESS 2024年 12卷 171944-171971页

作者： Buchanan, Kristopher R. Manzano-Roth, Roanne Lin, Annie Loaiza, Gabriella Sills, Meghan Li, Jin Wheeland, Sara R. Chakrabarti, Sounak Rodriguez, Angelica R. Huff, Gregory H. Patefield, Mark Jones, Anthony NIWC Pacific San Diego CA 71000 USA Virginia Tech Dept Mech Engn Blacksburg VA 24061 USA CALTECH Jet Prop Lab Pasadena CA 91109 USA Penn State Univ Dept Elect & Comp Engn University Pk PA 16802 USA

This work investigates and analyzes collaborative beamforming for a Swarm-enabled distributed sensing project. It investigates the use of a three-dimensional, randomly populated, and uniformly-distributed array in three configurations: spherical, cylindrical, and cubical. These topologies uniquely act like a practical bound to contain the elements in swarm-type applications. In addition, these topologies provide mathematical simplicity toward understanding the fundamental research problem of both surface and underwater swarm-based UUV sensor networks, and their constraints to implementing a physical system in a volumetric setting. Therefore, statistical, ensemble, mean-valued average beampatterns scanned at the meridian elevation plane are analyzed in closed form using a large population of one million elements densely populated amongst geometrical bounds. This large density profile applies the law of large numbers in which numerical beampatterns converge to their expected (mean) patterns. Faithful agreement of the solution is shown to validate the distributed array pattern behavior. Finally, additional simulations are provided in this work using a cylindrical manifold that comprises ten, fifty, and one hundred isotropic radiators to determine the feasibility of a small element population.

关键词： Antenna arrays Sensor arrays array signal processing Radar antennas Collaboration Wireless sensor networks Topology Radar cross-sections Network topology Radio astronomy Ad hoc wireless network antenna array aperiodic array collaborative beamforming cooperative beamforming distributed beamforming random array sparse array thinned array wireless sensor network (WSN)

来源：评论

学校读者我要写书评

暂无评论

Stacked Intelligent Metasurface Enabled LEO Satellite Communications Relying on statistical CSI

引用

ieee WIRELESS COMMUNICATIONS LETTERS 2024年第5期13卷 1295-1299页

作者： Lin, Shining An, Jiancheng Gan, Lu Debbah, Merouane Yuen, Chau Univ Elect Sci & Technol China Sch Informat & Commun Engn Chengdu 611731 Sichuan Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Jurong West 639798 Singapore Yibin Inst UESTC Sch Informat & Commun Engn Yibin 644000 Peoples R China Khalifa Univ Sci & Technol KU 6G Res Ctr Abu Dhabi U Arab Emirates

Low earth orbit (LEO) satellite communication systems have gained increasing attention as a crucial supplement to terrestrial wireless networks due to their extensive coverage area. This letter presents a novel system design for LEO satellite systems by leveraging stacked intelligent metasurface (SIM) technology. Specifically, the lightweight and energy-efficient SIM is mounted on a satellite to achieve multiuser beamforming directly in the electromagnetic wave domain, which substantially reduces the processing delay and computational load of the satellite compared to the traditional digital beamforming scheme. To overcome the challenges of obtaining instantaneous channel state information (CSI) at the transmitter and maximize the system's performance, a joint power allocation and SIM phase shift optimization problem for maximizing the ergodic sum rate is formulated based on statistical CSI, and an alternating optimization (AO) algorithm is customized to solve it efficiently. Additionally, a user grouping method based on channel correlation and an antenna selection algorithm are proposed to further improve the system performance. Simulation results demonstrate the effectiveness of the proposed SIM-based LEO satellite system design and statistical CSI-based AO algorithm.

关键词： Metasurfaces Low earth orbit satellites Satellites Precoding Satellite broadcasting array signal processing Transmitting antennas Stacked intelligent metasurface (SIM) LEO satellite statistical CSI antenna selection user grouping

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：