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IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA)

作者： Itzhak, Gal Cohen, Israel Technion Israel Inst Technol Andrew & Erna Viterbi Fac Elect & Comp Engn Haifa Israel

ISBN: (纸本)9798350323726

This paper presents a region-of-interest (ROI) oriented constant-beamwidth (CB) beamforming approach with rectangular arrays. We decompose a global rectangular beamformer into a Kronecker-product (KP) of two linear sub-beamformers: a uniform constant-beamwidth beamformer along the y-axis and a nonuniform robust superdirective (SD) beamformer along the x-axis whose topology is optimized for a broadband array directivity criterion. The KP decomposition allows a flexible tradeoff control between the CB threshold frequency and the array directivity by tuning the number of microphones along each axis. The topology optimization considers a continuous ROI and therefore does not require an accurate desired source direction in space. The proposed approach is compared to uniform rectangular arrays with uniform differential sub-beamformers along the x-axis. We show that the proposed method is advantageous regarding white noise gain and directivity factor measures, especially when the desired source direction differs from the estimated source direction.

关键词： Microphone arrays region-of-interest beamforming constant-beamwidth beamformer rectangular arrays

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Beam Depth Analysis for Large rectangular arrays

Beam Depth Analysis for Large Rectangular Arrays

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IEEE Conference on Global Communications (IEEE GLOBECOM) - Intelligent Communications for Shared Prosperity

作者： Kosasih, Alva Bjornson, Emil KTH Royal Inst Technol Div Commun Syst Stockholm Sweden

ISBN: (纸本)9798350310900

Most wireless communication systems operate in the far-field region of antennas and antenna arrays, where waves are planar and beams have infinite depth. When antenna arrays become electrically large, it is possible that the receiver is in the radiative near-field of the transmitter, and vice versa. Recent works have shown that near-field beamforming exhibits a finite depth, which enables a new depth-based spatial multiplexing paradigm. In this paper, we explore how the shape and size of a rectangular array determine the near-field beam behaviors. In particular, we investigate the 3 dB beam depth (BD), defined as the range of distances where the gain is greater than half of the peak gain. We derive analytical gain and BD expressions and prove how they depend on the aperture area and length. The largest BD is obtained for a square array while the smallest BD is obtained by a uniform linear array.

关键词： Beam depth active arrays Fresnel region finite-depth near-field beamforming rectangular arrays

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Finite Beam Depth Analysis for Large arrays

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2024年第8期23卷 10015-10029页

作者： Kosasih, Alva Bjornson, Emil KTH Royal Inst Technol Div Commun Syst Stockholm 16440 Sweden

Most wireless communication systems operate in the far-field region of antennas and antenna arrays, where waves are planar and beams have infinite depth. When antenna arrays become electrically large, it is possible that the receiver is in the radiative near-field of the transmitter, and vice versa. Recent works have shown that near-field beamforming exhibits a finite depth, which enables a new depth-based spatial multiplexing paradigm. In this paper, we explore how the shape and size of an array determine the near-field beam behaviors. In particular, we investigate the 3 dB beam depth (BD), defined as the range of distances where the gain is greater than half of the peak gain. We derive analytical gain and BD expressions and prove how they depend on the aperture area and length. For non-broadside transmissions, we find that the BD increases as the transmitter approaches the end-fire direction of the array. Furthermore, it is sufficient to characterize the BD for a broadside transmitter, as the beam pattern with a non-broadside transmitter can be approximated by that of a smaller/projected array with a broadside transmitter. Our analysis demonstrates that the BD can be ordered from smallest to largest as ULA, circular, and square arrays.

关键词： Array signal processing Transmitters Gain Antennas Behavioral sciences Phased arrays Wireless communication Beam depth beam width radiative near-field Fresnel region finite-depth beamforming rectangular arrays circular arrays

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Symmetry-Imposed rectangular Coprime and Nested arrays for Direction of Arrival Estimation With Multiple Signal Classification

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IEEE ACCESS 2019年 7卷 153217-153229页

作者： Adhikari, Kaushallya Drozdenko, Benjamin Louisiana Tech Univ Elect Engn Dept Ruston LA 71272 USA Louisiana Tech Univ Cyber Engn Dept Ruston LA 71272 USA

Linear sparse arrays (coprime and nested arrays) have been studied extensively as a means of performing direction of arrival (DoA) estimation while bypassing Nyquist sampling theorem. However, rectangular sparse arrays have few studies, most of which are based in lattice theory. Although the multiple signal classification (MUSIC) alogrithm can be applied to lattice theory-based sparse arrays, fewer DoAs can be estimated for these arrays than for a full array with the same aperture. One contribution of this paper is the formulation of symmetry-imposed rectangular coprime and nested array designs that have wider contiguous lags than lattice-based arrays. Also, existing algorithms for rectangular arrays employ the direct sample covariance matrix estimate, which has low accuracy. Another contribution of this paper is an alternate method for estimating the covariance matrix that ensures the matrix is block-Toeplitz. Using the proposed covariance matrix estimate, we integrate a MUSIC-based DoA estimation method that applies to both full arrays and sparse arrays. The results show that the covariance estimates produced by the proposed method have higher accuracy than the traditional sample covariance estimates. The results also demonstrate that symmetry-imposed sparse arrays have higher resolution than full rectangular arrays with the same number of sensors.

关键词： Covariance matrices Sensor arrays Direction-of-arrival estimation Multiple signal classification Estimation Apertures Coarray coprime arrays DoA estimation MUSIC nested arrays planar arrays rectangular arrays sparse arrays

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A NOVEL BAYESIAN APPROACH FOR THE TWO-DIMENSIONAL HARMONIC RETRIEVAL PROBLEM

A NOVEL BAYESIAN APPROACH FOR THE TWO-DIMENSIONAL HARMONIC R...

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Pote, Rohan R. Rao, Bhaskar D. Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

ISBN: (纸本)9781728176055

Sparse signal recovery algorithms like sparse Bayesian learning work well but the complexity quickly grows when tackling higher dimensional parametric dictionaries. In this work we propose a novel Bayesian strategy to address the two dimensional harmonic retrieval problem, through remodeling and reparameterization of the standard data model. This new model allows us to introduce a block sparsity structure in a manner that enables a natural pairing of the parameters in the two dimensions. The numerical simulations demonstrate that the inference algorithm developed (H-MSBL) does not suffer from source identifiability issues and is capable of estimating the harmonic components in challenging scenarios, while maintaining a low computational complexity.

关键词： sparse Bayesian learning multidimensional harmonic retrieval block sparsity rectangular arrays direction of arrival estimation

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Successive Standardization of rectangular arrays

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ALGORITHMS 2012年第1期5卷 98-112页

作者： Olshen, Richard A. Rajaratnam, Bala Stanford Univ Sch Med Dept Hlth Res & Policy Biostat HRP Redwood Bldg Stanford CA 94305 USA Stanford Univ Dept Elect Engn Stanford CA 94305 USA Stanford Univ Dept Stat Stanford CA 94305 USA Yang & Yamazaki Environm & Energy Bldg Dept Environm Earth Syst Sci Stanford CA 94305 USA Woods Inst Environm Stanford CA 94305 USA

In this note we illustrate and develop further with mathematics and examples, the work on successive standardization (or normalization) that is studied earlier by the same authors in [1] and [2]. Thus, we deal with successive iterations applied to rectangular arrays of numbers, where to avoid technical difficulties an array has at least three rows and at least three columns. Without loss, an iteration begins with operations on columns: first subtract the mean of each column;then divide by its standard deviation. The iteration continues with the same two operations done successively for rows. These four operations applied in sequence completes one iteration. One then iterates again, and again, and again, ... In [1] it was argued that if arrays are made up of real numbers, then the set for which convergence of these successive iterations fails has Lebesgue measure 0. The limiting array has row and column means 0, row and column standard deviations 1. A basic result on convergence given in [I] is true, though the argument in [1] is faulty. The result is stated in the form of a theorem here, and the argument for the theorem is correct. Moreover, many graphics given in [1] suggest that except for a set of entries of any array with Lebesgue measure 0, convergence is very rapid, eventually exponentially fast in the number of iterations. Because we learned this set of rules from Bradley Efron, we call it "Efron's algorithm". More importantly, the rapidity of convergence is illustrated by numerical examples.

关键词： rectangular arrays successive iterations exponentially fast convergence

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Analysis and Synthesis of a New Class of Low Side Lobe Planar arrays

Analysis and Synthesis of a New Class of Low Side Lobe Plana...

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作者： Khan, Iqtidar Ahmad Virginia Tech | University

Numerical techniques for designing planar arrays with low side lobe level often require memory intensive optimization algorithms and also initialization in the form of some known values of radiation pattern parameters beforehand - information that may not be available when designing arrays. A few analytical methods exist in the literature that can be used to design rectangular lattices of isotropic elements for desired half-power beamwidth and side lobe level, but the number of elements of the array often should be known before the design process. Some array designs based on analytical techniques may suffer from severe performance limitations, an example is the uniformly excited array which cannot produce side lobe levels below ̶13.3 dB. The goal of this study is to present an analytical technique for synthesis of planar arrays that, for specified radiation pattern requirements, not only provides quick solutions for the required number of elements and its distribution along the length and width of the array rectangular lattice, but also produces low side lobes without any limitation. A new class of non-uniformly excited equally spaced planar arrays is introduced and investigated in this study. The new array uses the patterns of uniformly excited linear arrays as its building blocks and has a separable element current distribution, hence making it mathematically convenient to analyze its radiation properties in terms of those of its constituent linear arrays. The proposed planar array does not suffer from the side lobe level limitation of uniformly excited planar arrays, and its synthesis, due to the analytical nature of description of its radiation properties, does not require iterative procedures that are inherent to numerical techniques. Radiation characteristics of the proposed planar array, including directivity, side lobe level, half-power beamwidths, far-field three dimensional radiation patterns, and element excitation currents, are examined and simulati

关键词： planar arrays array synthesis rectangular arrays low side lobe planar arrays. Thesis

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Two-Dimensional Input-Revolving Automata 5th

Two-Dimensional Input-Revolving Automata

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5th International Symposium on Computational Modeling of Objects Represented in Images. Fundamentals, Methods and Applications (CompIMAGE)

作者： Immanuel, S. James Thomas, D. G. Fernau, Henning Thamburaj, Robinson Nagar, Atulya K. Madras Christian Coll Dept Math Madras Tamil Nadu India Univ Trier Fachbereich Abt Informat 4 D-54286 Trier Germany Liverpool Hope Univ Dept Math & Comp Sci Liverpool Merseyside England

ISBN: (纸本)9783319546094;9783319546087

A new type of two-dimensional automaton for accepting two-dimensional languages, called as two-dimensional input-revolving automaton is introduced in this paper. It is an extension of input-revolving automaton for string languages. We bring out all the variants of this automaton which are based on the various types of column-revolving operations considered here. We compare the families of array languages accepted by the variants of these automata along with the well known families of Siromoney matrix languages. We discuss some of the closure properties of the new families of array languages and give an application in steganography.

关键词： Picture languages Extended finite automaton rectangular arrays Input-revolving

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Performance of a mmWave beamformed Phased array system for Indoor LOS Communication 4

Performance of a mmWave beamformed Phased array system for I...

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Conference on Infrared, Millimeter-Wave, and Terahertz Technologies IV

作者： Amjad, Kinnan Xu, Huaping Beihang Univ Aeronaut & Astron Sch Elect & Informat Engn Beijing 100191 Peoples R China

ISBN: (纸本)9781510604797;9781510604803

Millimeter waves (mmWaves) spectrum ranging from 30GHz to 300GHz is emerging as a potential solution to the bandwidth problem faced by the wireless communication now a days. The advancements in the antenna technology has enabled the fabrication of antenna arrays or phased array systems which when used with techniques like spatial multiplexing and beamforming has enabled the use of mmWaves for both indoor and outdoor communication systems by providing gain and selectivity. This has also opened the doors for its potential use in long range and cellular communications. The 60GHz band also know as the oxygen absorption band due to its higher attenuation and unlicensed operation is a good candidate for use in secure and confined communications. In this paper we have investigated the performance of a beamformed phased array system in the mmWave spectrum. The performance is measured for varying the source and noise location and compared for a Linear and rectangular array.

关键词： mmWaves LOS communication MVDR Beamforming Uniform Linear arrays rectangular arrays

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Two-dimensional jumping finite automata

Two-dimensional jumping finite automata

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作者： James Immanuel, S. Brno University of Technology

In this paper, we extend a newly introduced concept called the jumping nite automata for accepting string languages to two-dimensional jumping nite automata for accepting two-dimensional languages. We discuss some of the basic properties of these automata and compare the family of languages accepted by these automata with the family of Siromoney matrix languages and also recognizable picture languages (REC). We also discuss some of the closure properties of these automata along with some of their decidability properties.

关键词： picture languages jumping automata rectangular arrays

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