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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - A Multiscale, Multiphysics Approach to Vertical-cavity Surface-emitting Laser Simulation
摘要： For estimating the direction of arrival (DOA)s of non-stationary source signals such as speech and audio, a constrained optimization problem (COP) that exploits the spatial diversity provided by an array of sensors is formulated in terms of a noise-eliminated local th-order cumulant matrix. The COP solution provides a weight vector to the look direction such that it is constrained to the th-order source-signal subspace when the look direction is in alignment with the true DOA; otherwise, it is constrained to the th-order noise subspace. This weight vector is incorporated into the spatial spectrum to determine the degree of orthogonality between itself and either the th-order source-signal subspace when the number of sources is unknown, or the th-order noise subspace when the number of sources is known. For a uniform linear array (ULA) of sensors, the spatial spectrum for known number of sources can theoretically be shown to identify up to sources. Realizing the difficulty in identifying stationarity in the received sensor signals, the estimate of the noise-eliminated local th-order cumulant matrix is marginalized over various possible stationary segmentations, for a more robust DOA estimation. In this paper, we focus on the use of local second and fourth order cumulants ( , 2), and the proposed algorithms when outperformed the KR subspace-based algorithms and also the 4-MUSIC for globally non-stationary, non-Gaussian synthetic data and also for speech/audio in various adverse environments. We verified that the identifiability for is improved by two-folds compared to that for with an ULA.
关键词： DOA estimation,spatial spectrum.,non-stationary source signal,constrained optimization
更新于2025-09-16 10:30:52
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A Simple Resonant Switched Capacitor LED Driver Employed as a Fast Pulse-Based Transmitter for VLC Applications
摘要： With the rapid development of wireless communication networks, the need of massive Multiple-Input Multiple-Output (MIMO) to offer sufficient network capacity has become evident. As a part of array signal processing, direction-of-arrival (DoA) estimation is of vital importance to obtain directional information of sources and to enable the 3-D beamforming. In this paper, the performance of DoA estimation for massive MIMO systems is analyzed and compared using a low complexity algorithm. To be specific, 2-D unitary estimation of signal parameters via rotational invariance techniques (U-ESPRIT) algorithm is studied to jointly estimate elevation and azimuth information, and uniform rectangular array is selected to represent massive MIMO systems. The simulation results indicate that the U-ESPRIT algorithm works well for the massive MIMO systems. The performance has been evaluated with various types of antenna configuration and source numbers. Finally, the array resolution is adopted to analyze the performance of elevation and azimuth estimation and how to choose the appropriate antenna array configuration.
关键词： array resolution,DoA estimation,massive MIMO,unitary ESPRIT
更新于2025-09-16 10:30:52
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Single Snapshot Super-Resolution DOA Estimation for Arbitrary Array Geometries
摘要： We address the problem of search-free direction of arrival (DOA) estimation for sensor arrays of arbitrary geometry under the challenging conditions of a single snapshot and coherent sources. We extend a method of search-free super-resolution beamforming, originally applicable only for uniform linear arrays, to arrays of arbitrary geometry. The infinite dimensional primal atomic norm minimization problem in continuous angle domain is converted to a dual problem. By exploiting periodicity, the dual function is then represented with a trigonometric polynomial using a truncated Fourier series. A linear rule of thumb is derived for selecting the minimum number of Fourier coefficients required for accurate polynomial representation, based on the distance of the farthest sensor from a reference point. The dual problem is then expressed as a semidefinite program and solved efficiently. Finally, the search-free DOA estimates are obtained through polynomial rooting, and source amplitudes are recovered through least squares. Simulations using circular and random planar arrays show perfect DOA estimation in noise-free cases.
关键词： arbitrary array geometry,off-grid problem,coherent sources,limited snapshots,Super-resolution,sparse DOA estimation,compressive beamforming,atomic norm
更新于2025-09-09 09:28:46
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DoA and DoD Estimation and Hybrid Beamforming for Radar-Aided mmWave MIMO Vehicular Communication Systems
摘要： In millimeter wave (mmWave) communications, the feature of relatively large signal absorption and directional transmission render new challenges for wireless communications and signal processing. To further improve the performance of mmWave communications, a novel radar-aided mmWave communication (RAMC) approach is proposed, which can be used in vehicular communications. There are two parts in the proposed RAMC system, including the radar subsystem and the mmWave communication subsystem. In the radar subsystem, the bistatic co-prime multi-input and multi-output (MIMO) arrays are considered. With the radar antenna arrays, both the directions of departure (DoD) and the directions of arrival (DoA) are estimated. Additionally, the compressed sensing (CS)-based method is proposed to obtain the target positions. Using the estimated angle and position information, the channel estimation and feedback link of the mmWave communication subsystem can be eliminated. Moreover, a hybrid beamforming algorithm is proposed in the mmWave communication subsystem, which can overcome the shortage of the analog-only beamforming. Simulation results show that the better estimation performance can be achieved by the bistatic co-prime MIMO arrays than that by the traditional uniform linear arrays (ULA), and with the radar aided, the mmWave communication subsystem can reduce the beam search time, and the cell discovery time is improved significantly.
关键词： compressed sensing,millimeter wave,hybrid beamforming,DoA estimation,radar
更新于2025-09-09 09:28:46
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SPACE-TIME MATRIX METHOD FOR MIXED NEAR-FIELD AND FAR-FIELD SOURCES LOCALIZATION
摘要： Mixed near-?eld and far-?eld sources localization problem has received signi?cant attention recently in some practical applications, such as speaker localization using microphone arrays and guidance systems, etc. This paper presents a novel space-time matrix method to localize mixed near-?eld and far-?eld sources. Using the proposed method, both the direction-of-arrival (DOA) and range of a source can be estimated by the same eigen-pair of a de?ned space-time matrix. Therefore, the pairing of the estimated angles and ranges is automatically determined. Compared with the previous work, the presented method o?ers a number of advantages over other recently proposed algorithms. For example, it can avoid not only parameters matching problem but also aperture loss problem. It has lower computational complexity since the proposed method does not require the high-order statistics or any parameter search. Simulation results show the performance of the proposed algorithm.
关键词： DOA estimation,range estimation,space-time matrix method,mixed near-?eld and far-?eld sources localization
更新于2025-09-04 15:30:14
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Efficient Beamspace-Based Algorithm for 2-D DOA Estimation of Incoherently Distributed Sources in Massive MIMO Systems
摘要： In massive multiple-input multiple-output (MIMO) systems, accurate direction-of-arrival (DOA) estimation is critical for the transmitters to conduct downlink precoding. In this paper, we focus on the problem of two-dimensional DOA estimation of incoherently distributed sources in massive MIMO systems using uniform rectangular arrays (URAs). Firstly, with the generalized array manifold, we obtain the beamspace array manifold by performing beamspace transformation on the observed vector of the URA, and establish one beamspace shift invariance structure via appropriate beamforming matrix design and array manifold selection. Secondly, from the beamspace array manifold, we extract two array manifolds and derive the other beamspace shift invariance structure. Finally, the total least squares approach is used to estimate the nominal azimuth and elevation DOAs. With the DOA estimates, the corresponding angular spreads are given in closed-form solutions. Our approach avoids spectral search and reduces the dimensions in matrix operations, thus it is more computationally attractive than the existing techniques. Numerical results show that the proposed algorithm achieves performance comparable to that of the conventional estimators in massive MIMO systems.
关键词： incoherently distributed (ID) sources,beamspace shift invariance structure,massive multiple-input multiple-output (MIMO),2-D DOA estimation,beamspace transformation
更新于2025-09-04 15:30:14
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EFFICIENT LOCALIZATION ALGORITHM OF MIXED FAR-FIELD AND NEAR-FIELD SOURCES USING UNIFORM CIRCULAR ARRAY
摘要： An e?cient algorithm based on high-order cumulant is addressed for the scenarios where both far-?eld and near-?eld narrow-band signals may exist synchronously. The ?rst matrix built by four-order cumulant is utilized to estimate the two dimensional direction-of-arrivals (DOAs) using the orthogonal projection matrix of the signal subspace and the virtual steering matrix. Then, the second matrix built by four-order cumulant is decomposed to get the noise subspace using the eigen decomposition. Meanwhile, a virtual steering matrix is used to distinguish far-?eld signals (FFSs) from near-?eld signals (NFSs). And one-dimensional MUSIC algorithm is used to estimate the range of the NFSs. Compared to the TSMUSIC, the proposed algorithm can provide high resolution for the DOAs. In addition, there is higher accuracy for the DOA of NFS in the proposed algorithm than that in TSMUSIC and in TSMD. Simulation results are carried out to certify the performance of the proposed algorithm.
关键词： near-field signals,MUSIC algorithm,high-order cumulant,uniform circular array,far-field signals,DOA estimation
更新于2025-09-04 15:30:14