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IEEE Global Communications Conference (GLOBECOM)

作者： Liu, Bin Guevara, Andrea P. Van der Perre, Liesbet Pollin, Sofie Katholieke Univ Leuven Dept Elect Engn Leuven Belgium

ISBN: (纸本)9781728181042

In this paper, we experimentally analyze the spatial distribution of nonlinear distortion in massive MIMO systems with various array topologies and user locations. With an indoor channel measurement, we reveal the spatial distortion distribution of the in-band (IB) and out-of-band (OOB) power leakage in a real-life scenario. We further investigate the power leakage under different antenna array topologies: including uniform linear array (ULA), uniform rectangular array (URA), distributed linear subarrays (DIS). The impact of user location on the per antenna distortion is also visualized. The results indicate that the DIS array configuration achieves the lowest in-band and out-of-band power leakage, which renders the distributed array a potential to reduce the linearity requirement of PAs when scaling up a practical massive MIMO system.

关键词： Massive MIMO distributed array nonlinear PAs power leakage

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Joint Measurement of Target Angle and Angular Velocity Using Interferometric Radar with FM Waveforms

Joint Measurement of Target Angle and Angular Velocity Using...

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IEEE Radar Conference (RadarConf)

作者： Merlo, Jason Nanzer, Jeffrey A. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48824 USA

ISBN: (纸本)9781728189420

An architecture for a direct-downconversion complex correlation interferometric radar capable of the direct, joint measurement of angle and angular velocity of a point-target is presented. Due to the simplicity of the system, this technique can be implemented on existing radars with distributed receivers and a transmitter capable of frequency modulation. Derivations for the interferometric measurement of angle and angular velocity and guidelines for the design of such a system are presented. Simulations are provided for the proposed system with varying pulse-width, antenna baseline, and pulse center frequency. The results for all simulations show a low root-mean-square error which demonstrates the feasibility of the proposed system.

关键词： Correlation Interferometry Angle Estimation Angular Velocity Estimation distributed array distributed Radar

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APAT: An Access Pattern Analysis Tool For distributed arrays 15

APAT: An Access Pattern Analysis Tool For Distributed Arrays

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15th ACM International Conference on Computing Frontiers

作者： Kayraklioglu, Engin El-Ghazawi, Tarek George Washington Univ Washington DC 20052 USA

ISBN: (纸本)9781450357616

distributed arrays reduce programming effort through implicit communication. However, relying solely on this abstraction causes fine-grained communication and performance overhead. A variety of optimization techniques can be used to mitigate such overheads. However, these techniques require a thorough understanding of how distributed arrays are accessed which can be very challenging in realistic use cases. We present Access Pattern Analysis Tool (APAT) for distributed arrays. APAT is a framework that can be integrated into language software stack to efficiently collect access logs and analyze them. We show that APAT can help discover optimization opportunities that can lead to up to 35% improvement.

关键词： profiling distributed array data locality optimization

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Robust Automotive Satellite Navigation Achieved with distributed Groups of Sub-arrays 41

Robust Automotive Satellite Navigation Achieved with Distrib...

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41st Annual Symposium of the Antenna-Measurement-Techniques-Association (AMTA)

作者： Hasnain, Syed N. Stephan, Ralf Brachvogel, Marius Meurer, Michael Hein, Matthias A. Tech Univ Ilmenau RF & Microwave Res Grp Thuringian Ctr Innovat Mobil Ilmenau Germany Rhein Westfal TH Aachen Chair Nav Aachen Germany German Aerosp Ctr DLR Inst Commun & Nav Wessling Germany

ISBN: (纸本)9781728145259

Ambiguous direction-of-arrival estimation is a key problem for uniformly distributed antenna arrays with inter-element spacing exceeding half of the carrier wavelength. The primary reason behind such ambiguity are the grating lobes generated in the radiation patterns due to insufficient spatial sampling. An L-shaped orthogonal arrangement of radiating elements in distributed sub-arrays is an approach that removes grating lobes and consequent ambiguity to a great extent. The reduction of footprint area by distributing the elements across a car also makes it a suitable approach for conformal integration into automotive exterior parts. In order to realize the feasibility of its application in passenger cars, we investigate and evaluate this concept through measurements and digital array signal processing. This paper presents a comparison of L-shaped antenna element arrangements for different spacings between two sub-arrays, as well as a verification of the concept when mounted on a passenger car. For each scenario, the radiation patterns are analyzed and the robustness of the system against a static interferer is verified.

关键词： distributed array automotive antenna satellite navigation direction-of-arrival interference mitigation

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Study on Coherent Synthesis of Broadband Time Inversion Signals

Study on Coherent Synthesis of Broadband Time Inversion Sign...

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IEEE International Conference on Automation, Electronics and Electrical Engineering (AUTEEE)

作者： Tian, Siyuan Huang, Jianchong Chen, Qiuju Natl Univ Def Technol Coll Elect Countermeasures Hefei Anhui Peoples R China

ISBN: (纸本)9781538678619

First, a broadband time inversion signal coherent synthesis model is established based on distributed array. On this basis, the change of time domain, frequency domain and auto-correlation characteristics of broadband signal after time inversion is studied. Under the condition of random phase modulation and random amplitude modulation for broadband signal, the variation of the coherent synthetic superposition gain affected by the Time Position Difference of the signal is also studied. The focusing characteristics of broadband modulated signal under the condition of time inversion are preliminarily explored. The conclusion can provide a theoretical basis for the application of time inversion in engineering.

关键词： distributed array Time inversion wave Broadband signal Coherent synthesis

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Geometric Calibration of distributed Microphone arrays Based on Cross-Correlation Function 1

Geometric Calibration of Distributed Microphone Arrays Based...

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1st Annual International Conference on Sensor Networks and Signal Processing (SNSP)

作者： Lu, Sheng Tao, Jianbo Wang, Wennai Nanjing Univ Posts & Telecommun Sch Commun & Informat Engn Nanjing 210003 Peoples R China

ISBN: (纸本)9781538674130

In this paper, we provide a solution to achieve the robustness of geometric calibration of distributed microphone arrays, under the condition that each microphone array has a non-ideal knowledge of the position of the microphones. We consider two microphone arrays located in arbitrary positions and propose a robust algorithm for sound source mapping based on cross-correlation function by placing a sound source in N different positions in the visual range of the two microphone arrays. An estimation is provided also on the rotation matrix R and translation vector t, which can represent the position and direction between two microphone arrays, using the techniques of Computer Vision. Experimental results demonstrate that the calibration algorithm based on cross-correlation function still performs well even in presence of a high microphone position error.

关键词： microphone array geometric calibration distributed array cross-correlation

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Combining a distributed flow manifold and 3D woven metallic lattices to enhance fluidic and thermal properties for heat transfer applications

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2017年第PartB期108卷 2169-2180页

作者： Zhao, Longyu Ryan, Stephen M. Lin, Sen Xue, Ju Ha, Seunghyun Igusa, Takeru Sharp, Keith W. Guest, James K. Hemker, Kevin J. Weihs, Timothy P. Johns Hopkins Univ Dept Mat Sci & Engn 3400 N Charles StMaryland Hall 205 Baltimore MD 21218 USA Johns Hopkins Univ Dept Civil Engn 3400 N Charles St Baltimore MD 21218 USA Korea Maritime & Ocean Univ Dept Ocean Engn 727 Taejong Ro Busan 606791 South Korea SAERTEX USA LLC Huntersville NC 28078 USA Johns Hopkins Univ Dept Mech Engn 3400 N Charles St Baltimore MD 21218 USA

The fluidic and heat transfer capabilities of 3D woven lattice materials were reported recently under axial and bifurcated flow patterns, but three critical performance indices - pressure drop, average surface temperature and temperature uniformity - could not be optimized simultaneously using these flow patterns. Here we combine the 3D weaves with manifolds to create a novel 3D flow pattern that enhances temperature uniformity, while also maintaining low pressure drops and surface temperatures. These three properties were characterized at room temperature for a range of flow rates using water as the working fluid. Three different weaves thicknesses were investigated: 12.7 mm, 6.4 mm, and 3.2 mm, with manifold thicknesses of 12.7 mm, 19.0 mm, and 22.2 mm, respectively, to provide a constant, combined weave manifold thickness of 25.4 mm. The properties of this new weave/manifold system are compared to those obtained using just the manifold (with no weave) and just the weave (with no manifold). Comparisons show that the addition of the weave lowers the average substrate temperature and temperature variations significantly, although pressure drop is increased. They also show that the addition of the manifold improves temperature uniformity significantly, and also lowers the average substrate temperature and the pressure drop. No specific ratio of weave to manifold thickness was found to be superior in all of the performance indices. The thermal performances are then evaluated at different pumping powers: the weave/manifold system and its distributed array flow pattern prevail. Finite element simulations were performed on a reduced and simplified model to explain the observed experimental trends, and manifold opening patterns were manipulated to demonstrate further potential property enhancements. The multiple benefits of this manifold system can be extended to common heat exchanger media beyond weaves. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： 3D woven lattice materials Flow manifold distributed array Topology optimization Heat exchanger

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Multi-Frequency distributed arrays for Underdetermined Direction-of-Arrival Estimation

Multi-Frequency Distributed Arrays for Underdetermined Direc...

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CIE International Conference on Radar (RADAR)

作者： Wang, Yi Chen, Baixiao Yang, Minglei Ma, Yan Xidian Univ Natl Lab Radar Signal Proc Xian Shaanxi Peoples R China

ISBN: (纸本)9781509048281

distributed array can obtain a higher aperture than conventional uniform linear array, thus obtain high direction of arrival (DOA) estimation accuracy. However, the degree of freedom of the difference co-array of the distributed array has not been fully used. In this paper, the multi frequency is used to complete the missing elements of the co-array of the distributed array. The wideband sensor output is first transformed to the desired additional frequency via the discrete Fourier transform, and the holes of the covariance vector at the center frequency can be completed using the covariance matrix at the additional frequency. Then the high-resolution DOA estimation method SSMUSIC can be employed to the whole co-array. The proposed method has higher estimation accuracy than the single frequency distributed array in the underdetermined case. Simulation results show the effectiveness of the proposed method.

关键词： distributed array direction of arrival multi frequency

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distributed Scheme Versus MOFPA array on the Power Scaling of a Monolithic Fiber Laser

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IEEE JOURNAL OF QUANTUM ELECTRONICS 2014年第8期50卷 698-708页

作者： Ilchi-Ghazaani, Maryam Parvin, Parviz Amirkabir Univ Technol Dept Phys Photon Engn Grp Tehran 158754413 Iran

A couple of amplifying arrays for the power scaling of the fiber lasers under diverse pumping modes are studied. The multifiber series distributed side-pumping arrangement and the cascade amplifier chains in the form of the end-pumped master oscillator fiber power amplifier (MOFPA) scheme are investigated accordingly. Those are numerically modeled based on the propagation rate equations associated with stimulated Brillouin scattering (SBS) as well as the consideration of coupling and splicing losses for large mode area fibers. The continuous wave double-clad Yb:silica fiber laser amplifier is analyzed in various amplifying stages for several cavity lengths at forward pumping regime. Despite the distributed mode exhibits a desirable beam quality, however, it suffers a low SBS threshold. On the other hand, high output power is achieved in the MOFPA configuration far from the onset of SBS.

关键词： distributed array fiber laser - amplifier master oscillator fiber power amplifier numerical analysis with considering SBS side- and end-pumping

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Effects of local oscillator errors on digital beamforming

Effects of local oscillator errors on digital beamforming

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作者： Marcos Chi Lim Siu US Naval Postgraduate School

学位级别：硕士

Digital phased array antennas are sensitive to phase error among elements because it affects the coherence necessary to create the array factor. There are many sources for phase errors: local oscillators and clocks, quadrature modulators and demodulators, non-linear components, and so forth. Additionally, phased arrays are sensitive to element mislocation, which introduces another source of phase error. In this research, three types of phase errors were studied: phase noise, gain unbalance in quadrature modulators and demodulators, and element mislocation. Modifications to the traditional array pattern expression were proposed to account for these errors, and equations were programmed in MATLAB to perform parametric simulations to generate information regarding gain loss, beam pointing error, pattern distortions, and degradation in sidelobe levels. The objective is to aid array designers in setting acceptable tolerance limits for these types of errors.

关键词： radar distributed array phased array phase synchronization digital array digital beamforming (dbf) wireless sensor network transmit/receive (t/r) module local oscillator phase noise

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