scholarly journals A Novel 3D Nonstationary Channel Model Based on the von Mises-Fisher Scattering Distribution

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yuming Bi ◽  
Jianhua Zhang ◽  
Ming Zeng ◽  
Mengmeng Liu ◽  
Xiaodong Xu
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Channel Model ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Azimuth Angle ◽  
Angle Of Arrival ◽  
Mean Values ◽  
Physical Channel ◽  
Von Mises

In the last decade, the nonstationary properties of channel models have attracted more and more attention for many scenarios, that is, vehicle-to-vehicle (V2V), mobile-to-mobile (M2M), and high-speed train (HST). However, little research has been done on the real-physical channel model. In this paper, we propose a generalized three-dimensional (3D) nonstationary channel model, in which the scatterers are assumed to be distributed around the transmitter (Tx) and receiver (Rx) on a two-sphere model. By employing the von Mises-Fisher distribution, the mean values of the azimuth angle of departure (AAoD) and elevation angle of departure (EAoD) and the azimuth angle of arrival (AAoA) and elevation angle of arrival (EAoA) are tracked by time-variant (TV) Brownian Markov (BM) motion paths, which ensure the nonstationarity of the proposed channel model. Moreover, the TV autocorrelation function (ACF) and Doppler power spectrum density (DPSD) of the proposed nonstationary channel model are calculated by using signal processing tools, for example, fast Fourier transform (FFT) and short-time Fourier transform (STFT). In addition, the simulation results show that the TV scatterer distribution results in a nonstationary nonisotropic channel model, and the proposed model can be employed to simulate the 3D nonstationary channel model.

Effect of position of the fiber transport channel on fiber motion in the high-speed rotor

2021 ◽  
pp. 004051752110018
Author(s):  
Rui Hua Yang ◽  
Chuang He ◽  
Bo Pan ◽  
Hongxiu Zhong ◽  
Cundong Xu
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Three Dimensional ◽  
Discrete Phase Model ◽  
Transport Channel ◽  
Rotor Spinning ◽  
Fiber Motion ◽  
Discrete Phase ◽  
Airflow Field ◽  
Fiber Transport

The task of the fiber transport channel (FTC) is to transport the fibers from the carding roller to the rotor. Its geometric position in the spinning machine has a strong influence on the characteristics of the airflow field and the trajectory of the fiber motion in both the rotor and the FTC. In this paper, a three-dimensional pumping rotor spinning channel model was established using ANSYS-ICEM-CFD software with three different positions of the FTC (positions a–c). Further, the simulations of air distribution were performed using Fluent software. In addition, the discrete phase model was used to fit the fiber motion trajectory in the rotor. The simulation results showed that among the three types of FTC, position b is the optimal condition. The gradients of airflow velocity in the channel at position b were greater than those of the other two positions, which is conducive to straightening of the fiber.

3D Profile Variety Measurement of Pectoral Fin in Fish Fast Start

2011 ◽  
Vol 83 ◽  
pp. 280-284
Author(s):  
Ming Jiang ◽  
Shu Zhang ◽  
Xiao Yuan He
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Kinetic Characteristic ◽  
Three Dimensional ◽  
Pectoral Fin ◽  
Fourier Transform Profilometry ◽  
Fast Start ◽  
Fringe Patterns ◽  
3D Information ◽  
3D Profile

Fast-starts are brief, sudden accelerations used by fish during predator-prey encounters. In this paper, a three-dimensional (3D) test and analysis method is critical to understand the function of the pectoral fin during maneuvers. An experiment method based on Fourier Transform Profilometry for 3D pectoral fin profile variety during fish maneuvers is proposed. This method was used in a carp fast-start during prey. Projecting the moiré fringes onto a carp pectoral fin it will produce the deformed fringe patterns contain 3D information. A high speed camera captures these time-sequence images. By Fourier transform, filter, inverse Fourier transform and unwrap these phase maps in 3D phase space, the complex pectoral fin profile variety were really reconstructed. The present study provides a new method to quantify the analysis of kinetic characteristic of the pectoral fin during maneuvers.

scholarly journals The Impact of Antenna Height on 3D-MIMO Channel: a Ray Launching Based Analysis

2017 ◽  
Author(s):  
Qi Hong ◽  
Jiliang Zhang ◽  
Hui Zheng ◽  
Hao Li ◽  
Haonan Hu ◽  
...  
Keyword(s):  
Channel Model ◽  
Elevation Angle ◽  
Base Station ◽  
Mimo Channel ◽  
Delay Spread ◽  
Three Dimension ◽  
Angle Of Arrival ◽  
3D Mimo ◽  
The Impact ◽  
Ray Launching

Three dimension (3D) Multi-input-multi-output (MIMO) scheme, which exploits another dimension of the spatial resource, is one of the enabling technologies for the next generation mobile communication. As the elevation angle in 3D-MIMO channel model might varies against the height of the base station transmit antenna, it has to be taken into account carefully. In this paper, the impact of antenna height on the channel characteristics of 3D MIMO channel is investigated by using the intelligent ray launching algorithm (IRLA). Three typical street scenarios, i.e., the straight street, the fork road and the cross road, are selected as benchmarks. On the basis of simulations, joint and marginal probability density functions (PDFs) of both the elevation angle of departure (EAoD) and the elevation angle of arrival (EAoA) are obtained. The elevation angle spread (AS) and the delay spread (DS) under various antenna heights are also discussed. Simulation results indicate that the PDFs of EAoD and EAoA vary characteristics under different street scenarios. Moreover, the minimum value of the DS can be achieved when the antenna height is half of the building height.

scholarly journals Optimisation of stress distribution in a highly loaded radial-axial gas microturbine using FEM

2020 ◽  
Vol 10 (1) ◽  
pp. 318-335 ◽  
Author(s):  
Paweł Zych ◽  
Grzegorz Żywica
Keyword(s):  
Stress Reduction ◽  
High Speed ◽  
Three Dimensional ◽  
Design Stage ◽  
Industrial Sectors ◽  
Reduction Methods ◽  
Scientists And Engineers ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Highly Loaded

AbstractThe article discusses the stress optimisation process of the highly loaded disc of a high-speed radial-axial microturbine. At the design stage, the strength optimisation is vitally important for these types of devices because they must withstand very high temperatures (600∘C in this case) and be capable of operating at high rotational speeds (96,000 rpm in this case). Calculations were made using a three dimensional FE numerical model. The optimisation process is strictly connected with the choice of materials — which in this case are Inconel 738 (nickel-cobalt super alloy) and silicon nitride. Several stress reduction methods were developed, which took into account the mass of the disc, the rotational speed of the rotor and the complex shape of the rear part of the disc. Numerical computations helped to choose the best optimisation method, which decreased maximum reduced von Mises stresses by about 45% (from 1,288 MPa to 705 MPa). The methods proposed in this article are universal and can be implemented in the design process of various high-speed radial-axial microturbines. This article could be of interest to scientists and engineers who deal with highly loaded microturbines, which are increasingly used in many industrial sectors.

Simulation and Analysis of Scattering Channel Models in Three-Dimensional High-Speed Mobile Environment

2016 ◽  
Vol 13 (10) ◽  
pp. 6947-6955
Author(s):  
Xin Chen ◽  
Yong Fang
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Three Dimensional ◽  
Mobile Terminal ◽  
Wireless Channel ◽  
Mobile Environment ◽  
Channel Models ◽  
Channel Characteristics ◽  
Channel Realization ◽  
Doppler Power

A three-dimensional (3D) statistic channel model based on scattering characteristics is proposed to describe accurately the wireless channel under the scenarios of high-speed train (HST). This paper derives scattering density distribution function and scattering coefficient to represent the channel impulse response (CIR) of HST communication system, and deduces closed expressions of Doppler power spectrum (DPS) of mobile terminal. Expressions are also provided for categorizing and quantizing the scattering characteristics of wireless channels. By analyzing the Doppler spread of HST and comparing the effects of scattering environment and mobile velocity on DPS, these works contribute to understand deeply the wireless scattering channel of HST. Numerical and simulation results demonstrate that the proposed scattering channel models can effectively depict the physical characteristics of HST wireless channel, which provide a reliable method to analyze and estimate channel parameters. Moreover, the channel realization in this paper is more straightforward and concise to study the scattering channel characteristics, which can also be utilized as a reference for experimental measurement campaigns and reducing the modeling errors of scattering channel model effectively.

scholarly journals Predicting Wireless MmWave Massive MIMO Channel Characteristics Using Machine Learning Algorithms

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lu Bai ◽  
Cheng-Xiang Wang ◽  
Jie Huang ◽  
Qian Xu ◽  
Yuqian Yang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Elevation Angle ◽  
Azimuth Angle ◽  
Machine Learning Algorithms ◽  
Statistical Characteristics ◽  
Mimo Channel ◽  
Angle Of Arrival ◽  
Millimetre Wave ◽  
Channel Characteristics ◽  
Mean Square Errors

This paper proposes a procedure of predicting channel characteristics based on a well-known machine learning (ML) algorithm and convolutional neural network (CNN), for three-dimensional (3D) millimetre wave (mmWave) massive multiple-input multiple-output (MIMO) indoor channels. The channel parameters, such as amplitude, delay, azimuth angle of departure (AAoD), elevation angle of departure (EAoD), azimuth angle of arrival (AAoA), and elevation angle of arrival (EAoA), are generated by a ray tracing software. After the data preprocessing, we can obtain the channel statistical characteristics (including expectations and spreads of the above-mentioned parameters) to train the CNN. The channel statistical characteristics of any subchannels in a specified indoor scenario can be predicted when the location information of the transmitter (Tx) antenna and receiver (Rx) antenna is input into the CNN trained by limited data. The predicted channel statistical characteristics can well fit the real channel statistical characteristics. The probability density functions (PDFs) of error square and root mean square errors (RMSEs) of channel statistical characteristics are also analyzed.

scholarly journals Nonisotropic Scattering Characteristic in an Alternant Tree-Blocked Viaduct Scenario on High-Speed Railway at 2.35 GHz

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Rongchen Sun ◽  
Cheng Tao ◽  
Liu Liu ◽  
Zhenhui Tan ◽  
Lingwen Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Radio Channel ◽  
Statistical Characteristics ◽  
Real Field ◽  
Line Of Sight ◽  
Angle Of Arrival ◽  
High Speed Railway ◽  
Scattering Characteristic ◽  
Nonisotropic Scattering

This paper presents the nonisotropic scattering characteristic of the mobile radio channel in an alternant tree-blocked viaduct scenario on high-speed railway (HSR) by real field measuring at 2.35 GHz. An angle of arrival (AOA) probability density function (PDF) is proposed for the nonuniform AOA at the mobile caused by stochastically distributed scatterers. Two Von Mises angular distributions with broad applicability are used to represent the line of sight (LOS) component and part of the scattering component in the AOA model. Based on such a PDF statistical characteristics of Ricean factor,κ, and AOA of the scattering component are modeled in LOS and obstructed line of sight (OLOS) cases, respectively. The results may give a meaningful and accurate channel model and could be utilized in HSR viaduct scenario evaluation.

scholarly journals Statistical Characteristics of Measured 3-Dimensional MIMO Channel for Outdoor-to-Indoor Scenario in China and New Zealand

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yawei Yu ◽  
Jianhua Zhang ◽  
Mansoor Shafi ◽  
Min Zhang ◽  
Jawad Mirza
Keyword(s):  
New Zealand ◽  
Channel Model ◽  
Elevation Angle ◽  
Statistical Characteristics ◽  
Mimo Channel ◽  
Delay Spread ◽  
Angle Of Arrival ◽  
Power Delay Profile ◽  
3 Dimensional ◽  
Rms Delay Spread

The 3-dimensional (3D) channel model gives a better understanding of statistical characteristics for practical channels than the 2-dimensional (2D) channel model, by taking the elevation domain into consideration. As different organizations and researchers have agreed to a standard 3D channel model, we attempt to measure the 3D channel and determine the parameters of the standard model. In this paper, we present the statistical propagation results of the 3D multiple-input and multiple-output (MIMO) channel measurement campaign performed in China and New Zealand (NZ). The measurements are done for an outdoor-to-indoor (O2I) urban scenario. The dense indoor terminals at different floors in a building form a typical 3D propagation environment. The key parameters of the channel are estimated from the measured channel impulse response (CIR) using the spatial-alternating generalized expectation-maximization (SAGE) algorithm. Till now there is abundant research performed on the azimuth domain; this paper mainly considers the statistical characteristics of the elevation domain. A statistical analysis of 3D MIMO channel results for both China and NZ measurements is presented for the following parameters: power delay profile (PDP), root mean square (rms), delay spread (DS), elevation angle-of-arrival (EAoA) distribution, elevation angle-of-departure (EAoD) distribution, elevation angular spread (AS), and cross-polarization discrimination (XPD).

Joint distribution of power and angle of arrival for three-dimensional channel model

2016 ◽  
Vol 10 (16) ◽  
pp. 2096-2105 ◽  
Author(s):  
Jiakang Xu ◽  
Yuanan Liu ◽  
Fang Liu ◽  
Weiming Wang
Keyword(s):  
Joint Distribution ◽  
Channel Model ◽  
Three Dimensional ◽  
Angle Of Arrival ◽  
Distribution Of Power
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