scholarly journals A Three-Dimensional Geometry-Based Statistical Model of2×2Dual-Polarized MIMO Mobile-to-Mobile Wideband Channels

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Jun Chen ◽  
Thomas G. Pratt
Keyword(s):  
Fading Channels ◽  
Channel Model ◽  
Reference Model ◽  
Three Dimensional ◽  
Multipath Fading ◽  
Model Parameters ◽  
Wide Sense ◽  
Scattering Loss ◽  
Time Frequency ◽  
Concentric Spheres

A three-dimensional (3D) model for wide-band dual-polarized (DP) multiple-input-multiple-output (MIMO) mobile-to-mobile (M2M) channels is proposed. Using geometrical scattering based on concentric spheres at the transmitter (Tx) and at the receiver (Rx), a 3D parametric reference model for2×2M2M DP multipath fading channels is developed. The channel model assumes the use of colocated half-wavelength dipole antennas for vertical and horizontal polarizations at both transmit and receive stations. Model parameters include the velocities of the Tx and Rx nodes, the distance between the nodes, the 3D antenna pattern gains, the azimuth and elevation angles of arrival and departure, the geometrical distribution of the scatterers, the Rician K-factors defining the fading envelope distributions, the maximum Doppler frequency, the scattering loss factors, the cross-polar power discrimination ratio (XPD), and the copolarization power ratio (CPR). Using the proposed model, expressions for joint time-frequency correlation functions (TFCFs) are derived which are used to investigate system behavior over different wide sense stationary uncorrelated scattering (WSSUS) channel realizations. The numerical results illustrate the sensitivities of the TFCF to simultaneous time and frequency offsets for the2×2DP-MIMO architectures.

scholarly journals Modeling of Non-WSSUS Double-Rayleigh Fading Channels for Vehicular Communications

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Carlos A. Gutiérrez ◽  
J. J. Jaime-Rodríguez ◽  
J. M. Luna-Rivera ◽  
Daniel U. Campos-Delgado ◽  
Javier Vázquez Castillo
Keyword(s):  
Fading Channels ◽  
Communication Systems ◽  
Rayleigh Fading ◽  
Channel Model ◽  
Closed Form Solution ◽  
Multipath Fading ◽  
Rayleigh Distribution ◽  
Rayleigh Fading Channels ◽  
Small Scale ◽  
Time Frequency

This paper deals with the modeling of nonstationary time-frequency (TF) dispersive multipath fading channels for vehicle-to-vehicle (V2V) communication systems. As a main contribution, the paper presents a novel geometry-based statistical channel model that facilitates the analysis of the nonstationarities of V2V fading channels arising at a small-scale level due to the time-varying nature of the propagation delays. This new geometrical channel model has been formulated following the principles of plane wave propagation (PWP) and assuming that the transmitted signal reaches the receiver antenna through double interactions with multiple interfering objects (IOs) randomly located in the propagation area. As a consequence of such interactions, the first-order statistics of the channel model’s envelope are shown to follow a worse-than-Rayleigh distribution; specifically, they follow a double-Rayleigh distribution. General expressions are derived for the envelope and phase distributions, four-dimensional (4D) TF correlation function (TF-CF), and TF-dependent delay and Doppler profiles of the proposed channel model. Such expressions are valid regardless of the underlying geometry of the propagation area. Furthermore, a closed-form solution of the 4D TF-CF is presented for the particular case of the geometrical two-ring scattering model. The obtained results provide new theoretical insights into the correlation and spectral properties of small-scale nonstationary V2V double-Rayleigh fading channels.

scholarly journals Joint Delay Doppler Probability Density Functions for Air-to-Air Channels

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Michael Walter ◽  
Dmitriy Shutin ◽  
Uwe-Carsten Fiebig
Keyword(s):  
Probability Density ◽  
Channel Model ◽  
Three Dimensional ◽  
Doppler Frequency ◽  
Probability Density Functions ◽  
Density Functions ◽  
Wide Sense ◽  
Channel Measurements ◽  
Vector Calculus ◽  
Air Channels

Recent channel measurements indicate that the wide sense stationary uncorrelated scattering assumption is not valid for air-to-air channels. Therefore, purely stochastic channel models cannot be used. In order to cope with the nonstationarity a geometric component is included. In this paper we extend a previously presented two-dimensional geometric stochastic model originally developed for vehicle-to-vehicle communication to a three-dimensional air-to-air channel model. Novel joint time-variant delay Doppler probability density functions are presented. The probability density functions are derived by using vector calculus and parametric equations of the delay ellipses. This allows us to obtain closed form mathematical expressions for the probability density functions, which can then be calculated for any delay and Doppler frequency at arbitrary times numerically.

scholarly journals Statistical Characterization of Novel 3D Cluster-Based MIMO Vehicle-to-Vehicle Models for Urban Street Scattering Environments

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Xin Chen ◽  
Yong Fang ◽  
Yanzan Sun ◽  
Yuntian Pan ◽  
Weidong Xiang
Keyword(s):  
Channel Model ◽  
Reference Model ◽  
Three Dimensional ◽  
Measurement Data ◽  
Time Correlation ◽  
Time Correlation Function ◽  
Statistical Characterization ◽  
Urban Street ◽  
Vehicle To Vehicle ◽  
V2v Communications

We develop a novel three-dimensional (3D) cluster-based channel model for vehicle-to-vehicle (V2V) communications under the scenarios of urban street scattering environments. The proposed model combines the flexibility of geometrical channel models with the existing state-of-the-art 3D V2V models. To provide an accurate representation of specific locations and realistic V2V fading environments in a computationally manageable fashion, all clusters are divided into three groups of use cases including “ahead,” “between,” and “behind” clusters according to the relative locations of clusters. Using the proposed V2V model, we first derive the closed-form expressions of the channel impulse response (CIR), including the line-of-sight (LoS) components and cluster components. Subsequently, for three categories of clusters, the corresponding statistical properties of the reference model are studied. We additionally derive the expressions of the 3D space-time correlation function (STCF), the autocorrelation function (ACF), and 2D STCF. Finally, comparisons with on-road measurement data and numerical experiments demonstrate the validity and effectiveness of the proposed 3D cluster-based V2V model.

Three-Dimensional Face Shape by Local Fitting to a Single Reference Model

2014 ◽  
Vol 4 (1) ◽  
pp. 17-29
Author(s):  
Rubén García-Zurdo
Keyword(s):  
Reference Model ◽  
Three Dimensional ◽  
Neuronal Model ◽  
Reconstruction Error ◽  
Input Image ◽  
Weighted Averaging ◽  
Model Parameters ◽  
Simple Method ◽  
Illumination Estimation ◽  
Average Reference

The authors present a simple method to estimate the three-dimensional shape of a face from an input image using a single reference model, based on least squares between the output of the linear-nonlinear (LN) neuronal model applied to blocks from an intensity image and blocks from a depth reference model. The authors present the results obtained by varying the LN model parameters and estimate their best values, which provide an acceptable reconstruction of each subject's depth. The authors show that increasing the light source angle over the horizontal plane in the input image produces slight increases in reconstruction error, but increasing the ambient light proportion produces greater increases in reconstruction error. The authors applied the method to predict each subject's unknown depth using different individual reference models and an average reference model, which provides the best results. As a noise reduction technique, the authors perform a point by point weighted averaging with the average reference model with weights equal to the fractions of the squares of the Laplacian of a Gaussian applied to the prediction and to the reference depth over the sum of both. Finally, the authors present acceptable visual results obtained from external images of faces under arbitrary illumination, having performed an illumination estimation previously.

scholarly journals Statistical Modeling, Simulation, and Experimental Verification of Wideband Indoor Mobile Radio Channels

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yuanyuan Ma ◽  
Bjørn Olav Hogstad ◽  
Matthias Pätzold ◽  
Pedro M. Crespo
Keyword(s):  
Fading Channels ◽  
Experimental Verification ◽  
Communication Systems ◽  
Channel Model ◽  
Reference Model ◽  
Propagation Path ◽  
60 Ghz ◽  
Angle Of Arrival ◽  
Modeling Simulation ◽  
Channel Simulator

This paper focuses on the modeling, simulation, and experimental verification of wideband single-input single-output (SISO) mobile fading channels for indoor propagation environments. The indoor reference channel model is derived from a geometrical rectangle scattering model, which consists of an infinite number of scatterers. It is assumed that the scatterers are exponentially distributed over the two-dimensional (2D) horizontal plane of a rectangular room. Analytical expressions are derived for the probability density function (PDF) of the angle of arrival (AOA), the PDF of the propagation path length, the power delay profile (PDP), and the frequency correlation function (FCF). An efficient sum-of-cisoids (SOC) channel simulator is derived from the nonrealizable reference model by employing the SOC principle. It is shown that the SOC channel simulator approximates closely the reference model with respect to the FCF. The SOC channel simulator enables the performance evaluation of wideband indoor wireless communication systems with reduced realization expenditure. Moreover, the rationality and usefulness of the derived indoor channel model is confirmed by various measurements at 2.4, 5, and 60 GHz.

scholarly journals A 3D Non-Stationary Channel Model with Moving Mobile Station in Rectangular Tunnel

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zhicheng Ren ◽  
Fangqi Zhang ◽  
Guoxin Zheng ◽  
Asad Saleem ◽  
Ke Guan
Keyword(s):  
Correlation Function ◽  
Channel Model ◽  
Radio Channel ◽  
Three Dimensional ◽  
Mobile Station ◽  
Statistical Properties ◽  
Time Frequency ◽  
Doppler Power ◽  
Rectangular Tunnel ◽  
Stationary Channel

This paper presents a three-dimensional (3D) geometry-based stochastic model (GBSM) for capturing the non-stationarity of radio channel at 1.8 GHz in a rectangular tunnel. A time-variant (TV) complex channel gain is derived for obtaining the statistical properties in time, frequency, and spatial domains such as the time-variant autocorrelation function (TV-ACF), the time-variant Doppler power spectral density (TV-DPSD), and the time-variant spatial cross-correlation function (TV-CCF), respectively. Then the TV channel statistical properties at different time instants can be extracted and the non-stationary channel characteristics caused by the TV scattering environment are thoroughly discussed. Furthermore, three cases including “approach”, “arrival”, and “away” are set to allow a comprehensive study on how the DPSD behaves with the relative position between transmitter and receiver. The reliability of proposed 3D GBSM is highlighted by a good agreement with the measured result in terms of the correlation function.

scholarly journals Characteristic Analysis on UAV-MIMO Channel Based on Normalized Correlation Matrix

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Gao Xi jun ◽  
Chen Zi li ◽  
Hu Yong Jiang
Keyword(s):  
Correlation Matrix ◽  
Channel Model ◽  
Three Dimensional ◽  
Matrix Decomposition ◽  
Mimo Channel ◽  
Characteristic Analysis ◽  
Channel Correlation ◽  
Channel Matrix ◽  
Time Frequency ◽  
Model Channel

Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication.

scholarly journals Design of Wideband MIMO Car-to-Car Channel Models Based on the Geometrical Street Scattering Model

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Nurilla Avazov ◽  
Matthias Pätzold
Keyword(s):  
Correlation Function ◽  
Communication Systems ◽  
Channel Model ◽  
Reference Model ◽  
Multiple Input Multiple Output ◽  
Measurement Data ◽  
Scattering Model ◽  
Time Frequency ◽  
Comparison Results ◽  
Channel Simulator

We propose a wideband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on the geometrical street scattering model. Starting from the geometrical model, a MIMO reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. The proposed channel model assumes an infinite number of scatterers, which are uniformly distributed in two rectangular areas located on both sides of the street. Analytical solutions are presented for the space-time-frequency cross-correlation function (STF-CCF), the two-dimensional (2D) space CCF, the time-frequency CCF (TF-CCF), the temporal autocorrelation function (ACF), and the frequency correlation function (FCF). An efficient sum-of-cisoids (SOCs) channel simulator is derived from the reference model. It is shown that the temporal ACF and the FCF of the SOC channel simulator fit very well to the corresponding correlation functions of the reference model. To validate the proposed channel model, the mean Doppler shift and the Doppler spread of the reference model have been matched to real-world measurement data. The comparison results demonstrate an excellent agreement between theory and measurements, which confirms the validity of the derived reference model. The proposed geometry-based channel simulator allows us to study the effect of nearby street scatterers on the performance of C2C communication systems.

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