3,104 research outputs found
3D spatial fading correlation for uniform angle of arrival distribution
We derive a closed-form expression for the spatial fading correlation (SFC) between two arbitrary points in 3D-space for the uniform limited azimuth-elevation angle of arrival probability density function (pdf). This expression simplifies the computatio
A Generalized Spatial Correlation Model for 3D MIMO Channels based on the Fourier Coefficients of Power Spectrums
Previous studies have confirmed the adverse impact of fading correlation on
the mutual information (MI) of two-dimensional (2D) multiple-input
multiple-output (MIMO) systems. More recently, the trend is to enhance the
system performance by exploiting the channel's degrees of freedom in the
elevation, which necessitates the derivation and characterization of
three-dimensional (3D) channels in the presence of spatial correlation. In this
paper, an exact closed-form expression for the Spatial Correlation Function
(SCF) is derived for 3D MIMO channels. This novel SCF is developed for a
uniform linear array of antennas with nonisotropic antenna patterns. The
proposed method resorts to the spherical harmonic expansion (SHE) of plane
waves and the trigonometric expansion of Legendre and associated Legendre
polynomials. The resulting expression depends on the underlying arbitrary
angular distributions and antenna patterns through the Fourier Series (FS)
coefficients of power azimuth and elevation spectrums. The novelty of the
proposed method lies in the SCF being valid for any 3D propagation environment.
The developed SCF determines the covariance matrices at the transmitter and the
receiver that form the Kronecker channel model. In order to quantify the
effects of correlation on the system performance, the information-theoretic
deterministic equivalents of the MI for the Kronecker model are utilized in
both mono-user and multi-user cases. Numerical results validate the proposed
analytical expressions and elucidate the dependence of the system performance
on azimuth and elevation angular spreads and antenna patterns. Some useful
insights into the behaviour of MI as a function of downtilt angles are
provided. The derived model will help evaluate the performance of correlated 3D
MIMO channels in the future.Comment: Accepted in IEEE Transactions on signal processin
MIMO Channel Correlation in General Scattering Environments
This paper presents an analytical model for the fading channel correlation in
general scattering environments. In contrast to the existing correlation
models, our new approach treats the scattering environment as non-separable and
it is modeled using a bi-angular power distribution. The bi-angular power
distribution is parameterized by the mean departure and arrival angles, angular
spreads of the univariate angular power distributions at the transmitter and
receiver apertures, and a third parameter, the covariance between transmit and
receive angles which captures the statistical interdependency between angular
power distributions at the transmitter and receiver apertures. When this third
parameter is zero, this new model reduces to the well known "Kronecker" model.
Using the proposed model, we show that Kronecker model is a good approximation
to the actual channel when the scattering channel consists of a single
scattering cluster. In the presence of multiple remote scattering clusters we
show that Kronecker model over estimates the performance by artificially
increasing the number of multipaths in the channel.Comment: Australian Communication Theory Workshop Proceedings 2006, Perth
Western Australia. (accepted
ns-3 Implementation of the 3GPP MIMO Channel Model for Frequency Spectrum above 6 GHz
Communications at mmWave frequencies will be a key enabler of the next
generation of cellular networks, due to the multi-Gbps rate that can be
achieved. However, there are still several problems that must be solved before
this technology can be widely adopted, primarily associated with the interplay
between the variability of mmWave links and the complexity of mobile networks.
An end-to-end network simulator represents a great tool to assess the
performance of any proposed solution to meet the stringent 5G requirements.
Given the criticality of channel propagation characteristics at higher
frequencies, we present our implementation of the 3GPP channel model for the
6-100 GHz band for the ns-3 end-to-end 5G mmWave module, and detail its
associated MIMO beamforming architecture
Impact of Line-of-Sight and Unequal Spatial Correlation on Uplink MU-MIMO Systems
Closed-form approximations of the expected per-terminal
signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral
efficiency of a multiuser multiple-input multiple-output system are presented.
Our analysis assumes spatially correlated Ricean fading channels with
maximum-ratio combining on the uplink. Unlike previous studies, our model
accounts for the presence of unequal correlation matrices, unequal Rice
factors, as well as unequal link gains to each terminal. The derived
approximations lend themselves to useful insights, special cases and
demonstrate the aggregate impact of line-of-sight (LoS) and unequal correlation
matrices. Numerical results show that while unequal correlation matrices
enhance the expected SINR and ergodic sum spectral efficiency, the presence of
strong LoS has an opposite effect. Our approximations are general and remain
insensitive to changes in the system dimensions, signal-to-noise-ratios, LoS
levels and unequal correlation levels.Comment: 4 pages, 2 figures, accepted for publication in the IEEE Wireless
Communications Letters, Vol. 6, 201
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