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

Jun Chen,Thomas G Pratt

doi:10.1155/2012/756508

Abstract

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.

Highlights

For nearly two decades, multiple-input-multiple-output (MIMO) communications systems [1,2,3] have been rigorously studied, leading to the adoption of MIMO in a number of wireless communications standards such as Long Term Evolution (LTE) and 802.11n
The results indicate that the timefrequency correlation functions (TFCFs) are not separable into a product of a time correlation function and a frequency correlation function, a conclusion that we anticipated since the scatter locations contribute to both the time dispersion and the Doppler spread
A 3D geometrical propagation model has been proposed for DP-MIMO mobile-to-mobile Rayleigh and Rician fading channels

Summary

Introduction

Multiple-input-multiple-output (MIMO) communications systems [1,2,3] have been rigorously studied, leading to the adoption of MIMO in a number of wireless communications standards such as Long Term Evolution (LTE) and 802.11n. The 3D scattering propagation model used to evaluated the TFCFs simulates the effects of the antenna pattern gains, the geometrical distribution of scatterers and the associated azimuth/elevation angles of arrival and departure, the K-factor of the fading distributions, the maximum Doppler frequency, the scattering loss factors, the crosspolar discrimination (XPD), and the copolarization ratio (CPR). The XPD depends on channel parameters and the environment, such as the distance between the Tx and the Rx, the angles of arrival and departure (both azimuth and elevation), the delay spread of the multipath components, and the transmit and receive antenna polarization basis. + TDabB t, f + TLabOS t, f , where TSaBbT(t, f ), TSaBbR(t, f ), TDabB(t, f ), and TLabOS(t, f ) (a ∈ {p, p}, b ∈ {q, q}) are time-variant transfer functions for the SBT, SBR, DB and LOS components, respectively

Polarization Matched Time-Frequency Correlation Functions

Numerical Results and Analysis

Conclusion