Analysis of the Local Quasi-Stationarity of Measured Dual-Polarized MIMO Channels

It is common practice in wireless communications to assume strict or wide-sense stationarity of the wireless channel in time and frequency. While this approximation has some physical justification, it is only valid inside certain time-frequency regions. This paper presents an elaborate characterization of the non-stationarity of wireless dual-polarized channels in time. The evaluation is based on urban macrocell measurements performed at 2.53 GHz. In order to define local quasi-stationarity (LQS) regions, i.e., regions in which the change of certain channel statistics is deemed insignificant, we resort to the performance degradation of selected algorithms specific to channel estimation and beamforming. Additionally, we compare our results to commonly used measures in the literature. We find that the polarization, the antenna spacing, and the opening angle of the antennas into the propagation channel can strongly influence the non-stationarity of the observed channel. The obtained LQS regions can be of significant size, i.e., several meters, and thus the reuse of channel statistics over large distances is meaningful (in an average sense) for certain algorithms. Furthermore, we conclude that, from a system perspective, a proper non-stationarity analysis should be based on the considered algorithm

On the capacity of printed planar rectangular patch antenna arrays in the MIMO channel: Analysis and measurements

Printed arrays of rectangular patch antennas are analyzed in terms of their MIMO performance using a full-wave channel model. These antennas are designed and manufactured in various array configurations, and their MIMO performance is measured in an indoor environment. Good agreement is achieved between the measurements and simulations performed using the full-wave channel model. Effects on the MIMO capacity of the mutual coupling and the electrical properties of the printed patches, such as the relative permittivity and thickness of the dielectric material, are explored. © 2006 IEEE

Channel Estimation in MIMO Radar Environment

Now these days, the increasing demands of channel capacity attract the researcher to work in this direction. The algorithms which are used to increase the channel capacity is nothing but a smart and cleaver coding work. The cleaver coding of data is done in time and space. These coding work use multipath structure. To work on the channel capacity we required good and detail knowledge about the channel. In this work our basic aim is to estimate the channel in an MIMO wireless environment. So the overview of a basic estimate technics is given here. In this work we estimate different channel parameters such as amplitude and phase and the results are compared with the ideal parameters. Here Maximum Likelihood Technique (MLE) is used to estimate the channel parameters