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Precoders permits to enhance the performance of MIMO systems by optimizing a pertinent criterion of the transmission. For example, the max-dmin precoder optimizes the minimum Euclidean distance of the received constellation. In this paper, we evaluate the performance of max-dmin in a realistic time-variant channel for both spectral efficiency (4 and 8 bit/s/Hz). The channel is obtained by a 3D Propagation...
In this paper we propose to analyze the impact of the facets, constituting a railway dynamical environment, on the electromagnetic wave propagation mechanisms. This study allows reducing the computation times of a radio wave propagation simulator based on ray tracing. The obtained results drive to gain in computation time higher than five.
This paper presents, in a first time, an original method of smart antenna design, based on an antenna array driven by vector modulators. Different radiation patterns are measured to validate the method. In a second time, we show the interest in using such antenna array in transports domain. Thus, we first integrate these radiation patterns into a 3D propagation simulator based on Ray-Tracing, to achieve...
Mutual coupling effect between antennas on MIMO (multiple input multiple output) transmission is an important factor to take into account for an accurate modelling channel when antennas are closely spaced. The aim of this paper is to present the impact of mutual coupling on MIMO channel characteristics according to several propagation contexts. To achieve this purpose an original study, which has...
One of the important factors for deterministic channel propagation simulator using 3D ray-tracing methods is the environment modeling. Sensitivity of results depends on its description accuracy. This paper concerns the influence of the environment description precision on MIMO channel characterization. Simulations have been performed in two unfurnished indoor environments. The first one is a floor,...
The current wireless systems evolve towards multimedia applications demanding more and more high bit rate. Consequently, we observe an important rise in frequency. Then, it becomes necessary to study the influence of particular details of environment such as rough surfaces or small and complex scattering structures. Nowadays, ray tracing techniques, based on the geometrical optic (OG) and the uniform...
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