Extended Geometrically Based Single Bounce Elliptical Model (GBSBEM) for Indoor Line-Of-Sight (LOS) MIMO Channel Using Polarization Diversity at 8 GHz bands

摘要

The MIMO is receiving considerable attention since next generation of wireless systems are expected to support high data rates. As well known, the MIMO capacity is linearly increasing with the minimum of the number of transmit and receive antennas [1]. However handheld devices restrict antenna spacing which is needed for low correlation between antennas. The use of cross-polarized antennas for MIMO systems is interested recently because cross-polarized antennas are able to double the antenna numbers for half the spacing needs of co-polarized antennas. Addition to that, cross-polarized MIMO system has more capacity due to low correlation for same antenna spacing. In order to study and compare various receiver architectures for MIMO system, one needs to have an accurate knowledge of the MIMO channel and develop the channel model to describe realistic channel exactly. On the other hands, many wireless communication systems have been launched and many researches have been worked below 5 GHz bands. However, frequency bands below 5 GHz are saturated and very few studies have appeared that characterize indoor MIMO channel using polarization diversity beyond 5 GHz bands. Although Winner generic channel model [2] and 3-D SCM (Spatial Channel Model) [3] are proposed for cross-polarized MIMO channel, those don't consider difference of indoor environments. In other words, change of channel characteristics corresponding to indoor environments are not reflected upon. Also, those are not suitable for 8 GHz bands since those use the spatial parameters which measured at 2 GHz and 5 GHz bands. In this paper, extended GBSBEM is proposed for indoor LOS MIMO channel using polarization diversity at 8 GHz bands. The proposed model can create spatial channel parameters for each environment. It extends to have 3-dimensional geometry for indoor environment and consider array antennas using spatial correlation, also. In addition, scattering mechanism as well as reflection is considered using the patch scattering model [4]. And to verify the proposed model results, which measured at small office room and corridor, are compared with simulated results.