Abstract : At present, there is a high demand for an increasing data rate transmission over wireless communication systems, in order to serve a recent development of multimedia applications on terminals. In 1996, one important technique was proposed by Bell laboratory researchers in order to improve data throughput and quality without increasing additional bandwidth and power of transmission. The basic aim of this technique is to create the independent sub-channels by using multiple antennas at the transmitter and receiver sides (MIMO). However, MIMO systems suffer from the correlation between the sub-channels that might occur, especially, when the distance between antennas is limited and when the angular spread is narrow. This incident affects the performance of MIMO systems. Therefore, the main objective of this thesis is to implement a MIMO system with polarization diversity so as to reduce the correlation between the sub-channels under physical limitation of antenna array size.
The research presented in this thesis is composed of three main parts. First of all, a three dimensional modelling of the MIMO transmission channel is proposed. In order to accurate the channel, was taken into account the characteristic of the antenna polarization. Secondly, the channel capacity for the multiple antenna systems employing single polarized antennas is examined. Finally, we extend our study by focusing on the multiple antenna systems with the polarization diversity such as MIMO systems with double polarization, triple polarization and sextuple polarization.