| This thesis considers both an analysis and a numerical evaluation of the performance of MIMO radio systems in the LTE network environment. More specifically we consider the physical layer of the OFDM-MIMO based radio interface. As a first step we present a theoretical analysis of the bit error rate of the two space-time codes adopted by the LTE norm, namely the SFBC 2 x 1 and FSTD 4 x 2 codes, as a function of the signal upon noise ratio. Analytical expressions are given for transmission over a Rayleigh channel without spatial correlation which are then compared with Monte-Carlo simulations. As a second step, we consider the capacity of the channel obtained by using these codes on a Rayleigh fading channel. Results show that simulated throughput almost reaches the capacity limit. As a different topic, this thesis considers also MIMO systems based on antenna selection. By using order statistics we develop analytical expressions for the error rate on a Rayleigh channel without antenna correlation. In order to validate our numerical results, an algorithm implementing antenna selection at the receiver has been developed and used in the simulations. As a last step the effect of antenna correlation is investigated through the use of simulations and a model of spatial antenna correlation based on the Kronecker product of two correlation matrices related to the transmitting and receiving elements of the MIMO scheme. |
