Source information transmission over MIMO systems with transmitter side information

We consider strategies for the lossy transmission of a zero-mean memoryless Gaussian source over a 2 × 2 Rayleigh faded MIMO system with transmitter side information. The first strategy uses repetition coding, where the same symbol is duplicated over the two transmit antennas in two consecutive time slots. The second strategy employs the Alamouti scheme, while the third strategy is based on spatial multiplexing. A mean squared error distortion measure is assumed. Since this distortion results, at the receiver, in a continuous random variable, both its expected value and statistical distribution are used for evaluating the performance of each strategy. It is shown that the spatial multiplexing strategy achieves the lowest expected distortion and also that the utilization of the Alamouti strategy brings only a slight decrease in performance, but has the advantage of a lower realization complexity. Considering the statistical distributions of distortion, it is observed that increasing the signal-to-noise ratio results in higher probabilities of achieving the expected distortion and to less variable values of distortion. Due to the characteristics of the respective distri- butions of distortion, both Alamouti and spatial multiplexing strategies are capable of achieving low distortion with high probability while, at the same probability, the repetition stachieves significantly higher distortion.