On strategies for source information transmission over MIMO systems

We consider strategies for the lossy transmission of a zero mean Gaussian source over a 2x2 MIMO channel with Rayleigh fading. The source is represented either using a single description or a multiple description code, depending on each strategy characteristic. Performance is evaluated using normalized expected distortion at the receiver, as a function of outage probability. The first strategy employs repetition coding over the two transmit antennas for the transmission of a single description representation of the source. The second strategy uses a time-shared approach to the two transmit antennas, allowing for the transmission of a multiple description representation of the source. The third and fourth strategies are based on, respectively, the Alamouti scheme and spatial multiplexing, and both of these strategies are used for the transmission of a single description representation of the source. The results show that the spatial multiplexing strategy is able to achieve the lowest distortion, and also that it is possible, with the Alamouti strategy, to obtain similar performance at a lower complexity. We finally consider the outage rates of the different strategies and observe that if a system is designed to maximize the outage rate, the corresponding distortion observed at the receiver will not be minimized.