Performance analysis and optimization of switched transmit diversity in MIMO systems

We propose a new switched transmit diversity technique in MIMO systems with an application to Alamouti's space time block coding. The proposed scheme is basically a closed loop system where the feedback bits are sent back to the transmitter to indicate the channel quality. Various switching strategies, depending on the size of feedback bits, are considered and optimized to compare the trade-off between the link performance and the number of antennas or feedback information. From our analytical and numerical results, we show that there is a considerable benefit in terms of the performance and practical use.