Comparison of three closed-loop transmit diversity schemes

In this paper several closed-loop transmit diversity schemes with different levels of feedback about the channel coefficients to the transmitter side are described and compared. These schemes are transmit beamforming with perfect channel state information (CSI) at the transmitter, transmit antenna selection/maximal-ratio combining (TAS/MRC) and the transmit antenna selection/space-time block code (TAS/STBC) schemes with partial CSI available at the transmitter. It is shown that the TAS/MRC scheme provides a good trade-off between feedback complexity and performance.