Utilizing quantized feedback information in orthogonal space-time block coding

Recently, space-time codes have been developed that achieve a large portion of the capacity available in communication systems equipped with multiple transmit and receive antennas. These codes are designed under the assumption that the transmitter has no knowledge about the channel In this work, on the other hand, we consider how the presence or vector quantized channel information obtained from a feed back link may be utilized for improving the performance of a space-time code. The transmission scheme we propose takes the non-perfect nature of the channel information into account while combining the benefits of conventional beamforming with those given by orthogonal space-time block codes. Simulation results demonstrate significant gains over conventional methods and also robustness to feedback channel errors.