Orthogonal Space-Time Block Coding with Adaptive Transmit Diversity for Correlated MIMO Channels

In this paper we introduce a technique of eigenbeamforming based on the channel correlation matrix and paired with orthogonal space-time code (O-STBC) at the transmitter side of the link. This structure combines the spatial signal paths decorrelation with the diversity gain provided by the space-time code, which results in performance improvement. The probability distributions for both bit-error-rate (BER) and symbolerror-rate (SER) are presented based on the received signal-to-noise ratio (SNR) for this system. The system has been simulated using four transmit antennas in both uncorrelated and correlated channels. Results showed that the proposed scheme provides a significant improvement in the error rate performance of spatially correlated channels. Key-Words: Adaptive beamforming, space-time channel, MIMO, transmit diversity, block coding