Transmit Diversity for Arrays in Correlated Rayleigh Fading

Transmit diversity is usually presented for the case of independently faded channels. In this paper the structure of a linear transmitter that can be optimized for a Rayleigh-fading environment in which the fading may be correlated is derived. The transmitter achieves the best mix of array gain-obtained by beamforming, and diversity gain-obtained by using multiple transmit beamformers and space-time coding. The authors use a multiinput single output (MISO) transmitter and receiver structure to present a detailed performance analysis, that shows the array gain versus diversity gain tradeoff as the fading correlation changes. This analysis is validated by simulation results.