In this chapter, we study transmit diversity scheme employed in multipleinput,
multiple-output (MIMO) systems and analyze its performance theoretically in
random fading channels under different conditions, e.g. with and without spatial correlations,
with and without transmit antenna selection. The transmit diversity scheme
in its original form does not take the frequency selectivity of the channel into account,
therefore it has to be modified in order to be applicable for real life applications. To
this end, we introduce two solutions to combat the intersymbol interference caused by
frequency selective channels and in the meantime, exploit the spatial and multi-path diversities
with simple linear processing at the receiver. We aim at providing readers with
a comprehensive view on different aspects of MIMO transmit diversity and a practical
guideline on how to design a wireless communication system with transmit diversity.
Keywords: MIMO, transmit diversity, space-time Trellis coding, space-time coding, orthogonal space-time block code
