A new transmit diversity analysis for noncoherent space-time modulation

A new statistics method is developed to evaluate the diversity gain for multiple-antenna communication links in block flat-fading environments. The unitary space-time signal, which has been proved to achieve a high channel capacity in Rayleigh flat-fading environments, is proved to be a special case of this method. The variance of the receive power and its relationship with transmit diversity are studied. A diversity gain measurement based on the variance of receive power is defined and the theoretical expression is derived. The signal structures that can achieve the maximum and minimum diversity are calculated. The results not only can be applied to the Rayleigh channel, but can also be used in the general channel conditions discussed in this paper.