Exponential diversity achieving spatio-temporal power allocation scheme for MIMO fading channels

We analyze optimum (space-time) adaptive power transmission policies for Rayleigh fading MIMO channels when CSIT and CSIR are available. We show that our power allocation policy provides exponential diversity gain² (BER≤αe^{-f(n(t),n(r))} where α>0 is a constant, and f>0 is an increasing function of n_t&n_r) if perfect CSIT is available. Exponential diversity is lost at high SNR if the quality of CSIT degrades.