On achieving exponential diversity with partial channel state information in MIMO fading channels

In this paper we derive conditions under which exponential diversity can be achieved when the quality of channel state information degrades. We show that exponential diversity is obtained if and only if the variance of the noise corrupting the CSIT is (atleast) inversely proportional to SNR and the channel estimate is obtained at a transmit power greater than or equal to the power to be allocated. Simulation results, corroborating the theoretical analysis are presented for Rayleigh fading channels.