Achieving exponential diversity with SpatioTemporal power allocation with imperfect channel state information

In this paper we derive conditions under which Spatio-temporal power allocation provides exponential diversity when the quality of channel state information at the transmitter (CSIT) and receiver (CSIR) degrades. We show that exponential diversity is obtained provided two conditions are satisfied; 1)the feedback rate increases linearly with the signal-to-noise ratio (SNR) and 2) 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