Rate-Optimal MIMO Transmission with Mean and Covariance Feedback at Low SNRs

This paper considers a multiple-input–multiple-output (MIMO) wireless communication scenario in which the channel follows a block-fading model with a general spatially correlated complex Gaussian distribution with nonzero mean. We derive an explicit characterization of the (ergodic) rate-optimal input covariance for systems that operate at low signal-to-noise ratios (SNRs). In particular, we obtain a closed-form expression for the matrix whose …