Characterization of the impact of power normalization on the MIMO mutual information

Abstract

In this paper, we investigate the impact of power normalization on the mutual information of Multiple-Input Multiple-Output (MIMO) systems. We quantify the difference in the mutual information when using two different power normalization methods – corresponding to slow and fast power control – and characterize this difference in the high SNR regime in terms of its distribution, mean and variance. We assume Rayleigh fading channels with perfect channel state information at the receiver. Also, we assume equal power allocation strategy is applied at the transmitter. It turns out that the difference in mutual information is governed by the temporal variations of the SNR. In MIMO systems, the inherent spatial diversity of the channel makes the difference negligible in Rayleigh fading environments.