An Upper-Bound on the Ergodic Capacity of Rayleigh-Fading MIMO Channels using Majorization Theory

In this paper, we investigate the ergodic capacity of multiple-input multiple-output (MIMO) wireless communication systems over spatially uncorrelated Rayleigh-fading channels, assuming that the channel state information (CSI) is unknown at the transmitter and perfectly known at the receiver. Applying some results of majorization theory, we provide an analytical closed-form upper-bound to the ergodic capacity at any signal- to-noise ratio (SNR). In addition, we also derive an approximation to the ergodic capacity in high-SNR regimes. Finally, we present numerical results that confirm our theoretical analysis.