Tight upper bound on the ergodic capacity of the Rician fading MIMO channels

The ergodic capacity of a multiple antenna system in Rician fading is considered under the assumption that channel state information (CSI) is available only at the receiver and the transmitter has no knowledge of the CSI. Using complex non-central Wishart distribution and Bartlett´s decomposition, we derive a tight closed-form upper bound on the ergodic capacity of such channels. We show that our bound is tighter than previously reported analytical bound. Moreover, we provide an approximation of ergodic capacity in high-SNR regime. Numerical results also show that our results closely match the actual ergodic capacity of Rician fading MIMO channels.