  We determine the capacity-achieving input covariance matrices for coherent
block-fading correlated MIMO Rician channels. In contrast with the Rayleigh and
uncorrelated Rician cases, no closed-form expressions for the eigenvectors of
the optimum input covariance matrix are available. Both the eigenvectors and
eigenvalues have to be evaluated by using numerical techniques. As the
corresponding optimization algorithms are not very attractive, we evaluate the
limit of the average mutual information when the number of transmit and receive
antennas converge to infinity at the same rate. If the channel is
semi-correlated, we propose an attractive optimization algorithm of the large
system approximant, and establish some convergence results. Simulation results
show that our approach provide reliable results even for a quite moderate
number of transmit and receive antennas.
