Multiple-antenna capacity in a deterministic Rician fading channel

We calculate the capacity of a multiple-antenna wireless link in a Rician fading channel. We consider the standard Rician fading channel where the channel coefficients are modeled as independent circular Gaussian random variables with non-zero means (non-zero specular component). The channel coefficients of this model are constant over a block of T symbol periods but, independent over different blocks. For such a model, the capacity and capacity achieving signals are dependent on the specular component. We obtain asymptotic expressions for capacity in the low and high SNR scenarios. We also consider the capacity of the wireless system that uses pilot symbol-based training to estimate the channel. We establish that for low SNR the specular component of channel coefficients completely determines the form of the optimum signal whereas for high SNR it has no effect on the optimum signal structure. We further conclude that beamforming is the optimum signaling strategy for low SNR whereas for high SNR the optimum Signal structure is same as that for purely Rayleigh fading channels.