On the Ergodic Mutual Information of Multiple Cluster Scattering MIMO Channels

We consider multiple cluster scattering MIMO channels, where the effective channel equals the product of n complex Gaussian matrices. The considered channel model is typical for picocell propagation environments. For this channel model, we derive a closed-form lower bound of the ergodic mutual information. The derived lower bound is asymptotically tight, and is valid for an arbitrary number of clusters n - 1 and an arbitrary number of antennas. The scaling law of the ergodic mutual information is found, generalizing the known result for the conventional MIMO channel model for which n = 1.