MIMO capacity gain analysis for general channel models

In this paper, we evaluate the capacity gains offered by MIMO systems relative to SISO by using two metrics: the ratio between the expected value of the two capacities and a weighted difference between the two capacities. We present results for these metrics for the case of a general channel, where fading could be iid, correlated Rayleigh, or any other type. We derive limiting values of the capacity metrics for low and high SNR and show via simulation their behavior at other values of SNR. These simulations provide valuable insight into the variation of the capacity metrics in the important SNR range from -5 dB to 20 dB which is commonly observed in cellular systems.