MIMO capacity variation with SNR and multipath richness from full-wave indoor FDTD simulations

We demonstrate the joint effect of path loss and multipath richness on capacity through two-dimensional finite-difference time-domain simulations The scenario under study is a simplified model of a section of the 4th floor of an engineering building. We find that multipath richness is fairly constant, and that the capacity is mostly a function of the path loss. A capacity multiplier analysis shows that when average SNR in the environment is high, MIMO systems tend to be very advantageous. However, when average SNR is low, most of the advantage of the multiple antennas comes from diversity and not spatial multiplexing.