—This paper simulates a typical indoor MIMO-UWB OFDM system using computational electromagnetics. The goal is to create a simulation using a real world environment and taking into account realistic antenna effects. The effects of the wireless channel are examined on a per subcarrier basis. Analysis of the simulation results shows that the channel response and subsequently, mutual information is highly dependent on subcarrier. Furthermore, our analysis shows that by taking advantage of channel knowledge, a great increase in mutual information can be obtained. This leads to the conclusion that adaptive modulation has the potential to offer significant increase in system capacity.