MIMO Channel Capacity in Co-Channel Interference

In this paper we investigate the performance of MIMO systems in co-channel interference. We present a way of explicitly examining the effect of interference on the MIMO sub-channel gains. Using this, we derive upper and lower asymptotic bounds on capacity with many interferers and in high interference-to-noise ratio. Simulation results are presented for these bounds and for the performance of MIMO systems in a variety of situations as a function of the number of cochannel interferers and as a function of interference-to-noise ratio. Unusually, it is seen that, with a slight modification of the MIMO channel matrix to incorporate interference, higher correlation in the channel yields higher capacity. We also simulate the effect of a priori knowledge of the channel and interference covariance at the transmitter and evaluate the capacity gain that such knowledge offers.