MIMO Channel Capacity in Co-Channel Interference

Recent information theory results have indicated that a large channel capacity exists for wireless systems with multiple transmit and receive antennas. With different assumptions of channel knowledge and interference knowledge at the transmitter, the channel capacity of multiple input multiple output (MIMO) systems has been studied under both spatially white and colored interference and noise. In this paper, we fix the total interference-plus-noise power and evaluate the outage capacity under two spatially colored interference environments: (1) a few high-data-rate interferers each with high power, (2) a large number of lowdata-rate interferers each with low power. The results show that MIMO capacity is larger with fewer high-data-rate interferers. We also assess the impact of an estimated channel and/or interference on capacity. In the case of 4 transmit and 4 receive antennas for the user of interest, 10 interferers, total-interference-to-noise ratio and signal-to-noise ratio are both 20dB, the results show that it is beneficial to estimate the channel and/or interference if the variance of estimation error is less than about 50% of the variance of true channel and/or interference.