Abstract: Based on multi-user Multiple Input Multiple Output（MIMO） systems，the impact of a few interferers each with high power and a large number of interferers each with low power on system capacity with fixed co-channel interference power are analyzed.Then the system capacities as a function of the number of interference users and Interference-Noise Ratio（INR） under the two above conditions are given.Finally，Monte Carlo simulations are done to simulate the system capacities which are compared with the theory system capacities under different conditions.The results show the relationships between outage capacities and the number of interference users，transmit antennas of each interference user and INR，which can act as a guidance in MIMO system design.

Key words: channel capacity, co-channel interference, interference to noise ratio, multiple input multiple output

摘要： 针对多用户环境下的多输入多输出（MIMO）系统容量问题，分别分析了同频干扰功率一定时，多干扰用户，小功率发射和少干扰用户，高功率发射对系统容量的影响，给出了两种条件下，系统容量与干扰用户数目以及干扰噪声比的函数关系。最后用蒙特卡洛方法仿真了系统的中断容量，并与不同情况下中断容量的理论曲线相比较，得出了干扰用户数目，干扰用户天线数目以及INR与系统中断容量的关系，用以指导MIMO系统级设计。

关键词: 信道容量, 同频干扰, 干扰噪声比, 多输入多输出