In this paper, channel capacity of multiple-input multiple-output wireless local area network (MIMO-WLAN) systems with single co-channel interference (CCI) is calculated. A ray-tracing approach is used to calculate the channel frequency response, which is further used to calculate the corresponding channel capacity. The ability to combat CCI for the MIMO-WLAN simple uniform linear array (ULA) and polarization diversity array (PDA) are investigated. Also the effects caused by two antenna arrays for desired system and CCI are quantified. Numerical results show that MIMO-PDA is better than those of MIMO-ULA when interference is present.