Disclosed are a MIMO communication system and a method of controlling the same. The MIMO communication system includes an MCS (modulation and coding scheme) level selector for selecting an MCS level representing combination of data modulation and coding schemes according to a channel status, a modulation and coding section for processing transmit data according to modulation and coding schemes corresponding to the selected MCS level, a D-STTD (double-space time transmit diversity) encoder for coding the transmit data, which has been processed through the modulation and coding section, through a D-STTD scheme and transmitting the transmit data through M transmit antennas, and a receiver for receiving data, which have been coded through the D-STTD scheme, through N receive antennas, detecting the received data through an OSIC-MMSE (ordered successive interference cancellation-minimum mean-square error) scheme, and decoding the received data through the modulation and coding schemes employed in the modulation and coding section.