There is provided a Multi-Input Multi-Output (MIMO) communication system including a transmitter for combining at least four transmit antennas according to each of at least two sub-channels, and transmitting space-time-coded signals and at least one receiver for receiving the signals through at least two antennas, wherein the receiver includes an antenna coordination information generator for generating and feeding back optimal transmit antenna coordination information according to said each sub-channel by means of the received signals, and the transmitter includes an antenna coordination controller for controlling coordinations of the transmit antennas according to each sub-channel based on the transmit antenna coordination information fed back from the receiver.