A method of controlling signal transmission in a Multiple Input Multiple Output (MIMO) communication system including selecting a modulation and code set (MCS) for each of M data streams transmitted via M transmitting antennas in a transmitting side of the MIMO system, and selectively selecting M−1 or fewer transmitting antennas from the M transmitting antennas for transmitting the data streams based on channel quality information indicative of a transmission performance of the selected MCS corresponding to each of the M transmitting antennas. In another example, the present invention provides a novel method of controlling signal transmission in a MIMO communication system including selecting M weight vectors for streams transmitted by each of M transmitting antennas in a transmitting side of the MIMO system, and selectively selecting M−1 or fewer streams and weight vectors from the M weight vectors for transmitting data streams based on channel quality information indicative of transmission performance of the selected weight vectors corresponding to each of the M vector spaces.