Abstract: A wireless communication apparatus includes a base station having M antennas to communicate with K user terminals through a wireless channel. The base station includes a data rate information recoverer for recovering from feedback signals received from the K user terminals data rate information indicating an available data rate of each subchannel from the M antennas; a subchannel and data rate assignment information generator for assigning the M subchannels to the K user terminals according to the data rate information and determining data rates of the assigned subchannels; and a transmitter for transmitting data for the selected M user terminals to the M user terminals via the assigned M antennas at the determined data rates. If K is greater than or equal to M, the subchannel and data rate assignment information generator assigns the M subchannels to the M user terminals selected from the K user terminals on a round robin basis, in each time slot.