A radio communication system and scheduling method where, when data are transmitted from a plurality of transmit antennas to respective different mobile station apparatuses, all the mobile station apparatuses precisely receive data addressed thereto. A scheduler (104) performs scheduling that determines a data transmit order, depending on the numbers of receive antennas of the respective mobile station apparatuses, and notifies a transmit antennas assignment signal generator (124) of which transmit antenna is assigned which mobile station apparatus's sub-stream as the scheduling result. A number of receive antennas notifying signal decoder (122) decodes the number of receive antennas notifying signals and notifies the number of the receive antennas of each mobile station apparatus to the scheduler (104). The transmit antennas assignment signal generator (124) generates the transmit antennas assignment signal indicating which transmit antenna is assigned which mobile station apparatus's sub-stream.