A radio communication system, a radio communication control method, a radio communication apparatus, a control method for a radio communication apparatus, and a computer program make it possible to minimize the chance of co-channel interference in a multi-cell environment, and also permit free adjustment of an uplink/downlink ratio. The carrier sense region of a terminal wanting an uplink shares the region used as a directional busy tone region for a terminal wanting an uplink, and the region used as a reference signal transmission region of a terminal wanting a downlink. Furthermore, the carrier sense region of a terminal wanting a downlink shares the region used as a directional busy tone region for a terminal wanting a downlink, and the region used as a reference signal transmission region of a terminal wanting an uplink. If a result of the carrier sense indicates an idle mode, then a reference signal is transmitted.