Patent ID: 8654724

Claim:
A base station apparatus which serves as a second base station apparatus in a radio communication system, the radio communication system including a mobile station apparatus, a first base station apparatus and a second base station apparatus, the mobile station apparatus receiving downlink data that is transmitted in a downlink data region of the first base station apparatus and transmitting uplink data in an uplink data region of the second base station apparatus, the base station apparatus comprising; an arrangement section that arranges a first control signal containing scheduling information of the uplink data for the mobile station apparatus in a part of the downlink data region of the first base station apparatus, the downlink data region being different from a downlink control channel of the first base station apparatus, in which a second control signal containing scheduling information of the downlink data for the mobile station apparatus is arranged at the first base station apparatus; and a transmission section that transmits the first control signal to the mobile station apparatus.