Patent ID: 8046021

Claim:
A communication system including a control station and a plurality of dependent stations, wherein said control station of a first network includes an instruction unit configured to instruct a dependent station to transmit a predetermined signal; a reception unit configured to receive a signal which is transferred by the dependent station, wherein the signal has been received by the dependent station from a second network; a determination unit configured to determine based on the signal received by said reception unit whether a device of the second network has received the predetermined signal which has been transmitted by the dependent station, and a controlling unit configured to control transmission power of a first dependent station when the determination unit determines that the device of the second network has received the predetermined signal which has been transmitted by the dependent station, and said first dependent station includes a first transmission unit configured to transmit the predetermined signal in accordance with instruction of said control station; a second transmission unit configured to transfer the signal to said control station, which is transmitted by the device of the second network after the first transmission unit transmits the predetermined signal; a control unit configured to control transmission power in accordance with instruction of said control station.