Patent ID: 8738065

Claim:
A radio communication system in which a small cell base station forming a small cell smaller than a large cell formed by a large cell base station is installed within the large cell and a large cell radio terminal is connected to the large cell base station, wherein a network device formed of at least one of the large cell base station and a an upper level device of the large cell base station comprises: a ratio acquisition unit configured to acquire a ratio of an amount of interference that the large cell radio terminal receives from the small cell base station to a first amount of interference being regarded as a total amount of interference that the large cell radio terminal receives, wherein the amount of interference that the large cell radio terminal receives from the small cell base station includes a field intensity at which the large cell radio terminal receives a reference signal from the small cell base station, wherein the ratio acquisition unit calculates the first amount of interference by using a field intensity at which the large cell radio terminal receives a reference signal from the small cell base station, a field intensity at which the large cell radio terminal receives a reference signal from a large cell base station different from the large cell base station to which the large cell radio terminal is connected; and an instruction unit configured to instruct the small cell base station to control transmission power of a small cell downlink being a downlink in the small cell base station, based on the ratio acquired by the ratio acquisition unit.