Patent ID: 8201040

Claim:
A communication device comprising: a receiver that continuously receives a plurality of data pieces from a transmitter via a radio link signal; an instruction transmitter that periodically, at a first predetermined time interval that is shorter than a second time interval at which the transmitter transmits the plurality of data pieces, transmits, to the transmitter, an instruction controlling a transmission power of the radio link signal based on a comparison between a target receiving quality of the radio link signal and a measured receiving quality of the radio link signal; a setting unit that sets the target receiving quality of the radio link signal; a determining unit that determines whether any one of the plurality of data pieces is lost; a retransmission request unit that transmits a retransmission request to the transmitter requesting retransmission of a lost piece of the plurality of data pieces data when, or immediately after, loss of the lost piece of the plurality of data pieces is determined, wherein the instruction transmitter transmits an instruction instructing the transmitter to increase the transmission power of the radio link signal when the measured receiving quality is lower than the target receiving quality, the setting unit increases the target receiving quality by a predetermined value after sending the retransmission request, when transmitting the retransmission request, or immediately after loss of the lost piece of the plurality of data pieces is determined, and the setting unit decreases the target receiving quality by the predetermined value after a lapse of a predetermined time period from increasing the target receiving quality when, or immediately after, loss of the lost piece of the plurality of data pieces is determined.