Patent ID: 7643845

Claim:
In radio transmitting and receiving of signals between a first communication device and a second communication device, a transmission power control method of controlling transmission power of the first communication device based on predetermined information supplied from the second communication device, the first communication device transmitting transmission power control information that is to be used in a transmission power control operation in the second communication device and is so determined that a reception signal quality of a signal transmitted from the second communication device and received by the first communication device approaches a target quality, the method comprising the steps of: determining whether the reception signal quality is smaller than a first threshold value, or the reception signal quality has become lower than a target quality by more than a second threshold value; and autonomously controlling the transmission power of the first communication device by increasing the transmission power in accordance with predetermined characteristics, regardless of the predetermined information supplied from the second communication device, when the reception signal quality is determined to be smaller than the first threshold, or have become lower than the target quality by more than the second threshold value in the quality determining step, the transmission power of the first communication device being increased from the transmission power value that is observed at the time of the determination.