Patent ID: 7454226

Claim:
A communication terminal for exercising transmission power control to maintain the strength of a radio wave received by a base station at a certain level when wireless communication is to be established with the base station, the communication terminal comprising: a predicted transmission power value generation section for generating a predicted transmission power value, which corresponds to the power value to be transmitted through transmission power control; a detection value generation section for generating a detection value for the transmission signal to be output from an antenna; a gain mode selection section for selecting a high gain mode or a low gain mode; and a control section for comparing said predicted transmission power value and said detection value and halting a signal transmission operation if the difference between said predicted transmission power value and said detection value is not smaller than a predetermined value, wherein when the high gain mode is selected, the control section compares the predicted transmission power value with a first threshold value, and compares the detection value with a second threshold value, which is smaller than said first threshold value, and wherein when the low gain mode is selected, the control section compares the predicted transmission power value with a third threshold value, and compares the detection value with a fourth threshold value, which is greater than said third threshold value.