Patent ID: 7197286

Claim:
A radio comprising: a power amplifier for amplifying a signal to be transmitted; a distortion compensator for compensating a distortion of the power amplifier, said distortion compensator having a distortion compensation coefficient update part for updating distortion compensation coefficients based on a difference between a transmission input signal input to the power amplifier and a feedback signal of a transmission output signal output from the power amplifier, a memory part for storing said distortion compensation coefficients, and a distortion compensation coefficient multiplier for reading out the distortion compensation coefficient from said memory part according to a level of a transmission input signal and multiplying said transmission input signal by said distortion compensation coefficient; and a bias voltage controller for determining a bias voltage of the power amplifier based on the level of the transmission input signal or a transmit power control signal so as to substantially maximize power efficiency of the power amplifier over a whole operational area thereof while meeting a specification as to an Adjacent Channel Leakage power Ratio (ACLR).