Patent ID: 8457246

Claim:
A transmitting end apparatus for amplifying a Transmit (Tx) signal according to an Envelope Tracking (ET) scheme in a wireless communication system, the apparatus comprising: an envelope gain controller for controlling a gain of a digital baseband Tx signal in accordance with power control; a detector for detecting an envelope signal from the digital baseband Tx signal whose gain is controlled, and for shaping the envelope signal; a first Digital to Analog Converter (DAC) for converting the shaped envelope signal into an analog envelope signal; and an envelope modulator for generating a drain bias of a power amplifier that amplifies a Radio Frequency (RF) Tx signal by using the analog envelope signal, wherein, if output power of the transmitting end apparatus is less than a threshold, the envelope modulator generates the drain bias of the power amplifier using a Direct Current (DC) signal, with a magnitude of the DC signal being determined based on the output power.