The purpose of the Power Amplifier is to boost the radio signal to a sufficient power level for transmission through the air interface from the transmitter to the receiver. It involves solving several contradicting requirements, which are such as linearity and efficiency. Unfortunately, these requirements tend to be mutually exclusive, so that any improvement in linearity is usually achieved at the expense of efficiency, and vice versa. In this book, the adaptive digital predistortion technique has been studied and compared with other techniques. The predistortion circuit inversely models the amplifier's gain and phase characteristics and, when combined with the amplifier, produces an overall system that is more linear and reduces the amplifier's distortion.