Parallel Amplitude and Phase Predistortion for RF Power Amplifier Linearization

This paper presents a novel technique for power amplifier linearization in digital microwave radio systems. The proposed technique is based on the use of a predistortion circuit, whose AM/AM and AM/PM responses are implemented separately as polynomial approximations of the respective responses of the ideal linearizer. The proposed scheme is shown to attain superior performance in comparison with other popular predistortion structures, such as those based on the cancellation of third or fifth order distortion, with no substantial aggravation in implementation complexity. The method lends easily itself to a digital adaptive implementation.