Adaptive digital techniques for efficiency and linearity enhancement of CMOS RF power amplifiers

Abstract

This paper presents a baseband adaptive digital compensation technique for cost-effective CMOS integration of next-generation OFDM wireless transmitters. High power efficiency and linearity are simultaneously achieved by using a class-B power amplifier (PA) with less back-off and treating the memoryless AM-AM and AM-PM distortions in the digital domain. When a 64-QAM OFDM signal is transmitted, computer simulations indicate that the post-compensation ACPR and EVM are improved by 13 dB and 30 dB, respectively. The average power efficiency of the PA is 10.9% as opposed to 3.2% of a class-A counterpart for typical usage patterns.