Concurrent PAR and power amplifier adaptation for power efficient operation of WiMAX OFDM transmitters

High peak-to-average ratio (PAR) of OFDM signals is a major bottleneck in the implementation of power efficient transmitters since the efficiency of a linear RF power amplifier reduce drastically due to backoff requirements. In this paper, a concurrent approach that uses adaptive baseband companding/ expanding of the OFDM signal along with dynamic PA biasing to achieve significant power savings in the transmitters is proposed. While using existing channel estimation techniques to drive the dynamic PAR adaptation, the proposed approach achieves a PAR reduction as high as 7.25 dB and power savings of 5.27X when channel conditions are good.