A simplified predistorter for compensation of nonlinear distortion in OFDM systems

This paper presents a new simplified predistortion scheme to compensate nonlinear distortion introduced by the high power amplifier (HPA) in OFDM systems. OFDM systems are susceptible to HPA nonlinearities in particular because of their large peak-to-average power ratios. Previously, a Volterra-based predistorter was suggested for compensation of HPA's nonlinear distortion in OFDM systems. In contrast to this earlier work, our adaptive predistorter in this paper utilizes a more simplified structure. It is shown that the new simplified structure exhibits faster convergence than the previous Volterra-based predistorter. In addition, the performance of the new predistortion scheme for OFDM systems is evaluated in terms of total degradation, optimal output backoff, and BER. Simulation results also show that our predistortion scheme is more efficient in compensating the nonlinear distortion of HPAs in OFDM systems than the previous scheme.