Digital predistortion based on frequency domain estimation for OFDM systems with low complexity loop delay compensation

Abstract

Digital predistortion is an efficient and robust technique for improving the linearity of power amplifiers. In this paper, we propose a digital predistorter based on frequency domain for OFDM signals, which exhibits superior accuracy against the predistortion in time domain. Simulation results show that, the desired MER can be achieved with fractional delay error as large as 6% of sampling time. It is also shown that since in frequency domain a fractional delay translates to phase rotation, phase rotation estimation and compensation can be performed by a low complexity scheme. Comparison of implementation complexity in frequency domain against time domain illustrates an improvement of approximately 60%.