A low complexity pre‐distortion scheme for power amplifier linearization in wideband applications

Abstract

In this paper, a nonlinear autoregressive with exogenous inputs (NARX) digital pre-distortion scheme to linearize power amplifiers is proposed. The proposed NARX digital pre-distortion gives better accuracy and spectral leakage suppression compared with other commonly used Volterra-based techniques. The stability criterion of the NARX digital pre-distortion is derived from the frequency domain analysis. Simulation is carried out with a 20 MHz single carrier long-term evolution signal and two-carrier long-term evolution signal and instantaneous to average ratio of 6.2 dB at 0.01% complementary cumulative distribution function (CCDF). The results of simulation analysis show a slight improvement in adjacent channel leakage ratio performance with 30% reduction in the number of floating point operations compared with conventional predistortion techniques.NMSE, normalized mean square error; MP, memory polynomial; GMP, generalized memory polynomial; NARX DPD, nonlinear autoregressive exogenous digital pre-distortion; LTE, long-term evolution. 8 of 12 P. VARAHRAM ET AL.