Doherty power amplifier linearization with augmented Hammerstein model for LTE systems

Abstract

In this paper, an augmented Hammerstein nonlinear model based digital pre-distortion (DPD) is utilized to linearize a Doherty power amplifier(DPA) for Long Term Evolution(LTE) system. The architecture of the augmented Hammerstein nonlinear model can be easily implement in Field Programmable Gate (FPGA). The model is composed of a look up table (LUT) and two finite impulse response (FIR) filters. Moreover, a digital predistortion platform is built to validate the effectiveness of the nonlinear model for linearizing the DPA for the LTE system. Based on the constructed platform, the accuracy of the augmented Hammerstein model is compared with those of memory polynomial (MP) model and LUT model by using a 90-W peak envelop power LDMOS field-effect-transistor Doherty power amplifier, which is driven by a LTE signal of 20MHz bandwidth and 10dB peak to average power ration (PAPR).