WCDMA outphasing power amplifier with a software defined transmitter/receiver architecture for determination of the predistortion function

摘要

A flexible and easily configurablesoftware defined transmitter/receiver (TX/RX) architecture is described,which allows the determination of the distorted complex transfercharacteristics of a 3 port nonlinear outphasing power amplifier (PA) forapplication in a WCDMA base station. The TX/RX architecture is capable ofgenerating high precision single sideband signals (SSB) using a DSPalgorithm, which is almost insensitive to measurement errors and to thefrequency response of the output measurement channel. Based on this aninverse predistortion function for a necessary linearization is calculatedand implemented into a FPGA (field programmable gate array) throughlook-up-tables (LUT). The common base band and the differential phase anglesare predistorted, resulting in a linearization of the PA.