Agile broadband behavioral modelling of nonlinear power amplifiers using coarse-predistortion technique

This paper proposes a behavioral modelling method that allows the characterization of nonlinear power amplifiers over wide bandwidths of operation, for applications such as LTE-Advanced, while reducing the output observation bandwidth requirement. The proposed behavioral modelling system is based on the use of a coarse-predistortion function upstream of the device under test. This entails the identification of a coarse memoryless predistorter, independently, under narrowband testing condition. Then, the coarse-predistorter is used to cancel out the amplifier's static nonlinearities allowing for its characterization under reduced observation bandwidth. The proposed method is experimentally validated and the constructed model's performance is evaluated and compared against that of behavioral models identified using conventional behavioral modelling setup. Significant reduction in the required observation bandwidth is possible while maintaining the accuracy of the extracted models.