Research On New Digital Predistortion Technology Suitable For Dynamic Transmission System

With the development of mobile communication systems and the enhancement of awareness of green environmental protection,in the face of the upcoming 5G era,reducing power consumption of communication systems has become an urgent issue,and dynamic transmission(Dynamic Power Transmission,DPT)systems have become a research hotspot.At the same time,RF power amplifiers are an indispensable part of mobile communication systems with the highest power consumption.The contradiction between efficiency and linearity is becoming more and more serious.Therefore,research on the digital predistortion technology for power amplifiers suitable for dynamic transmission systems is urgently needed.This paper mainly studies the adaptive digital predistortion technology in DPT system based on improved direct learning structure.First,the nonlinear characteristics of power amplifiers,classic models and digital predistortion principles,and an improved Direct Learning Architecture(DLA)based on instantaneous complex gain are introduced.Then the power amplifier modeling effect of variable least power(Recursive Least Square,RLS)algorithm and least mean square algorithm(LMS)algorithm based on DLA structure at variable power input are studied respectively,and the causes of its errors are analyzed and proposed.A Normalized Least Mean Square(NLMS)algorithm based on DLA structure is presented.The simulation results show that the algorithm is more robust and can be applied to DPT systems.In order to further optimize the power amplifier linearization effect in the DPT system,two RLS-NLMS fusion algorithms based on RLS-NLMS combined algorithm,memory correction coefficient(MCC)and hill climbing algorithm are proposed,and their effectiveness is verified by simulation On the basis of this,the Fast Transversal Recursive Least Square(FTRLS)algorithm is introduced,and the FTRLS-MCC algorithm with high performance and low complexity is proposed.The simulation results show that the pre-distortion technology based on this algorithm is not only Can significantly optimize the linearity of the power amplifier of the DPT system,and the complexity of the algorithm is greatly reduced,which is beneficial to practical applications.Finally,based on the combination of software and hardware,a practical measurement scheme of a new digital predistortion technology for power amplifiers for DPT systems was constructed.