Linearization Of Power Amplifier Based On Digital Predistortion Technology

As the power amplifier(PA) is inherently nonlinear in Wireless CommunicationSystem,the spectral growth out of the signal bandwidth and the signal distortion limitthe efficiency of PA and spectrum utilization.This paper,based on analyzing theprinciple of the nonlinearity of PA,firstly discusses the modeling methods ofmemoryless and memory PA,and studies the digital predistortion techniques mainly.Tomemoryless PA’s linearization,the paper uses two digital predistortion methods,whichare based on LUT(Look-Up Table) and polynomial algorithm without memory,andpresents a new method based on an improved LMS adaptive algorithm with variablestep-size.To memory PA’s linearization,the paper adopts another two digitalpredistortion methods of LUT and polynomial algorithm with memory,and proposes anew method based on an improved LMS-RLS adaptive algorithm.After the simulationof the methods above in the Matlab environment,the results show that,the linearity ofPA is improved,and the effect of the new mothods are greater than the originalalgorithm,and reduce the ACI and signal distortion greatly.