Research On New Linearization Technology Of Power Amplifier

With the rapid development of wireless communication technology,various portable mobile communication terminals have been widely used.As one of the core components of the wireless communication system,the non-linear characteristics of power amplifier will cause distortion of the transmitted signal,thereby affecting the performance of the communication system.At the same time,modern wireless communication systems generally use nonconstant envelope modulation technology and multi-carrier transmission technology.These signals with higher peak-to-average ratio are more susceptible to nonlinear distortion of the power amplifier.Therefore,power amplifier linearization technology research is indispensable.Under the above background,the linearization technology of the power amplifier is studied,and the suppression of the nonlinear interference of the power amplifier at the transmitting end and the receiving end is realized.The main innovations are as follows:(1)For the transmitter,the digital predistortion technology is studied.The traditional LMS algorithm has slower convergence speed and lower convergence accuracy.In order to solve this problem,a LMS algorithm based on DE search is proposed.This algorithm uses the excellent optimization ability of the DE algorithm to accelerate the convergence speed of the LMS algorithm and improve its convergence,it can also solve the local convergence problem of DE algorithm.On this basis,a RLS algorithm based on DE search is proposed,which accelerates the convergence speed of the RLS algorithm and reduces the steady-state error.(2)Aiming at the receiver,a receiver multiple space linearization algorithm is proposed.First,the received signal is mapped into a high-dimensional space,and the nonlinear problem is converted into a linear problem.Then,the filter coefficients of the multi-dimensional linearization algorithm are solved.Finally,the estimated filter coefficients are used to weight the high-dimensional space signal.The simulation results show that the proposed multiple space linearization algorithm can effectively complete the suppression of nonlinear distortion.(3)On the basis of the above,the multiple space linearization algorithm is extended to broadband communication systems.Aiming at the memory effect problem caused by power amplifier in broadband communication system,a joint processing algorithm of multiple space linearization and nonlinear interference cancellation is proposed.The simulation results show that the proposed joint processing algorithm can well suppress the nonlinear distortion generated by the memory amplifier.