Research On Baseband Predistortion In OFDM System

OFDM has been paid more attention to due to its high spectrum efficiency and robust capability in interference resistance. It has been successfully used in many communication systems and become one of the candidates for the next generation mobile communication system. But high PAR makes OFDM very sensitive to the nonlinearities of amplifier. To mitigate the nonlinear distortions to OFDM signals and improve HPA's efficiency, it is necessary to compensate the nonlinearities introduced by the amplifier. So a lot of linearization methods have been investigated including back-off, feed-forward, feedback, LINC and predistortion method. In this paper we focus on the baseband predistortion technique in OFDM system. Based on the LUT predistortion method, we separately proposed new methods for both memoryless HPA and memory HPA, through analysising and summarizing many kinds of current predistortion methods. Computer simulation results show that these methods have perfect performances and are suitable for project implementation.