| OFDM has been paid much attention to for its high spectrum efficiency and strong immunity to interference. It has been applied to many communication systems and become one of the candidates for the next generation mobile communication system. But high PAPR makes OFDM very sensitive to the nonlinearities of amplifier. To mitigate the nonlinearity distortions to OFDM signal and improve PA's efficiency, it is necessary to compensate the nonlinearities introduced by the amplifier. For this purpose, a lot of linearization methods have been investigated including back-off, feed-forward, feedback and pre-distortion. This paper explores adaptive pre-distortion based on LUT and polynomial in detail. Through computer simulation their performances is analyzed and compared; the results show their validity to compensate the nonlinearities of amplifier without memory. At last, pre-distortion of HPA with memory is mentioned and the tendency of the linearization development in the future is pointed out.
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