Research On The Peak-to-Average Power Ration Reduction And Adaptive Predistrotion In OFDM System

Firstly, the history and the application of OFDM technique, a promising wireless digital modulation technique of the next generation wireless communication,are presented in this paper. Then the concept and the key techniques of OFDM are discussed. One of the key techniques called the peak-to-average ration is briefly investigated and most of PAPR redunction techniques and linearization techniques in the literature are generalized. The effects of a nonlinear power amplifier without memory on OFDM system are also given.And then the principle of predistortion technique is analyzed.For the reduction of the distortion of the transmitter and the improvement of the power efficient, two different PAPR reduction structures are proposed. Which Peak Windowing aims directly at PAPR reduction of OFDM signal, While adaptive digital predistortion which is baed on look-up table puts its emphasis on the power amplifier linearization. Lastly an improved amethod of linearization technique called subsection linearization is introduced, then the combination of these two techiniques is also studied and some useful conclusions are achieved.