Research On The Peak-to-Average Power Ratio Reduction And Adaptive Predistortion In OFDM System

Firstly, the concept and the computation of Peak-to-Average Power Ratio (PAPR) in OFDM system are briefly discussed. Then the statistical properties of PAPR are analyzed, and most of PAPR reduction techniques in the literature are generalized. At the same time, the effects of a nonlinear power amplifier on the system performance are presented, and several familiar models of the nonlinear amplifier without memory are given. The principle of the adaptive digital predistortion and the comparison of two mainstream techniques'performance are also introduced and given.On the basis of theoretic analysis, two different PAPR reduction structures are proposed, which are Peak Windowing and adaptive predistortion. Peak Windowing aims directly at the PAPR reduction of OFDM signal, while adaptive digital predistortion method which is based on look-up tables puts its emphasis on the power amplifier linearization. The performances of these algorithms are evaluated for OFDM system, and some useful conclusions are achieved.