On the predistortion technique for improving transmission linearity of OFDM system

Most existing research on linearization techniques for orthogonal frequency division multiplexing (OFDM) signal transmission assume that the power amplifier (PA) has memoryless nonlinearity. But the nonlinearity caused by peak to average power ratio (PAPR) in OFDM systems has memory effects. The Volterra series memory polynomial is the best way to model the nonlinearity. Since finding the inverse of the Volterra system is complicated, post-compensation schemes are more complex. In this paper instead of concentrating on post-compensation we propose a simple adaptive predistorter scheme to compensate for the nonlinearity of the PA. The performance of the proposed predistorter scheme is compared with the non-compensated signal in terms of the symbol error rate (SER) and the spectral regrowth.