A New Scheme to Mitigate the OFDM High PAR Problem by Minimizing the Signal´s Nonlinear Distortion Caused by HPA

How to mitigate the negative impact of high PAR in OFDM systems is an important issue. Most of recent works have focused on minimizing the PAR of OFDM signal to enhance performance. However, after relating this issue with the specific characteristics of HPA, we propose a new scheme to mitigate the high PAR problem. Rather than minimizing OFDM signal´s PAR, the new scheme uses the amount of OFDM signal´s nonlinear distortion to be caused by HPA as a new measure and increases the performance of OFDM system by minimizing this nonlinear distortion. The pre-calculation of the new measure is achieved by employing an adaptive nonlinear system identification process. Meanwhile, because the new scheme only changes the measure of the OFDM signal but not the frameworks of the prior PAR-reduction methods based on minimum PAR criterion, these prior PAR-reduction methods can be easily extended to incorporate the new scheme. A case study of the new scheme by adopting it in the SLM method shows its superiority over the conventional scheme