A low- complexity precoding technique for PAPR reduction of OFDM signals

The high peak- to- average power ration PwPR in one the main problems of an orthon-onalfrequncy division multiplexing OFDM system. As a result of the high PAPR, the hardware complexity of the high power amplifier HPA is increased. Because, during the passing via a non- linear HPA the OFDM signal is clipped. In present study, we investigate the performance of complex vandrmonde matrix transform CVMT in a pre-coding the performance of system to reduce the high PAPR .we show that the serial com-bination of two CVMT and inverse FFT IFFT matrices eliminates the impact of each other when their dimensions are the same. In this case, a sparse matrix is achieved by the multiplication of two CVMT and LFFT matrices The obtained matrix has only one non – zero element in each row and column and hence the PAPR of the OFDM sig-nals is remarkably reduced. The CVMT pre-coding approach is combined with low complexity interleaving method to make a compromise between the PAPR reduction and implementation complexity. The valuable reults are achiened for 16-QAM matix tansform WHMT. And discrete cosine matrix transform DCMT approaches.