New Construction Scheme to Reduce the PAPR of M-QAM OFDM Signal

A novel time domain combination scheme is proposed to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. in this paper, a high-order quadrature amplitude modulation (QAM) OFDM signal sequence is constructed with several Quaternary/Binary phase shift Keying (QPSK/BPSK) signal sequences. As this operation can be implemented after the inverse fast fourier transform (IFFT), more candidates can be accommodated by the proposed scheme with fewer numbers of IFFT operations. Although for the same number of candidates, the PAPR performance of our proposed scheme is slightly lower than the conventional selected mapping (C-SLM), our scheme significantly decreases the computational complexity. Simulation results also show that the proposed scheme almost achieves the same bit error rate of the C-SLM when they pass through the nonlinear high power amplifier.