Improved SLM Scheme for Reducing the PAPR of QAM OFDM Signals

Abstract

Since the orthogonal frequency division multiplexing (OFDM) symbol is a superposition of multiple independently subcarrier signals, it generates a large instantaneous power peak, which further leads to a large peak-to-average power ratio (PAPR). The original selective mapping (OSLM) was put forward to reduce PAPR, but its computational complexity is very high. Therefore, for solving this problem, we propose an improved SLM scheme for reducing the PAPR of quadrature amplitude modulation (QAM) OFDM signals. The proposed scheme uses PSK modulated signal sequence, orthogonal phase factor sets and deformation parameter sets to generate more OFDM signals with less inverse fast Fourier transform (IFFT) processors. Simulation results indicate that the proposed scheme not only can get a good PAPR performance, but can offer more savings for computational complexity.