A modified SLM scheme with two-stage scrambling for PAPR reduction in OFDM systems

Abstract

This paper proposes a modified selective mapping (SLM) technique to improve the high computational complexity required for the SLM technique in the orthogonal frequency division multiplexing (OFDM) system, and it can be regarded as a suboptimal SLM technique for peak to average power ratio (PAPR) reduction. The proposed method which generates W candidate signals is through the phase factor to carry out the first phase scrambling for the input signal to produce W/2 signals, followed by the inverse fast Fourier transform (IFFT) and then the second phase scrambling to produce the remaining W/2 signals. The generation mechanism of the phase factor is mainly based on the sub-code of the Reed-Muller codes with random ordering. The simulation results show that adopting the proposed method results in the improved performance of PAPR that are suboptimal compared to adopting the SLM technique but it simplifies the number of adders and multipliers required by the traditional SLM technique.