A Modified SLM Scheme With Low Complexity for PAPR Reduction of OFDM Systems

In this paper, we propose a new peak-to-average power ratio (PAPR) reduction scheme of orthogonal frequency division multiplexing (OFDM) system, called a modified selected mapping (SLM) scheme, which considerably reduces the computational complexity with keeping the similar PAPR reduction performance compared with the conventional SLM scheme. The proposed scheme is analytically and numerically evaluated for the OFDM system specified in the IEEE 802.16 standard. For the OFDM system with 2048 subcarriers, the proposed scheme with 4 binary phase sequences can reduce the complex multiplications by 63.5% with the similar PAPR reduction compared with the SLM scheme with 16 binary phase sequences.

I. Introduction

Recently, orthogonal frequency division multiplexing (OFDM) has been regarded and used as one of the core technologies for the communication systems. Especially, OFDM has been adopted for various wireless communication systems such as wireless local area networks (WLANs), wireless metropolitan area networks (WMANs), digital audio broadcasting (DAB), and digital video broadcasting (DVB). OFDM is an attractive technique for achieving high data rate in the wireless communication systems and it is robust to the frequency selective fading channel. However, an OFDM signal can have very high peak-to-average power ratio (PAPR) at the transmitter, which causes the signal distortion such as the in-band distortion and the out-of-band radiation due to the nonlinearity of high power amplifier (HPA), and induces the degradation of bit error rate (BER). Thus, the PAPR reduction is one of the most important research interests for the OFDM systems.