Performance Analysis of the Clipping Scheme with SLM Technique for PAPR Reduction of OFDM Signals in Fading Channels

Abstract

Since one of major problems of OFDM-based systems is high peak-to-average-power ratio (PAPR) of its transmitted signal, many PAPR reduction techniques and combined schemes with individual techniques have recently been developed. Among various techniques, the clipping technique has been widely used as a practical scheme owing to its low computational complexity and simplicity in implementation, while the selected mapping (SLM) technique is known to provide good PAPR reduction performance without signal distortion. Generally, the combined scheme of two PAPR reduction techniques, which are the clipping and the SLM, is expected to provide the enhanced performance of PAPR reduction, because the clipping noise of combined scheme would be less than that of single clipping technique, when the SLM technique is employed before clipping. However, the performance of clipping scheme with SLM technique has not been evaluated for practical systems over fading channels. In this paper, the performance of the clipping scheme with the SLM technique is theoretically analyzed and compared with simulation results over fading channels. The performance of combined scheme is analyzed with various clipping ratios, phase sets for SLM, and modulation schemes over flat and frequency selective fading channels. In addition, the effects of the clipping at the receiver and the oversampling on the BER performance are discussed. Based on the results of analysis, therefore, one can design the effective clipping scheme with the SLM technique for the PAPR reduction of OFDM-based systems.