Effect of Clipping and Filtering with Distortionless PAPR Reduction for OFDM Systems

Recently, orthogonal frequency-division multiplexing (OFDM) is adopted by various wireless communications standards, but its high peak-to-average power ratio (PAPR) nature significantly degrades the power amplifier (PA) efficiency. To address this problem, various PAPR reduction schemes have been proposed in the literature, and clipping and filtering (CAF) has been considered as the simplest method while it imposes severe nonlinear in-band distortion. In contrast, selected mapping (SLM) and trellis shaping (TS) have been recognized as well- studied distortionless PAPR reduction methods. In this paper, we investigate the application of such distortionless PAPR reduction techniques prior to the OFDM systems with CAF in order to alleviate the resulting in-band distortion. Our simulation results demonstrate that the additional PAPR reduction based on SLM or TS will help improving the performance in terms of PAPR reduction capability, PA efficiency, and the resulting system level performance for a given amount of out-of-band power radiation.