Cached SLM to reduce the PAPR of OFDM signal

Abstract

Selected mapping (SLM) is one of the most well-known peak-to-average power ratio (PAPR) reduction techniques proposed for the orthogonal frequency-division multiplexing (OFDM) systems. The main drawback of the conventional SLM scheme is high computational complexity because of numerous inverse fast fourier transform (IFFT) operations when transmitting one OFDM signal, which may hinder its wide application in certain systems. The aim of this paper is to propose a post-IFFT PAPR reduction scheme based on a cache structure. in the proposed scheme, several candidates are created through combining two of time-domain signal vectors in cache and the one with the lowest PAPR is transmitted. Because the generation of candidates is implemented after the IFFT, one OFDM signal only requires one complex IFFT operation when using the proposed cache scheme. simulation results show that the new proposed scheme has promising PAPR performance while it decreases the complexity compared with the conventional SLM scheme. In addition, the cache scheme has the ability to be combined with other scheme such as SLM to further reduce the PAPR at the cost of a moderate increase of the complexity. Copyright © 2012 John Wiley & Sons, Ltd.