A Technique to Reduce PAPR for OFDM-IM Using Multiple Mapping Rules for IM

Abstract

Orthogonal frequency division multiplexing (OFDM) with index modulation (IM) (or OFDM-IM) has attracted increasing attention due to its high spectral efficiency as well as high energy efficiency for next generation wireless communication systems. Despite its advantages over OFDM, it also inherits drawbacks of OFDM, e.g., a high peak-to-average power ratio (PAPR) problem. In this paper, we propose a novel PAPR reduction method for OFDM-IM by exploiting the availability of multiple mapping rules for IM. While the proposed approach is similar to the selected mapping (SLM) scheme for conventional OFDM, the main difference is that it is based on multiple mapping rules that are naturally given for IM (thus, this method is not applicable to OFDM). Furthermore, in order to avoid the transmission of side information (of the used mapping rules), a blind search detector that combines a blind search method and a low-complexity maximum likelihood (ML) detector is proposed. From the simulation results, we can observe that the proposed PAPR reduction method for OFDM-IM has a lower computational complexity than that of the SLM method for conventional OFDM, while providing similar or slightly better performances in terms of bit error rate (BER) and PAPR reduction.