A new constellation mapping for PAPR reduction in OCDM without side information

As we move from 2G to 5G communication system, data rate increases. The two key enabling technologies for date rate increase are Multiple Input Multiple Output (MIMO) and Multi Carrier Modulation (MCM). Orthogonal Chirp Division Multiplexing (OCDM) is a newly proposed MCM technique. In OCDM, N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N$$\end{document} orthogonal chirps of same bandwidth are multiplexed. Being multicarrier transmission, like OFDM, OCDM also suffers from high Peak-to-Average Power Ratio (PAPR). A new Concentric Hexagonal Mapping with Iterative Substitution (CHM-IS) method has been proposed in this paper to reduce the PAPR of the OCDM signal. It has been shown that proposed scheme does not require to send any side information (SI) and also results in good PAPR reduction capability. We have evaluated the PAPR performance of OCDM system and also presented its comparison with existing Concentric Circle Mapping combined with Selected Mapping (CCM-SLM) and Multi-point Square Mapping combined with Selected Mapping (MSM-SLM) schemes. The SER analysis of the proposed scheme is carried out over AWGN channel and its performance is also evaluated over Rayleigh fading channels. We have also presented computational complexity analysis of the proposed scheme and its comparison with existing schemes. It has been shown that the proposed scheme provides a theoretical power gain of 1.76 dB and 2.22 dB w.r.t. CCM and MSM, respectively. CHM-IS provides almost same PAPR reduction but better SER performance compared to CCM-SLM and MSM-SLM. Moreover, computational complexity of CHM-IS is equal to CCM-SLM and MSM-SLM.