Multicarrier M-ary Permuted Quasi-Orthogonal Chaotic Vector Shift Keying with Index Modulation

Abstract

A novel multicarrier system based on chaotic sequences with permutation and index modulation to improve spectral efficiency is presented in this paper. In this design, the quasi-orthogonality property of the permuted versions of chaotic sequences is used for getting multiple reference signals, thereby reducing by the transmission overhead of reference chaotic signals over additional subcarriers. This helps in improving the spectral efficiency of the proposed system. Also, index modulation is applied to the permuted chaotic signals in all subcarriers to provide better efficiency in terms of spectrum utilization as well as energy consumption. Hence, the information bits are conveyed by both M-ary modulation symbols and the indices of the selected permutated signals. In addition, the analytical expressions for bit error rate (BER) of the proposed system over additive white gaussian noise (AWGN) is derived and simulation results are used to validate the analytical values. The performance of the proposed system is compared with the multicarrier chaotic system available in the literature, thereby proving that the proposed system outperforms the existing system with improved spectral efficiency and energy efficiency and also provides improvement in BER performance of about 2dB over AWGN channel with hardware complexity trade-off.