Design of an initial condition‐index chaos shift keying modulation

Abstract

An initial condition index chaos shift keying modulation is proposed. This design aims to increase the spectral and energy efficiencies to unprecedented levels. The proposed scheme exploits the initial conditions to generate different chaotic sequences to convey extra bits per transmission. In the proposed design, the input data stream is formed in blocks of $p_{; ; \rm tot}; ; =n + 1$ bits. In this architecture, $n$ bits are mapped into $N=2^n$ predetermined initial conditions that are used to generate unique chaotic sequences at the transmitter. At the receiver side, the predetermined initial conditions are used to generate a set of $N$ chaotic sequences that are correlated with the received signal. The index of the initial condition for which the chaotic sequence produces a maximum correlation with the received signal is selected to recover the mapped bits, and the corresponding sequence is used to despread the transmitted modulated bit. To validate the proposed scheme, the bit error rate over fading channels is analyzed and formulated and the proposed system performance is compared with other conventional and index modulation schemes. In comparison to rival modulation schemes, the results obtained in the proposed work show a competitive performance.