Multilevel code-shifted differential-chaos-shift-keying system

The M -ary differential-chaos-shift-keying (M -ary DCSK) system offers a good noise performance over an additive white Gaussian noise (AWGN) channel in the category of non-coherent detection chaotic systems. However, the way that the M -ary DCSK system utilizes the available Walsh codes results in a relatively low bandwidth efficiency. Moreover, the number of delay elements required at the transmitter and receiver increases exponentially with the number of bits per symbol. To overcome the aforementioned problems, we propose a Multilevel Code-Shifted Differential Chaos Shift Keying (MCS-DCSK) system in this paper. In the proposed MCS-DCSK system, the reference chaotic signal and the informationbearing chaotic signals are orthogonal and are transmitted in the same time slot. We show that the MCS-DCSK system significantly outperforms the M -ary DCSK system in terms of bandwidth efficiency and complexity. We also derive analytical BER expressions for the MCS-DCSK system over AWGN and multipath fading channels, and verify them with simulation results. Index Terms M -ary Differential-Chaos-Shift-Keying, Multilevel Code-Shifted Differential-Chaos-Shift-Keying (MCSDCSK), BER Expression, Bandwidth Efficiency.