Design and Performance Analysis of a New $M$ -Ary Differential Chaos Shift Keying With Index Modulation

A new M-ary differential chaos shift keying with index modulation (IM-MDCSK), which has the advantages of high data rate and low energy consumption, is proposed in this paper. In the proposed scheme, each data frame is divided into several time slots where the reference signal is placed in the first time slot and the rest time slots with specific indices are provided for information bearing signals. More exactly, the information bearing signals with active indices are modulated by M-ary DCSK symbols, and the active indices are determined by mapped bits via the combination number mapping method. At the receiver, the absolute values of decision variables in all branches are used to find the indices of active time slots, while M-ary DCSK demodulation is applied to recover the modulated bits. Moreover, we derive the analytical bit-error-rate (BER) expressions for the proposed scheme over additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels, and then simulation results verify our theoretical derivations. Finally, the performance of IM-MDCSK scheme is compared with M-ary DCSK and other up-to-date chaotic modulation schemes based on index modulation (IM). IM-MDCSK scheme is proved to be competitive and preeminent.