Joint Carrier-Code Index Modulation Aided $M$-Ary Differential Chaos Shift Keying System

A joint carrier-code index modulation aided M-ary differential chaos shift keying (JCCIM-MDCSK) system is proposed in this paper. In the proposed JCCIM-MDCSK system, the carrier and code indices are used to transmit extra carrier and code index bits, respectively. Moreover, the modulating bits are input to multiple M-ary DCSK modulators, and the resultant signals are transmitted by the selected spreading codes and loaded into the active carriers. The benefit of the joint carrier-code index modulation is fully exploited so that the data rate and bit-error-rate (BER) performance of the JCCIM-MDCSK system are enhanced in contrast to its competitors. In order to estimate the carrier and code index bits successfully, an effective joint carrier-code index detection algorithm is proposed for the JCCIM-MDCSK system. In addition, the theoretical BER expressions of the JCCIM-MDCSK system are derived over additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. Finally, the BER performance of the JCCIM-MDCSK system is compared to other state-of-the-art IM-based noncoherent chaotic communication systems. It is shown that the JCCIM-MDCSK system can achieve better BER performance than its competitors.