Design and performance analysis of generalised carrier index M-ary differential chaos shift keying modulation

In this study, two generalised carrier index M-ary differential chaos shift keying (CI-MDCSK) schemes are proposed, which combine index modulation with multicarrier M-ary DCSK (MC-MDCSK). At the transmitter, two different index selectors based on two different mapping rulers are employed to select active carriers, where the modulated bits are transmitted by the active carriers through M-ary DCSK modulation, which is based on the Hilbert transform and constellation theory. At receiver, maximum or minimum energy detection is employed to determine the active carriers, where the bits carried on these active carriers are demodulated. The analytical bit error rate (BER) expressions over additive white Gaussian noise as well as multipath Rayleigh fading channels are derived. Simulations are performed with different numbers of carriers and different constellation sizes. Both analytical and simulation results show the superiority of the new schemes in BER performance or spectral efficiency (SE) compared with the MC-MDCSK scheme. Moreover, compared with conventional DCSK, CI-MDCSK schemes owns both better BER performance and SE in some cases, where the constellation is not greater than 8.