Previous works withM-ary differential chaos shift keying (MDCSK) schemes are designed for resisting the impulsive noise of power line communication (PLC). However, real PLC channel environments are complex, existing schemes primarily address impulsive noise but do not effectively reflect the advantages of the system in a real PLC environment. This paper first discusses the bit-error-rate (BER) performance of the MDCSK system in Katayama PLC environments, and designs a derivation scheme of time slots-dependent BER. Then, based on the characteristics of periodic changes in the Katayama PLC channel environment, an adaptive-MDCSK (AD-MDCSK) is proposed to obtain better BER performance in such environments, which eliminates the need for a device to pre-check the BER. In the proposed scheme, the two types of MDCSK schemes are switched with the time slots period changing, where two categories of detectors are also changed correspondingly at the receiver. The BER of the AD-MDCSK is derived and analyzed regarding its effectiveness over Katayama PLC channel. The simulation results verify the accuracy of the design and show the superior performance of the proposed scheme. The BER performances of the proposed system are compared to other existing schemes, demonstrating its better BER performance.

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.