Design and Analysis of a New Index-Modulation-Aided DCSK System With Frequency-and-Time Resources

We propose a new index-modulation-aided differential chaos shift keying (DCSK) system using frequency-and-time resources, referred to as CTIM-DCSK system, to achieve high-data-rate transmissions. In the proposed system, the orthogonal sinusoidal carriers are used to transmit both the reference-chaotic and the information-bearing signals. Moreover, the frequency-and-time resources are considered as indices to carry additional information bits. To simultaneously boost the bit error rate (BER) performance and reduce the system complexity, this paper proposes a new CTIM-DCSK signal based on the frequency-and-time resources, in which the time slots used by the selected subcarriers convey the same index bits. We employ a noise-reduction method at the receiver to further improve the BER performance of the proposed CTIM-DCSK system. We also derive the theoretical BER expressions of the CTIM-DCSK system over two different channels, i.e., additive white Gaussian noise (AWGN) channel and multipath Rayleigh fading channel. We analyze the data rate, complexity and spectral efficiency of the CTIM-DCSK system in comparison with the state-of-the-art counterparts. Analytical and simulation results verify the accuracy of the theoretical analysis and the advantage of the proposed CTIM-DCSK system. Consequently, the proposed CTIM-DCSK system appears to be a competitive candidate for low-complexity Internet-of-Things applications.

Automated summary

We propose a new index-modulation-aided differential chaos shift keying (DCSK) system, the CTIM-DCSK system, that utilizes frequency and time resources for high-data-rate transmissions. The system uses orthogonal sinusoidal carriers to transmit reference-chaotic and information-bearing signals, while the frequency and time resources are used as indices for additional information bits. The proposed CTIM-DCSK system improves bit error rate (BER) performance and complexity reduction by using time slots to convey the same index bits. Noise reduction methods at the receiver further enhance BER performance. The theoretical BER expressions are derived and compared with existing counterparts, confirming the accuracy and advantage of the proposed CTIM-DCSK system. Therefore, it is a competitive candidate for low-complexity Internet-of-Things applications.