A high-reliability dual-mode M-ary differential chaos shift keying system with index modulation

Abstract

This paper introduces a novel high-efficiency dual-mode multi-carrier differential chaos shift keying (HRDM-MDCSK-IM) system that integrates index modulation and noise suppression techniques. The system utilizes distinct modulation schemes for active and inactive time slots on each subcarrier and encodes them using reference selection indexing and combined Walsh code indexing, thereby enhancing the system's efficiency. At the receiver's end, the system employs the sliding average of reference signals to reduce noise and performs secondary noise reduction on information signals during active time slots to recover information bits. This approach optimizes the bit error rate (BER) performance and improves the overall system performance. Simulation results demonstrate that the HRDM-MDCSK-IM system significantly outperforms existing benchmark systems in terms of data rates and spectral efficiency. The paper also derives the theoretical expressions for the BER of the system under both additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels, and verifies their accuracy through simulation. The theoretical analysis, coupled with simulation results, confirms the superior performance of the HRDM-MDCSK-IM system and highlights its potential for practical applications in high-efficiency wireless communication systems.