Differential Pulse-Position Modulation for Multi-User Chaotic Communication

• Published in: IEEE transactions on vehicular technology Vol. 73; no. 8; pp. 11303 - 11317
• Main Authors: Wu, Linhuang, Yin, Xiangxiang, Chen, Haoyu, Chen, Pingping, Fang, Yi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Channels; Chaotic communication; Codes; differential chaos shift keying (DCSK); Indexes; Modulation; multi-access; Pulse position modulation; pulse position modulation(PPM); Redesign; Symbols; Transmitters; Ultrawideband; walsh code (WC); Wireless communication
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2024.3373036

In this paper, we valign="-60pt propose a joint differential pulse position modulation and differential chaos shift key modulation (DPPM-DCSK), where one bit modulates the reference PPM signal by chaotic signal, and the other <inline-formula><tex-math notation="LaTeX">m_{c}</tex-math></inline-formula> bits are mapped by the position index of this chaotic pulse in the information signal. In particular, in the DPPM-DCSK, the information-carrying PPM signal for the current symbol also serves as the reference for the next symbol. It can avoid the energy and rate wastes in the conventional PPM-DCSK. Moreover, we redesign the differential Walsh codes (WC) for DPPM-DCSK to enable multi-user communications. The numerical bit-error-rate (BER) performance of the proposed DPPM-DCSK-WC over multipath Rayleigh fading channels are derived and then verified by simulations. The results demonstrate that the DPPM-DCSK-WC can achieve performance gains of more than 2 dB over the conventional PPM-DCSK and DDCSK-WC for multi-user scenarios, and this gain can be up to 5 dB in the high-delay channels at a BER of <inline-formula><tex-math notation="LaTeX">{{10}^{-4}}</tex-math></inline-formula>. In addition, the superior performance of the proposed scheme is proved over ultra-wideband (UWB) wireless channels, which indicates its great potential for chaotic-based wireless applications.