Efficient and robust M-ary differential chaos shift keying scheme with code index modulation

作者：Tan, Yunsheng; Xu, Weikai^*; Hu, Wei; Wang, Lin

来源：IET Communications, 2019, 13(2): 232-242.

DOI：10.1049/iet-com.2018.5471

• chaos
• modulation
• Rayleigh channels
• fading channels
• chaotic communication
• spread spectrum communication
• error statistics
• differential phase shift keying
• ary differential chaos shift
• code index modulation
• chaos modulation scheme
• code-index modulation
• CIM-MDCSK scheme
• Walsh codes
• orthogonal chaos components
• candidate codes
• code indices
• ary DCSK signal
• theoretical symbol error rate
• bit error rate
• noise-reduction
• CIM-MDCSK outperforms DCSK
• frequency selective fading channel

In this study, a new chaos modulation scheme which combines M-ary differential chaos shift keying (DCSK) with code-index modulation (CIM-MDCSK) is proposed. In the CIM-MDCSK scheme, the two Walsh codes that are used to generate two orthogonal chaos components are selected from the candidate codes, whose code indices are determined by information symbols. Thus, the information bits are conveyed not only by M-ary DCSK signal but also by the indices of the Walsh codes. Theoretical symbol error rate (SER) and bit error rate (BER) of the proposed scheme are derived and confirmed by simulations. Furthermore, by applying the noise-reduction to reference signals of CIM-MDCSK, the SER/BER expressions are also derived. Simulation results show that the proposed CIM-MDCSK outperforms DCSK and M-ary DCSK based on Hilbert transform. Especially, the CIM-MDCSK with noise-reduction shows significant advantages. Moreover, the performance of CIM-MDCSK scheme is compared with direct sequences spread-spectrum system with code-index modulation over flat and frequency selective fading channel. The proposed CIM-MDCSK can offer good performance over frequency selective fading channel with a low complexity non-coherent receiver which does not require any channel state information and channel equalisation.

• 出版日期2019-1-18
• 单位厦门大学