A Multilevel Code Shifted Differential Chaos Shift Keying Scheme With Code Index Modulation

In this brief, a code index modulated multilevel code shifted differential chaos shift keying, which combines multilevel code shifted differential chaos shift keying (MCS-DCSK) with code index modulation, is proposed. In the proposed scheme, the reference chaos signal is the same with MCS-DCSK, and the multiple information bearing signals are simultaneously modulated by information symbols and selected Walsh codes with specified indices which are determined by additional information bits via the natural number to k-combination mapping method. The proposed scheme achieves higher spectrum efficiency compared to MCS-DCSK since additional bits are carried by code indexes. The analytical bit error rate of the proposed system is derived and confirmed by simulation. Finally, advantages of the proposed scheme over MCS-DCSK are verified by numerical results.