Correlation-Multi-Delay-Shift-Keying for Chaos Based Communications

In this paper, the new correlation-multi-delay-shift-keying (CMDSK) modulation scheme for chaos based communications is proposed. In this scheme the information-bearing time delayed chaotic sequence is subtracted with original one. As a result, the higher data rate is obtained by defining a different time delays in order to maps a multiple bits within a frame. The number of transmitted bits per symbol is proportional to the number of possible delayed sequences. The analytical expression for error rate, based on Gaussian approximation, is derived and the results are confirmed with Monte-Carlo simulation. The performance of the CMDSK are analyzed and compared with differential-chaos-shift-keying (DCSK) and correlation-delay-shift-keying (CDSK). The result shows that CMDSK scheme outperforms DCSK and CDSK scheme with the increase of spreading sequence M. Due to the larger number of delay lines and correlators at transmitter and the receiver, CMDSK requires higher hardware complexity.