Design and Performance Analysis of Differential Chaos Shift Keying System With Dual-Index Modulation

Abstract

In order to sufficiently utilize the time slot resources of the recently proposed pulse-position-modulation differential chaos shift keying (PPM-DCSK), we apply dual-index modulation to differential chaos shift keying and then present two differential chaos shift keying systems with dual-index modulation (DCSK-DIM), where the transmitted bits are partitioned into two orthogonal branches correspond to the in-phase branch and quadrature branch, respectively. Then, by means of the dual-index modulation technique, the mapped bits of in-phase and quadrature branches are modulated into a pair of distinguishable index symbols and thus recycle the time slot resources. At the receiver, two different detection methods are employed to determine the index symbols and demodulate the modulated bits carried by the active time slots. In addition, we derive the theoretical bit error rate (BER) expressions for the proposed DCSK-DIM systems over additive white Gaussian noise and multipath Rayleigh fading channels, respectively. In addition, then the simulation results validate the corresponding theoretical derivations. Finally, compared with other non-coherent chaotic communication systems, the proposed DCSK-DIM systems can achieve an excellent BER performance or data rate. Explicitly, the DCSK-DIM-I system makes a great progress in pursuit of admirable BER performance, while the DCSK-DIM-II system elevates the data rate to great extent.