Reference-shifted DCSK modulation scheme for secure communication

To increase the attainable data rate of differential chaos shift keying (DCSK), reference-shifted differential chaos shift keying (RS-DCSK) modulation scheme is proposed in this paper. By using both the exact replica and the shifted version of every chaotic reference sample in DCSK as message bearers, two bits of data can be carried in one data-modulated sample sequence., Theoretical analysis and simulation results show that RS-DCSK could achieve doubled attainable data rate (bandwidth efficiency), featureless frequency spectrum, greatly increased communication security and even better bit error rate (BER) performance in comparison to DCSK.