Design of Differentially Encoded-Differential Chaos Shift Keying system

In this paper, a new differentially coherent chaos-based communication scheme is proposed and named as Differentially Encoded-Differential Chaos Shift Keying (D-DCSK). The system utilizes the correlation relationship between chaotic segment and its shifted version. At the transmitter, transitions between successive bits are detected by XOR operation. Based on XOR output, the chaos source generates either a new segment or repeated copy of the previous segment. At the receiver, a reference bit is initialized, and each received segment is correlated with the previous over one bit duration. Correlation value is compared with a threshold and information bits are decoded by comparing threshold output with an updated reference bit. Bit-Error-Rate (BER) performance of D-DCSK is compared with conventional correlation delay shift keying (CDSK), and Chaotic ON-OFF keying (COOK) schemes in Additive White Gaussian Noise (AWGN) environment and with different values of spreading factors. In addition to the simplicity of the structure, results show that the proposed scheme outperforms other systems at higher values of the spreading factor.