Digital signal transmission with cascaded heterogeneous chaotic systems - art. no. 016217

A new chaos based secure communication scheme is proposed to transmit digit al signals by combining the concepts of chaotic-switching and chaotic-modul ation approaches. In this scheme two heterogeneous chaotic circuits are use d both at the transmitter and receiver modules. First a binary message sign al is scrambled by two chaotic attractors produced by a set of chaotic syst ems (No. 1) of the drive module. The so produced small amplitude scrambled chaotic signal is further directly injected or modulated by different chaot ic system (No. 2) within the drive module. Then the chaotic signal generate d by this second chaotic system No. 2 is transmitted to the response module through the channel. An appropriate feedback loop is constructed in the re sponse module to achieve synchronization among the variables of the drive a nd response modules and the binary information signal is recovered by using the synchronization error followed by low-pass filtering and thresholding. Simulation results are reported in which the quality of the recovered sign al is higher and the encoding of the information signal is potentially secu re. The effect of perturbing factors like channel noise and nonidentity of parameters are also considered.