Chaos in Communications

Abstract

AbstractThis paper examines the roles in which chaos have been used in various approaches in communications. In the first approach, instead of modulating a periodic sinusoidal carrier as in conventional communications, various forms of modulation using an aperiodic chaotic waveform have been proposed. They include chaotic masking, dynamical feedback, chaotic switching, and different versions of chaos shift keying. Since these continuous‐time chaotic digital communication systems are modeled as stochastic nonlinear dynamical systems, the error probabilities of many of these systems do not have analytically tractable forms, but must be numerically evaluated using Ito/Stratonovich stochastic integrations. In the second approach, symbolic dynamics viewed as a “coarse‐grained” description of a chaotic dynamical system is exploited for modulating/coding of digital data. In the third approach, chaotic dynamics are viewed as analog channel encoders. In the fourth approach, communications using chaotic pulse‐position‐modulation are discussed. In the fifth approach, CDMA communication systems using spread sequences generated from chaotic dynamics are considered. Finally, in the sixth approach, the roles of chaos in laser communication and modeling of RF propagation effects for clutter and fading channel are discussed. Some comments are also provided on the practicality of various chaos‐based communication schemes.