Adaptive methods for chaotic communication systems

We describe several existing and two new nonlinear dynamics (NLD)-based communication schemes, addressing the shortcomings and advantages of each. One new method is based on modulating the parameters of one or more chaotic generating systems with the signal(s) of interest. The output of the resulting nonstationary chaotic system is transmitted across the channel, and the signals are extracted via a continuous adaptation of system coefficients. The other novel method involves injecting the signal of interest as dynamic or feedback noise into the chaotic generating system. The noisy output is transmitted, and the dynamics of the generating system are estimated at the receiver. These dynamics are used to generate short term prediction errors, which are proportional to the original dynamic noise if the recovered system coefficients are reasonably accurate. Both methods have particular application to radio frequency (rf) communications, where spectral noise and frequency selective fading of signal power are real problems.