Estimation of chaotic signals with applications in communications

In this paper we extend an estimation technique based on Viterbi algorithm for discrete-time chaotic signals immersed in noise. The proposed modification allows for orbits generated by maps with nonuniform invariant density to be estimated. This modified Viterbi algorithm is used in two digital modulation schemes: the Modified Maximum Likelihood Chaos Shift Keying using one and two maps. Both have better symbol error rate characteristics than non-coherent chaos communication schemes.