Chaos based modulations from an information theory perspective

This paper investigates the information theoretic aspects of a class of chaos based modulations. In particular, the question about efficient channel utilization is considered. For the purpose of this paper, modulations based on chaos generated by iterated piecewise linear Markov maps are considered at the transmitter side and the optimal (Bayesian) detector on the receiver side. The paper shows that the symbolic sequence of the transmitter constitutes unexploited information that is transmitted on the channel. Consequently it reduces the channel capacity available to the payload (transmitted information bits). For simplicity, real valued differential chaos shift keying (DCSK) on a discrete time AWGN channel is considered as an example.