Direct Method in Determining the Direction of Action in the Coupling Map Ring

Recently, Hung and Hu provided a genuine way to carry binary data on a coupling map ring (CMR) for the chaotic communication (Phys. Rev. Lett., 101, 244102 (2008)). They use the temporal transfer entropy (TTE) to determine the direction of action, which tells bit 1 or 0, between two neighboring chaotic maps of the CMR. A direct method based on the correlation between the changes of two chaotic data is not only capable to resolve the carried bits but more effecient than the scheme of TTE.