Investigation of several demodulation schemes using adaptive filter in chaotic communication systems

Chaotic modulation is a vital spread spectrum approach in chaotic communications. It has recently been proposed for spread spectrum (SS) and code division multiple access (CDMA) communication. It first embeds the signal of transmission in the bifurcating parameter of a chaotic dynamical system. Then it uses the wide-band output of the chaotic system as the transmitted signal. In this paper, we have investigated the several demodulation schemes of chaotic communication using an adaptive filter. These demodulation schemes can reduce the effect of channel noise and also estimates the bifurcating parameter (i.e., the signal of transmission) sequentially which is required in a communication system. Three types of adaptive [filters: the least mean square (LMS) algorithm, the recursive least square (RLS) technique, Lyapunov adaptive filter (LAP) Seng Kah Phooi et al., (2002) are considered. It is found that the LAF demodulators based on the Lyapunov theory-based adaptive filtering can outperform the standard inversion approach, LMS and RLS demodulators.