Chaotic-pulse-position Modulation: An Improved third Party Intrusion Scheme using EKF

In a recent paper we have introduced a third party intrusion scheme to decode the transmitted message in CPPM using a Kalman Filter. In the present work, we improve the design of this intrusion scheme to not only allow us to recover the transmitted message but also enable the estimation of the signal power . This is a much more complicated task than the past one as the system model obtained becomes nonlinear. To achieve this goal, we have used a modified version of the EKF fed with a polynomial approximation. We have conducted experiments using the quadratic map and the logistic map. The outcome of these experiments shows that both the original message and the signal power can be effectively recovered. The BER performance of this scheme is compared to that of the CPPM for different SNRs.