Physical-layer secrecy with chaotic DS/SS: unintended receiver performance analysis and system design

We study the physical-layer secrecy potential of a class of chaotic direct sequence spread spectrum (DS/SS) systems in additive white Gaussian noise, whereby a symbol stream is linearly modulated on a sequence generated by iterating an initial condition through a suitably chosen chaotic map. We present iteratively constructed sequences of chaotic DS/SS systems and develop methods for quantifying and comparing the uncoded probability of error (Pr(ϵ)) of unintended receivers that do not know the initial condition, against that of intended receivers. For a subclass of these systems, we show that the unintended receiver Pr(ϵ) decays as 1/ √ SNR, and develop metrics that accurately predict the relation between the unintended receiver Pr(ϵ) and system parameters.