Detection & discrimination of covert DS/SS signals using triple correlation

Abstract

In light of the growing use of direct sequence spread spectrum techniques and the increasingly congested communication environments, conventional linear and nonlinear intercept receivers are ineffective in detecting direct-sequence spread spectrum (DS/SS) signals if the transmissions are designed to be covert and the chip code sequences are unavailable. An investigation into using correlation-based processing is reported showing that the cyclostationary property of DS/SS provides detection capability. Results are given of a feasibility study into using the triple correlation function (TCF) for DS/SS detection taking into account the discrete polynomial structure of the chip code sequences involved. However, it is possible under certain conditions to detect and estimate the DS/SS length and its code generating function g(X).