Hiding Cyclostationarity with Dispersive Filters for Covert Underwater Acoustic Communications

Cyclostationary features of communication signals can be considered as weaknesses from a security point of view. They can be used by eavesdroppers for signal detection, modulation recognition or blind parameter estimation. This work presents a simple approach to make the blind estimation or detection of these features more difficult. It relies on the use of a dispersive filter at transmission that acts as a secret key. This filter is a plugin that is applicable to any existing transmission scheme. Numerical results applied to a DSSS signal with channel replay simulations illustrate the benefits of the proposed method.