Random Slope Coding for Jamming Attack Mitigation in FMCW Radars

This article investigates the adoption of random slope coding as a proactive technique against persistent smart jamming attacks in frequency-modulated continuous wave radars, a critical scenario for which standard interference mitigation techniques are ineffective. To this aim, both types of harmful effects caused by interference are considered, i.e., ghost targets and increased noise floor, which in turn depend on the level of slope coherence between the jammer's and victim radar's signals. We formulate a suitable optimization problem, whose analytical resolution unveils a simple strategy to maximize interference mitigation while guaranteeing a desired level of waveform unpredictability, providing a flexible way to tradeoff overall interference floor with ghost target rate. Four distinct cases are identified and analyzed, depending on concordance of slope signs and possible knowledge available to the jammer, framed within a probabilistic framework so as to account for uncertainty in both attack and defence policies. Numerical results show a superior overall performance tradeoff.