Adversarial Obstruction of Millimeter Wave Links

We use a stochastic geometry approach to study an adversarial attack to the physical layer of millimeter wave communications, which is extremely vulnerable to blockage due to obstructions. Previous investigations have applied stochastic geometry to the study of millimeter wave communication scenarios with randomly located obstructions, but in this paper we investigate what happens if some of them are actually due to a malicious attacker. It turns out that, with just few strategically positioned obstructions, an adversary can significantly hinder the millimeter wave link operation and cause extremely high outage probabilities. As expected, scenarios with multiple reflections are more robust against this kind of attack, since they can exploit the diversity of reflected paths, despite their lower quality. Conversely, millimeter wave communications without (or with limited) multipath diversity are shown to be extremely fragile. We also investigate the impact on blockage of different parameters of the obstructions, including their number, shape, and size. Finally, we elaborate the applications of our findings to identify countermeasures against this attack.