Deep neural networks have empowered accurate device-free human activity
recognition, which has wide applications. Deep models can extract robust
features from various sensors and generalize well even in challenging
situations such as data-insufficient cases. However, these systems could be
vulnerable to input perturbations, i.e. adversarial attacks. We empirically
demonstrate that both black-box Gaussian attacks and modern adversarial
white-box attacks can render their accuracies to plummet. In this paper, we
firstly point out that such phenomenon can bring severe safety hazards to
device-free sensing systems, and then propose a novel learning framework,
RobustSense, to defend common attacks. RobustSense aims to achieve consistent
predictions regardless of whether there exists an attack on its input or not,
alleviating the negative effect of distribution perturbation caused by
adversarial attacks. Extensive experiments demonstrate that our proposed method
can significantly enhance the model robustness of existing deep models,
overcoming possible attacks. The results validate that our method works well on
wireless human activity recognition and person identification systems. To the
best of our knowledge, this is the first work to investigate adversarial
attacks and further develop a novel defense framework for wireless human
activity recognition in mobile computing research