Privacy-Preserving Localization for Underwater Acoustic Sensor Networks: A Differential Privacy-Based Deep Learning Approach

Localization is a key premise for implementing the applications of underwater acoustic sensor networks (UASNs). However, the inhomogeneous medium and the open feature of underwater environment make it challenging to accomplish the above task. This paper studies the privacy-preserving localization issue of UASNs with consideration of direct and indirect data threats. To handle the direct data threat, a privacy-preserving localization protocol is designed for sensor nodes, where the mutual information is adopted to acquire the optimal noises added on anchor nodes. With the collected range information from anchor nodes, a ray tracing model is employed for sensor nodes to compensate the range bias caused by straight-line propagation. Then, a differential privacy (DP) based deep learning localization estimator is designed to calculate the positions of sensor nodes, and the perturbations are added to the forward propagation of deep learning framework, such that the indirect data leakage can be avoided. Besides that, the theory analyses including the Cramer-Rao Lower Bound (CRLB), the privacy budget and the complexity are provided. Main innovations of this paper include: 1) the mutual information-based localization protocol can acquire the optimal noise over the traditional noise-adding mechanisms; 2) the DP-based deep learning estimator can avoid the leakage of training data caused by overfitting in traditional deep learning-based solutions. Finally, simulation and experimental results are both conducted to verify the effectiveness of our approach.