KNN search-based trajectory cloaking against the Cell-ID tracking in cellular network

The widely used smartphone with powerful positioning capability makes it easy for a user to find his precise physical location. However, this may reveal a user's geo-location information, making the real-time tracking of the user possible. For example, on the basis of a sequence of numbers (i.e., Cell-IDs) received in the Cell-ID positioning, an entity can gain access to a person's movement routes without his consent. We argue that if the trajectory of a person is traced, then all his visits may be exposed. Therefore, trajectory cloaking against the mobile positioning is urgently necessary. In this paper, we propose a dummy base station replacement (DBSR) algorithm. It mainly uses the idea of dummy trajectory anonymity and is achieved by replacing the true Cell-ID provided by the network with a fake but nearby Cell-ID. We also implement our DBSR algorithm on an Android-based smartphone to evaluate its performance. Experimental results show that the DBSR algorithm can efficiently tackle the privacy breach caused by the single-base-station positioning in cellular network.