A game theoretic approach for collaborative caching techniques in privacy preserving location-based services

The number of users who use location-based services (LBS) is increasing rapidly along with the proliferation of mobile devices such as the smartphone. However, LBS users have concerned about their privacy because the collected individual location information can pose a privacy violation. Therefore, it is no wonder that a lot of research is being conducted on topic such as location k-anonymity and pseudonym to prevent privacy threats. However, existing research has several limitations when applied to real world applications. In this paper, we propose a novel architecture to preserve the location privacy in LBS using the Virtual Individual Server (VIS) to overcome drawbacks in existing techniques. We also introduce the collaborative caching technique which shares extra query results among users to mitigate privacy/performance tradeoffs. Game theory is used to overcome the free rider problem that can occur during the sharing process. Simulation results show that the proposed technique achieves sufficient privacy protection and reduces system performance degradation.