CLAP: A Contract-based Incentive Mechanism for Cooperative Localization Balancing Localization Accuracy and Location Privacy

In cooperative localization, the sharing of location information has raised the risk of privacy breach. Geo-indistinguishability, as a formal notion of location privacy, can protect the user’s location privacy by adding random noise into his true location, while it degrades the localization accuracy inevitably. This paper considers the tradeoff between the cooperative nodes’ privacy preservation level and the target’s localization accuracy. Since it incurs privacy cost for the cooperative nodes to report their location information, an incentive mechanism for the cooperative nodes to contribute their data is necessary. In this paper, we propose a feasible incentive mechanism, named CLAP, based on contract theory to reward the cooperative nodes and ensure the expected localization accuracy. Specifically, we establish an optimization problem of minimizing the payment from the target, while guaranteeing the expected localization accuracy. By simplifying the constraints and transforming the original problem into a convex optimization problem, a closed-form solution is given. Extensive simulations evaluate the performance and validate the feasibility of our proposed contract-based incentive mechanism.