Preserving privacy while reducing power consumption and information loss in LBS and participatory sensing applications

Participatory sensing systems rely on the willingness of mobile users to participate in the collection and reporting of data using a variety of sensors either embedded or integrated in their cellular phones. Users agree to use their cellular phone resources to sense and transmit the data of interest because these data will be used to address a collective problem that otherwise would have been very difficult to solve. However, this new data collection paradigm has not been very successful yet mainly because of privacy concerns. Without adequate privacy-preserving mechanisms most users are not willing to participate. Although several schemes have been proposed in the literature, none of them offers a complete solution, and instead, trade offs exist. For example, anonymization-based schemes change the real location of the users, and therefore preserve their privacy, but they might not be precise enough for certain applications. On the other hand, encryption-based schemes, since they do not modify the real location of the user, are very accurate and serve well all applications; however, they are very costly in terms of energy consumption. In this paper we present a scheme that combines the good properties of both approaches to reduce the energy consumption of encryption-based schemes as well as the noise added by anonymization-based schemes. Our simulation results show that the proposed scheme in fact achieves the desired objectives of reducing the energy consumption and information loss while allowing the application to track the users accurately.