A demand-aware location privacy protection scheme in continuous location-based services

Location-based Services (LBSs) via mobile handled devices have been subject to major privacy concerns for users. Currently, most of the existing works concerning the continuous LBS queries mainly focus on users´ privacy demands with little consideration of the service of quality (QoS). In this paper, we propose a Demand-Aware Location Protection scheme (DALP) for continuous LBS requests, allowing a user to customize not only location privacy but also QoS requirement. However, this results in that the privacy and QoS requirement cannot be met together in considerable query points and the location privacy protection cannot be provided for the continuous LBS queries. We point out its underlying reason is that in few LBS query regions the footprints are sparse or the privacy requirements are set unreasonably high. Therefore, a maximum Demands-Aware Query Sequence algorithm (MaxDAQS) is proposed in the scheme. Through identifying and restraining the queries in those regions, most of LBS queries are satisfied, thus, the longest LBS query sequence is obtained which can satisfy a user´s specific privacy and QoS requirements simultaneously. The extensive simulations on a large dataset prove the effectiveness of our approach under various location privacy and QoS demands.