Location privacy in sparse environment

Privacy of personal location information is becoming an increasingly important issue. This paper develops new methods for location privacy in sparse environment based on dummy users. The true user has been mixed with a set of dummy users in that LBSs can´t distinguish the true user so as to protect user location privacy. We present two techniques, the first one is called “dummy user trigger algorithm”, which is able to achieve the balance of user´s Location privacy and system performance, and the second one is named “dummy user generation algorithm” based on the period density matrix which enhances the truthfulness of dummy user.