Active tracking in mobile networks: An in-depth view

Tracking of mobile terminals in mobile networks is a technology with growing and diverse applicability. However, this task is non-trivial and might require either terminal or network adjustment and cooperation. Flexible, scalable, and cost-effective means of network-based tracking are highly desirable from the perspective of mobile operators. We present an in-depth overview of a particular method, the SMS-based active tracking, and demonstrate how this lean and non-intrusive approach is applicable to various existing architectures of mobile networks. We show the practicality of this approach by describing our academic proof-of-concept implementation, capable of tracking thousands of users periodically on the scale of minutes. We analyze the limits of active tracking, posed by the various network and terminal constraints (such as connection throughput, mobile network capacity or terminal battery lifetime) and conclude with discussion of its wide and long-term applicability.