Disclosed is a novel system and method for utilizing information gathered at a based station for tracking a trajectory of a mobile device. Three types of information may be used including radio-layer information, ID information, session based information, or a combination thereof. The information is gathered at cellular base-stations to localize a mobile device. Cell towers have wide penetration and extensive coverage, and base-stations/mobile-devices have access to a lot of information. In one example, a method for tracking mobile device locations at a based station begins with accessing a list of mobile device information previously collected from mobile devices communicatively coupled over the wireless communications network to the base station. Currently active mobile device information measured by the network elements is accessed. A trajectory of the mobile device communicatively coupled to the base station is estimated by mapping the list of information previously collected with the currently active mobile device information.