Privacy aware localization in VANET

Positioning or tracking in VANET is currently based on GPS. However, GPS is known to be prone to failure in case of emergencies. In addition, the current market penetration rate of GPS devices is low. Vehicles with built-in cellular communication capability are expected to be a part of the near future. Therefore, it is reasonable to assume that any vehicle possesses the functionality of a mobile unit (MU). The principal contribution of this paper is the proposed novel concept that employs the existing cellular RSS measurements as the basis for position estimation in VANET in situations where GPS services are unavailable. The proposed localization technique involves sampling the signal beacons received from three base stations surrounding the mobile unit for a very small time duration. Each of the RSS samples are then mapped to a sample of distance estimates based on shadowing radio propagation model. The medians of the generated distance sets are then used by a state of the art technique to produce a final location estimate. One of the important contributions of this work is justifying the selection of median over mean. An extremely small sampling duration negates the impact of mobile unit movement while the median selection neutralizes the deviation caused by time varying radio channel characteristics. All computation is restricted to mobile unit, thereby ensuring privacy. Simulation results demonstrate the efficiency of the proposed algorithm.