Duplicate Suppression for Efficient Floating Car Data Collection in Heterogeneous LTE-DSRC Vehicular Networks

in Computer Communications (2018), 123

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of ... [more ▼]

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of applications. Vehicular Floating Car Data (FCD) collection is a major representative of this paradigm. Massive data collection from floating vehicles is the key to Intelligent Transportation Systems. We address the design and performance evaluation of a data collection protocol for the use case of periodic data collection. We target robustness, optimizing the amount of data and the value of the collection period, keeping in mind the goals of autonomous node operation and minimal coordination effort. From a system point of view, we believe that best solutions should jointly exploit the Long Term Evolution (LTE) cellular access network and the Dedicated Short-Range Communication (DSRC) based Vehicular Ad Hoc Network (VANET). Through a detailed comparative analysis, we show that such a hybrid approach offers superior performance, especially as for offloading the cellular radio access. A lightweight signaling procedure is designed, based on the DSRC VANET, which is able to avoid most of the duplicated data records, even if a distributed operation approach is pursued. The impact of the proposed protocol on the VANET load is evaluated and proved to be quite small, so that it does not interfere with other VANET-specific messages. [less ▲]

AnonPubSub: Anonymous publish-subscribe overlays

in Computer Communications (2016), 76

On Evaluation of Location Privacy Preserving Schemes for VANET Safety Applications

in Computer Communications (2015), 63(1), 11--23

Location privacy in vehicular ad hoc networks has gained considerable attention in the past few years. The majority of studies concern changing pseudonyms to prevent linking messages of the same pseudonym ... [more ▼]

Location privacy in vehicular ad hoc networks has gained considerable attention in the past few years. The majority of studies concern changing pseudonyms to prevent linking messages of the same pseudonym. However, the precise spatiotemporal information included in beacons (i.e., timestamp, position, speed and heading) makes them vulnerable to tracking even if they are completely anonymous. One of the most important issues in designing location privacy scheme is to preserve the quality of service of the application. This issue is more significant for safety applications, since they require precise and frequent state updates. Thus, it is crucial to consider this trade-off between location privacy and quality of service of the safety application when designing and evaluating privacy schemes. In this paper, we propose a methodology to measure both the protection level of a privacy scheme and its impact on safety applications. We employ an empirical vehicle tracker to measure the effectiveness of a privacy scheme in terms of a number of confusions. We also measure its impact on a safety application by estimating the probability of correctly identifying the fundamental factors of that application using Monte Carlo analysis. Further, we propose an obfuscation privacy scheme which perturbs position and beacon frequency. Finally, we apply our methodology to evaluate the proposed scheme and compare it with the popular privacy scheme, random silent period. [less ▲]