Augmenting vehicular 3G users through inter-vehicle communications

Vehicular 3G (third-generation cellular system) users often need to download files from the Internet through the 3G data network, which is crucial in many application scenarios such as digital map update or location-based advertisement. Although the 3G brings larger coverage and instant access to data transfer, it may also incur high cost. We observe that many applications of vehicular 3G users can actually tolerate certain data access latency. In addition, inter-vehicle communications have been practical and can be exploited for inter-vehicle data delivery. Based on these observations, we propose to augment vehicular 3G users by data sharing through inter-vehicle communications. We formulate an optimization problem. The objective is to minimize the cost of 3G data communications, meanwhile maximizing the success probability of downloading all 3G user data. The two-hop transmission process and the bandwidth limitation in vehicular network are both modeled in the optimization problem. To lower the cost of 3G and meet the delivery ratio and delay constraints of data, one single-stage and one multi-stage algorithms are proposed for selection of seed vehicles (who download the data via 3G channel). We have evaluated our algorithm with simulations with real vehicular traces and the results show that our algorithms reduce the 3G cost and achieve good performance of data downloads.