Schemes for Enabling Vehicles Parked Out-of-RSU Range to Participate in Group Communication

As vehicular technology matures, various monitoring devices that are operational, even when the vehicle is parked, are being developed and installed. When the vehicular ad-hoc network (VANET) is commercialized, it is expected that these devices will be able to transmit the data collected to other vehicles or the owner of a vehicle, wirelessly. To accomplish this, group communication can be employed for security and efficiency. However, if a vehicle is parked out of communication range of a roadside unit (RSU) when a group key is modified, it cannot participate in the group communication. Moreover, even when the parked vehicle has the latest group key, transmitting large amounts of data remains problematic. In this paper, we propose solutions that enable vehicles parked out of the communication range of RSU to participate in group communication. First, we provide a running-vehicle-to-parked-vehicle group key transmission scheme. Second, we develop a scheme for transmitting large files. Using these two schemes, the parked vehicle can not only participate in group communication when the group key is changed, but also transmit large amounts of data, such as a blackbox clips, to the owner of a vehicle or other passing vehicles. In security analysis, we prove that the proposed scheme is protected from common attack scenarios.