Efficient Data Dissemination in Urban VANETs: Parked Vehicles Are Natural Infrastructures

Data dissemination is the fundamental operation in vehicular ad hoc networks (VANETs); for example, after an accident or congestion is detected by the corresponding sensors mounted on the vehicles, an alert message should be swiftly disseminated to the vehicles moving towards the affected areas. However, the unique characteristics of VANETs, such as high mobility of vehicle nodes, intermittent connectivity, and rapidly dynamic topology, make data dissemination over them extremely challenging. Motivated by the fact that there are large amounts of roadside parked vehicles in urban areas, this paper proposes a parking-based data dissemination scheme for VANETs. Data to be disseminated are buffered at the roadside parked vehicle, which continuously provides data dissemination services for the vehicles passing by. We analyze the challenging issues in achieving parking-based data dissemination and provide possible solution for each issue. Theoretical results illustrate the effectiveness of our approach, and simulation results based on a real city map and realistic traffic situations show that the proposed data dissemination paradigm achieves a higher delivery ratio with lower network load and reasonable delivery delay.