L-Platooning: A Protocol for Managing a Long Platoon with DSRC

Vehicle platooning is an automated driving technology that enables a group of vehicles to travel very closely together as a single unit to improve fuel efficiency and driver safety and reduces CO2 emission. The significant benefits of platooning attracted huge interests from academia and industry, especially from logistics companies for utilizing platoons of "long-body" trailer trucks because of the huge cost savings. In this paper, we demonstrate that existing DSRC-based platooning solutions, however, fail to support formation of such "long" platoons consisting of typical trailer trucks because of the limited communication range of DSRC. To address this problem, we propose L-Platooning, the first platooning protocol that enables seamless, reliable, and rapid formation of a long platoon. We introduce a novel concept called Virtual Leader that refers to a vehicle that acts like a platoon leader to extend the coverage of the original platoon leader. A virtual leader election algorithm is developed to effectively designate a virtual leader based on the novel metric called the Virtual Leader Quality Index (VLQI) which quantifies the effectiveness of a vehicle serving as a platoon leader. We also develop mechanisms for L-Platooning to support the vehicle join and leave maneuvers specifically for a long platoon. Through extensive simulations using the combination of Veins (Plexe) and SUMO, we demonstrate that L-Platooning enables long-body trailer trucks to form a long platoon effectively and maintain the desired inter-vehicle distance precisely. We also show that L-Platooning handles seamlessly the vehicle join and leave maneuvers for a long platoon.