STARC: Low-power Decentralized Coordination Primitive for Vehicular Ad-hoc Networks

Paper in proceeding, 2020

Intersections are the bottlenecks of road networks. Coordination mechanisms for intersection crossing greatly affect the efficiency of road utilization. Typically, coordination is done by implanting local infrastructure, whether signs, traffic lights, or through common, well known-rules shared by all users. In this paper, we introduce STARC, a decentralized intersection management protocol for future connected vehicles and other traffic participants. With STARC, all participants coordinate their movement using reservations to guarantee safe crossings. To enable cost-efficient deployment, STARC does neither rely on any centralized infrastructure, such as traffic lights, nor centralized wireless intersection coordinators, like virtual traffic lights. STARC targets small, cheap, and energy-efficient platforms and the open low-power wireless standard 802.15.4 so that all participants in road traffic could take advantage of it, including vehicles, bikes, electric scooters, and even pedestrians. STARC builds on low-power wireless communication with A2-Synchrotron and multi-hop routing as a communication substrate and provides distributed transaction, election, and handover mechanisms to manage the intersection cooperatively. We show that STARC reduces average waiting times by up to 50% compared to a fixed traffic light schedule in traffic volumes with less than 1000 vehicles per hour. Moreover, we illustrate a platoon extension that allows STARC to outperform traffic lights even at traffic loads beyond 1000 vehicles per hour.