Enabling Distributed Control of Vehicle Platooning via Over-the-Air Consensus

A distributed control of vehicle platooning is referred to as distributed consensus (DC) since many autonomous vehicles (AVs) reach a consensus to achieve coordinated movement with the same velocity and inter-distance. For DC control to be stable, each AV utilizes other AVs' real-time position information obtained via vehicle-to-vehicle (V2V) communications. On the other hand, too many V2V links should be simultaneously established and frequently retrained, causing a longer communication latency due to frequent packet losses and thereby hampering stable DC. This paper proposes a novel DC algorithm called over-the-air consensus (AirCons), a joint communication-and-control design with two key features to overcome the above limitations. First, exploiting a wireless signal's superposition and broadcasting properties renders every AV's signal converge to a specific value. We show that the consensus value is proportional to the weighted average of participating AVs' real-time positions and has a tight lower bound as the ground-truth average. In other words, the average position location can be directly estimated without the neighbor AVs' positions, thereby achieving ultra-low latency data sharing. Next, the estimated average position is inputted into each AV's controller to adjust its dynamics distributively. The average position, considered a real-time value due to its low latency, contributes to achieving the stability of vehicle platooning. We design AirCons based on New Radio architecture with its feasibility study by analyzing required radio resources, i.e., time and bandwidth. Through analytic and numerical studies, the effectiveness of the proposed AirCons is verified by showing a 16.40% control gain compared to the benchmark without the average position.