Analysis of the Intra-Platoon Message Delivery Delay in a Platoon of Vehicles

A platoon of connected and automated vehicles (CAVs) is one of the promising autonomous-driving applications. Vehicles in a platoon need timely delivery of road-safety information in order to alter their speeds in time and thus maintain the stability of the platoon. The intra-platoon message delivery delay is a critical metric that has a big impact on the maintenance of a platoon's stability. It depends on several system parameters, such as the number of vehicles in a platoon, the intra-platoon spacing, and the distribution of non-platoon vehicles. This paper studies the analysis of the intra-platoon message delivery delay in a platoon of CAVs moving on a highway road. A theoretical analytical model is derived to investigate the impacts of major system parameters on the intra-platoon message delivery delay. The derived analytical model considers a V2V hop-by-hop communication mode and takes into account the effects of both platoon and non-platoon vehicle nodes on channel access contention. The effect of hidden vehicle nodes is also considered. The derived analytical model is validated through simulation results and the impacts of major system parameters on the intra-platoon message delivery delay are investigated through numerical results. The derived analytical model can be used to provide reasonable reference values for system parameter setting in order to maintain the stability of an autonomous-driving platoon.