Vehicle-to-infrastructure messaging proposal based on CAM/DENM specifications

The European Telecommunications Standards Institute (ETSI) has proposed a middleware solution (called facility) to support vehicular safety and traffic efficiency services needing continuous status information about surrounding vehicles or wanting to send asynchronous warning notifications to vehicles. The former capability is offered by the Cooperative Awareness Basic Service, while the latter is provided by the Decentralized Environmental Notification Basic Service. Reference packet formats for both the Cooperative Awareness Message (CAM) and Decentralized Environmental Notification Message (DENM) have been specified by ETSI, together with the general message dissemination guidelines. This paper presents an implementation prototype that has been developed to validate both CAM and DENM messaging capabilities. We provide implementation decisions and demonstrate the usefulness of these facilities through two reference services which provide a way to third-party services to gather tracking and tracing information, and send asynchronous road events to drivers within a specific area.