An Error Protection Protocol for the Multicast Transmission of Data Samples in V2X Applications

There is a trend towards communication of larger data objects in wireless vehicle communication. In many cases, communication uses publish-subscribe protocols. Data rate requirements of such protocols are best addressed by wireless multicast protocols, but the existing protocols lack an error protection that is suitable for real-time and safety-critical applications. We present an application-aware protocol that supports the popular DDS (Data Distribution Service) middleware. By exploiting data object deadlines and slack for retransmissions and employing an adaptable, multicast-aware prioritization mechanism, the reliable exchange of large data objects is enabled. The protocol is sufficiently general to be used on top of different communication standards such as 802.11- and cellular-based V2X (Vehicle-to-Everything) technologies. The protocol was implemented in an OMNeT++ simulation model and evaluated against recent state-of-the-art alternatives using parameters and constraints taken from a motivational truck platooning example. Furthermore, the protocol was implemented using an open-source DDS implementation as the basis and tested on a physical wireless demonstrator setup. The evaluation shows that the presented multicast protocol substantially outperforms the alternatives keeping streaming applications operational even under high frame error rates.