Vehicular Message Exchange in Cross-border Scenarios Using Public Cloud Infrastructure

Cross-border scenarios are of extreme importance in current research work on 5G networks for connected vehicles. Network services and applications for connected vehicles, which are in specific cases expected to run on Mobile Edge Computing (MEC) infrastructure, might experience problems through country borders due to inter-domain. Given that cross-border scenarios typically imply a change of network operator, deployed MEC services need to work in such environments and, where applicable, different entities need to synchronize their input/output vehicular messages and work seamlessly in such a multi-operator context. One of most significant MEC services is vehicular message brokering. It consists on the controlled publishing and notification mechanisms to create awareness to all subscribed vehicles concerning their position as well as other significant events that may arise, such as hazardous events. This paper presents an architecture and method for vehicular message exchange, based on current Intelligent Transport Systems (ITS) standards, and proposes a novel hierarchical message brokering approach with the purpose of solving cross-domain scenarios, which can be applied not only in the aforementioned cross-border case but also in other scenarios where there is no single domain (i.e., with multiple vendors). Message Queuing Telemetry Transport (MQTT) servers are used in a hierarchical approach (locating a parent MQTT broker in a public cloud) in order to demonstrate the feasibility of using them for cross-border scenarios. Latency results are obtained in order to evaluate the performance penalty of the proposed solution.