Coordination-free Safety Messages Dissemination Protocol for Vehicular Networks

Many vehicular safety applications depend on the rapid and reliable dissemination of safety messages to vehicles at risk. In order to allow sufficient reaction time for emergency events in adverse driving and road conditions, disseminating safety messages over multi-hop vehicles is often needed. However, owing to the capacity limitation of the shared control channel, disseminating safety messages in highly mobile and dynamic vehicular network conditions is challenging. In this article, a Zero-Coordination Opportunistic Routing (ZCOR) algorithm is proposed to deliver mission-critical life safety messages over limited target geocast regions. ZCOR is scalable and robust over dynamic VANET conditions with low rebroadcast overhead. In addition, ZCOR exploits neighbor knowledge for coordinationfree opportunistic packet relay using the novel concept of Circle of Trust (CoT), which defines the range of reliable local neighbor knowledge collection. The performance of ZCOR is evaluated through extensive and realistic simulations capturing time-correlated vehicular channel characteristics.