Safety Data Dissemination Framework For Vehicular Networks

"An effective transportation system is essential to modern societies with transportation having a significant influence on economic growth, social development and the environment. But this dependence on road mobility has had serious consequences in terms of rising crash costs that include deaths, injuries, lost productivity, material damage and congestion. The European Union and many other governments worldwide support active safety as being the next logical step in diminishing crash costs after passive safety (safety belt, ABS etc.) where drivers will be warned prior to reaching hazardous situations enabling them to react appropriately. While improving road safety is unanimously considered the major driving factor for the deployment of Intelligent Vehicle Safety Systems, the challenges relating to reliable multi-hop broadcasting are exigent in vehicular networking. Broadcast protocols for Vehicular Ad-hoc Networks (VANET) must guarantee fast and reliable delivery of information to all vehicles in the neighbourhood, where the wireless communication medium is shared and highly unreliable with limited bandwidth. This thesis presents a broadcast communications protocol, the Reliable Vehicular Geobroadcast (RVG) protocol specifically designed for Vehicular Ad-hoc Networks (VANET) where the emphasis is on satisfying requirements for safety applications with respect to delay, packet delivery and overhead. The RVG protocol was compared with existing broadcast protocols in a complex realistic vehicular simulation environment including sample urban and highway test network scenarios using safety warning and SOS warning services to test the effectiveness of the protocols in disseminating warning messages. The evaluation results highlight that the existing broadcast protocols for vehicular safety application dissemination are not satisfactory for safety application requirements (packet delivery, delay and overhead) across a range of vehicular network environments. In contrast, the RVG protocol has been demonstrated to overcome these drawbacks - RVG is a robust broadcast protocol suitable as a general purpose dissemination mechanism for a range of safety applications over diverse vehicular environments in targeted geographical areas that satisfies safety data dissemination requirements with high packet delivery, low delay and low overhead."