Reliability and energy-efficiency analysis of safety message broadcast in VANETs

Safety applications in vehicular ad hoc networks (VANETs) rely heavily on broadcast schemes for the exchange of status messages. Reliable and on-time delivery of safety messages is critical in VANETs that requires extremely efficient broadcast models. In this paper, we model the reliability of flooding used as the underlying data dissemination protocol for time-critical safety messages. We consider a multi-hop VANET and model end-to-end reliability provided by the network layer. The analytical results unleash important insights about the flooding mechanism. For instance, the reliability drops exponentially beyond a certain threshold value of packet loss probability. Secondly, the impact of hop length on reliability can be catastrophic if not handled appropriately. Keeping in view of the fact that energy-efficient protocols is a key requirement in the upcoming Internet of Vehicles (IoV), we also show that restrictive flooding is more energy-efficient than plain flooding under the same reliability constraint. We validate our theoretical findings through simulations and propose modifications to plain flooding to make it more reliable.