Institute of Electrical & Electronic Engineers
Reliability is a critical concern in disseminating safety messages in Vehicular Ad-hoc-NETworks (VANETs). Thus far, redundant broadcast (or next relay broadcast) has been used to ensure reliable transfer of safety messages. However, redundant broadcast fails to meet high-reliability requirement owing to lack of a feedback or ACKnowledgment (ACK) mechanism. In this paper, a power controlled Negative-ACKnowledgment (NACK) mechanism is introduced as a feedback technique to ensure reliable reception of safety messages. Significantly, this paper also attempts to cover vehicles present in transmission holes in the broadcast region. Vehicles in the immediate neighborhood detect and recover safety message for a vehicle present in the transmission hole by estimating propagation loss for the vehicle.