A Redundancy-Based Protocol for Safety Message Dissemination in Vehicular Ad Hoc Networks

The diversity of applications' types in vehicular ad hoc networks (VANETs) has spawned a large variety of messages that need to be disseminated in a vehicle to vehicle (V2V) communication mode. The most critical messages are those dedicated for safety applications such as accident warning, road hazardous warning, signal violation warning, etc. The dissemination of this kind of messages is a challenging task in VANETs since they should be efficiently transmitted i.e. by achieving high packet delivery within a limited transmission delay and an acceptable overhead. In this work, we propose a robust and an original data dissemination protocol called ``Redundancy-based Protocol (RBP)''. Unlike most of density-based protocols, RBP is beaconless. It takes into account the surrounding vehicles' density during the broadcasting process through a specific metric, named ``Packet Redundancy Ratio'', calculated locally at each vehicular node. On the basis of this metric, each vehicle is able to dynamically define the probability of rebroadcast in order to mitigate the broadcast storm problem. The simulation results show that the proposed protocol outperforms the slotted 1-persistence scheme in terms of packet drop ratio, and network load while still maintaining a low End-to-End delay and high packet reachability. This scheme is suitable either for safety applications or for further kinds of applications by saving the network capacity consumption.