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Section: New Results

VANET

Participant : Nathalie Mitton.

VANET (Vehicular Networks) is an arising kind of network which features specific functionalities and requirements especially in terms of delay.

[26] analyzes the information delivery delay for roadside unit deployment in an intermittently connected vehicular network. A mathematical model is developed to describe the relationship between the average information delivery delay and the distance between two neighbor RSUs (Road Side Unit) deployed along a road. The derived model considers a straight highway scenario where two RSUs are deployed at a distance without any direct connection and vehicles are sparsely distributed on the road with road condition information randomly generated between the two neighbor RSUs. Moreover, the model takes into account the vehicle speed, the vehicle density, the likelihood of an incident, and the distance between two RSUs. The effectiveness of the derived mathematical model is verified through simulation results. Given the delay requirement of some time-critical applications, this model can be used to estimate the maximum distance allowed between two neighbor RSUs, which can provide a reference basis for the deployment of RSUs in such scenarios.

Abstract–Broadcasting is an effective routing paradigm for data dissemination in vehicular ad hoc networks (VANETs). One concern that arises with broadcasting is the broadcast storm problem, which would cause node contentions and data collisions, and thus degrade the transmission efficiency of a network. [27] proposes a Dynamic trAnsmission delaY based broadcast (DAYcast) protocol for a VANET. To alleviate the effect of the broadcast storm and improve the transmission efficiency of the network, DAYcast only allows the effective neighbors of a source vehicle to broadcast a received data packet and the selection of the effective neighbors are based on the position information on the one-hop neighbors of the source vehicle. Meanwhile, it allows each effective neighbor to wait a certain transmission delay before it broadcasts a received packet. The transmission delay of an effective neighbor depends on the distance between the neighbor and the source vehicle, and the number of effective neighbors of the source vehicle. Simulation results show that DAYcast can effectively improve the network performance in terms of network reachability and the successful delivery ratio as compared with existing weighted p-persistence broadcasting (WPB) and slotted 1-persistence broadcasting (SPB).