Abstract-Classical ad-hoc network algorithms become impractical for Vehicular Ad Hoc Networks when density of vehicles is low in rural areas and during the periods when the vehicle traffic is low in cities (such as at night). End-to-end connectivity requirement of these algorithms causes deflection. Connections get broken when a suitable network element isn't available for data transfer. This problem which occurs in low dense partially connected Vehicular Ad hoc Networks can be solved by using delay tolerant approaches in routing algorithms. By using the store-carry-forward method, data is carried by network elements until a suitable network element is found. By this way, network connectivity is provided in a delayed manner between momentarily disconnected vehicles. In this paper, the impact of delayed transfer of data to an end-to-end transfer and the impact of data lifetime to the network performance are examined. Considering the speed of vehicles and the desired throughput, lifetime of data is determined according to the network connectivity. The results of this study contribute to the fulfilment of the Quality of Service (QoS) requirements in Vehicular Ad Hoc Network applications.
I. INTRODUCTION Studies on VehicularNetworks has expedited in recent years and this technology become applicable as a result of advances in wireless communications. Though the initial studies oriented to safety, its applicability to other areas such as business, entertainment, driving assist and public services, studies enlarged to comprise these new areas.Vehicular Ad Hoc Networks use the DSRC (Dedicated Short Range Communications) [1] standard presenting high data rate (6-27Mbps) which has a bandwidth of 75MHz and band of 5.9GHz. With DSRC, vehicles on the road broadcast the routine traffic message which includes location, time, direction, speed and traffic condition information. Additionally, emergency messages (e.g. accident, emergency brake) are sent on emergency conditions. While the routine messages are single-hop beaconing messages, emergency messages can be sent over multiple-hop paths.The main advantage of Vehicular Ad Hoc Networks is their applicability as an alternative communication network in case of catastrophes such as earthquake, flood etc. due to adhoc nature which does not require network infrastructure.