Delay-bounded routing in vehicular ad-hoc networks

Abstract

Ad hoc networks formed by traveling vehicles are envisaged to become a common platform that will support a wide variety of applications, ranging from road safety to advertising and entertainment. The multitude of vehicular applications calls for routing schemes that satisfy user-defined delay requirements while at the same time maintaining a low level of channel utilization to allow their coexistence. This paper focuses on the development of carry-and-forward schemes that attempt to deliver data from vehicles to fixed infrastructure nodes in an urban setting. The proposed algorithms leverage local or global knowledge of traffic statistics to carefully alternate between the Data Muling and Multihop Forwarding strategies, in order to minimize communication overhead while adhering to delay constraints imposed by the application. We provide an extensive evaluation of our schemes using realistic vehicular traces on a real city map.

Using Real-Time Road Traffic Data to Evaluate Congestion

“…Researchers and the automotive industry are envisioning the deployment of a large spectrum of applications running on VANETs, including notification services for accidents and traffic congestion. Our TIME collaborators at the University of Oxford have investigated VANETs in the context of probe data [20][21][22]. They leverage connectivity between travelling vehicles in an urban area to propagate traffic information generated by vehicles to stationary gateways spread across the city.…”

“…When traffic density is low or when only few vehicles participate, the vehicular network often becomes disconnected. Carry-and-forward protocols are proposed for the reliable delivery of messages between vehicles in dynamically changing network partitions [20]. These data forwarding protocols exploit knowledge of traffic statistics in an urban setting to enable timely delivery of messages from vehicles to stationary gateways, whilst minimizing message transmissions and optimizing bandwidth utilization.…”

The multi-copy diversity for routing in sparse vehicular ad hoc networks

“…VANETs at low densities may get disconnected due to low node density at the time of day such as night times or low deployment rate at market introduction phase [2,5,6,10,14,15]. As a result, a mobile node can be used as a carrier to deliver messages, i.e., store-and-carry forwarding which is a technique developed by the delay tolerant network (DTN) community [1,11].…”

“…We refer to this phenomenon as multi-copy diversity gain, and the multicopy diversity effect on DTNs with random mobility is evaluated in [16]. Epidemic routing, with some improvements, has recently been applied to the vehicular networks to combat the network disconnection problem [2,5,6,10,15]. The main difference of epidemic routing in vehicular networks is that the packet replication is only made at the intersection, where multiple available road paths to the destination may exist.…”

“…We show that AMR achieves multi-copy diversity close to maximum while limiting the routing overhead. AMR also utilizes only the local delay measurements, while previous sparse routing protocols [2,10,15] requires global network information at real time.…”