Improving VANET Protocols via Network Science

Developing routing protocols for Vehicular Ad Hoc Networks (VANETs) is a significant challenge in these large, self- organized and distributed networks. We address this challenge by studying VANETs from a network science perspective to develop solutions that act locally but influence the network performance globally. More specifically, we look at snapshots from highway and urban VANETs of different sizes and vehicle densities, and study parameters such as the node degree distribution, the clustering coefficient and the average shortest path length, in order to better understand the networks' structure and compare it to structures commonly found in large real world networks such as small-world and scale-free networks. We then show how to use this information to improve existing VANET protocols. As an illustrative example, it is shown that, by adding new mechanisms that make use of this information, the overhead of the urban vehicular broadcasting (UV-CAST) protocol can be reduced substantially with no significant performance degradation.Comment: Proceedings of the 2012 IEEE Vehicular Networking Conference (VNC), Korea, November 201

Cars as roadside units: a selforganizing network solution

Abstract Deploying Roadside Units (RSUs) for increasing the connectivity of vehicular ad hoc networks is deemed necessary for coping with the partial penetration of Dedicated Short Range Communications (DSRC) radios into the market at the initial stages of DSRC deployment. Several factors including cost, complexity, existing systems, and lack of cooperation between government and private sectors have impeded the deployment of RSUs. In this paper, we propose to solve this formidable problem by using a biologically inspired self-organizing network approach whereby certain vehicles serve as RSUs. The proposed solution is based on designing local rules and the corresponding algorithms that implement such local rules. Results show that the proposed approach can increase the message reachability and connectivity substantially

Comparison of Radio Frequency and Visible Light Propagation Channels for Vehicular Communications

Recent research has shown that both radio and visible light waves can be used to enable communications in highly dynamic vehicular environments. However, the roles of these two technologies and how they interact with each other in future vehicular communication systems remain unclear. Understanding the propagation characteristics is an essential step in investigating the benefits and shortcomings of each technology. To this end, we discuss salient properties of radio and visible light propagation channels, including radiation pattern, path loss modeling, noise and interference, and channel time variation. Comparison of these properties provides an important insight that the two communication channels can complement each other’s capabilities in terms of coverage and reliability, thus better satisfying the diverse requirements of future cooperative intelligent transportation systems

Cars as Roadside Units: A Self-Organizing Network Solution

<p>Deploying roadside units, RSUs, for increasing the connectivity of vehicular ad hoc networks is deemed necessary for coping with the partial penetration of DSRC radios into the market in the initial stages of DSRC deployment. Several factors, including cost, complexity, existing systems, and lack of cooperation between government and private sectors, have impeded the deployment of RSUs. In this article, we propose to solve this formidable problem by using a biologically inspired self-organizing network approach whereby certain vehicles serve as RSUs. The proposed solution is based on designing local rules and the corresponding algorithms that implement them. Results show that the proposed approach can increase the message reachability and connectivity substantially.</p

Cars as Roadside Units: A Cooperative Solution

<p>The gradual penetration of Dedicated Short Range Communications Radio (DSRC) technology in the years to come is a formidable problem that could adversely affect the implementation of safety and non-safety applications. In this paper, we propose a solution that might mitigate the negative impact of the partial and gradual penetration problem of DSRC technology. The proposed solution is based on a self-organizing network paradigm that draws its inspiration from biological systems, such as social insect colonies [1]. By designing the local rules and a distributed algorithm needed to perform this function, it is shown that DSRC equipped cars can indeed serve as RSUs. Results show that the message reachability and connectivity in urban vehicular networks can be increased substantially in a cost-effective manner as the proposed approach does not entail deployment of infrastructure based RSUs.</p

Priority Management of Emergency Vehicles at Intersections Using Self-organized Traffic Control

<p>Biologically inspired approaches have the potential to solve many of the difficult networking problems awaiting practical solutions. The recently proposed Virtual Traffic Lights (VTL) is one example (or instance) of this powerful approach for solving some fundamental transportation problems[1], [2]. The successful operation of VTL scheme ultimately depends on the local rules used by vehiclesapproaching an intersection for electing a leader that manages the traffic at that intersection by serving as a virtual traffic light. In this paper, it is shown that by using a different set of local rules atintersections, one can support priority management of emergency vehicles in a self-organized manner. The proposed VTL-Priority Intersection Control (VTL-PIC) protocol can detect the presence of anemergency vehicle and assign priority to the emergency vehicle at an intersection. Large-scale simulation results show that while the travel time of emergency vehicles can be reduced significantly, the impact of the proposed algorithm on the travel time of other vehicles is negligible.</p

Accelerating the Adoption of Virtual Traffic Lights through Policy Decisions

A new technology known as Virtual Traffic Lights (VTL) was recently proposed as a self-organizing new paradigm for traffic management. This new technology uses the vehicle-to-vehicle (V2V) communications as its premise. VTL can revolutionize traffic management in urban areas as it can substantially reduce commute time of urban workers, increase productivity, and lead to a greener environment. In a VTL environment, vehicles self-organize to elect a leader which serves as a virtualtraffic light to decide the right of way at that intersection, thus replacing the current physical traffic lights. Implementing VTL technology with partial penetration, however, is an outstanding issue that needs to be addressed. This paper addresses this issue by proposing a co-existence model whereby VTL equipped vehicles can co-exist with vehicles that do not have VTL. Simulation results show that the transition model proposed here could provide drivers with strong incentives to adopt the VTL technology.</p