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

Adoption of vehicular ad hoc networking protocols by networked robots

This paper focuses on the utilization of wireless networking in the robotics domain. Many researchers have already equipped their robots with wireless communication capabilities, stimulated by the observation that multi-robot systems tend to have several advantages over their single-robot counterparts. Typically, this integration of wireless communication is tackled in a quite pragmatic manner, only a few authors presented novel Robotic Ad Hoc Network (RANET) protocols that were designed specifically with robotic use cases in mind. This is in sharp contrast with the domain of vehicular ad hoc networks (VANET). This observation is the starting point of this paper. If the results of previous efforts focusing on VANET protocols could be reused in the RANET domain, this could lead to rapid progress in the field of networked robots. To investigate this possibility, this paper provides a thorough overview of the related work in the domain of robotic and vehicular ad hoc networks. Based on this information, an exhaustive list of requirements is defined for both types. It is concluded that the most significant difference lies in the fact that VANET protocols are oriented towards low throughput messaging, while RANET protocols have to support high throughput media streaming as well. Although not always with equal importance, all other defined requirements are valid for both protocols. This leads to the conclusion that cross-fertilization between them is an appealing approach for future RANET research. To support such developments, this paper concludes with the definition of an appropriate working plan

Dissimilarity metric based on local neighboring information and genetic programming for data dissemination in vehicular ad hoc networks (VANETs)

This paper presents a novel dissimilarity metric based on local neighboring information and a genetic programming approach for efficient data dissemination in Vehicular Ad Hoc Networks (VANETs). The primary aim of the dissimilarity metric is to replace the Euclidean distance in probabilistic data dissemination schemes, which use the relative Euclidean distance among vehicles to determine the retransmission probability. The novel dissimilarity metric is obtained by applying a metaheuristic genetic programming approach, which provides a formula that maximizes the Pearson Correlation Coefficient between the novel dissimilarity metric and the Euclidean metric in several representative VANET scenarios. Findings show that the obtained dissimilarity metric correlates with the Euclidean distance up to 8.9% better than classical dissimilarity metrics. Moreover, the obtained dissimilarity metric is evaluated when used in well-known data dissemination schemes, such as p-persistence, polynomial and irresponsible algorithm. The obtained dissimilarity metric achieves significant improvements in terms of reachability in comparison with the classical dissimilarity metrics and the Euclidean metric-based schemes in the studied VANET urban scenarios

Previous hop routing: exploiting opportunism in VANETs

Routing in highly dynamic wireless networks such as Vehicular Ad-hoc Networks (VANETs) is a challenging task due to frequent topology changes. Sustaining a transmission path between peers in such network environment is difficult. In this thesis, Previous Hop Routing (PHR) is poposed; an opportunistic forwarding protocol exploiting previous hop information and distance to destination to make the forwarding decision on a packet-by-packet basis. It is intended for use in highly dynamic network where the life time of a hop-by-hop path between source and destination nodes is short. Exploiting the broadcast nature of wireless communication avoids the need to copy packets, and enables redundant paths to be formed. To save network resources, especially under high network loads, PHR employs probabilistic forwarding. The forwarding probability is calculated based on the perceived network load as measured by the arrival rate at the network interface. We evaluate PHR in an urban VANET environment using NS2 (for network traffic) and SUMO (for vehicular movement) simulators, with scenarios configured to re ect real-world conditions. The simulation scenarios are configured to use two velocity profiles i.e. Low and high velocity. The results show that the PHR networks able to achieve best performance as measured by Packet Delivery Ratio (PDR) and Drop Burst Length (DBL) compared to conventional routing protocols in high velocity scenarios