1,068 research outputs found
The Dynamics of Vehicular Networks in Urban Environments
Vehicular Ad hoc NETworks (VANETs) have emerged as a platform to support
intelligent inter-vehicle communication and improve traffic safety and
performance. The road-constrained, high mobility of vehicles, their unbounded
power source, and the emergence of roadside wireless infrastructures make
VANETs a challenging research topic. A key to the development of protocols for
inter-vehicle communication and services lies in the knowledge of the
topological characteristics of the VANET communication graph. This paper
explores the dynamics of VANETs in urban environments and investigates the
impact of these findings in the design of VANET routing protocols. Using both
real and realistic mobility traces, we study the networking shape of VANETs
under different transmission and market penetration ranges. Given that a number
of RSUs have to be deployed for disseminating information to vehicles in an
urban area, we also study their impact on vehicular connectivity. Through
extensive simulations we investigate the performance of VANET routing protocols
by exploiting the knowledge of VANET graphs analysis.Comment: Revised our testbed with even more realistic mobility traces. Used
the location of real Wi-Fi hotspots to simulate RSUs in our study. Used a
larger, real mobility trace set, from taxis in Shanghai. Examine the
implications of our findings in the design of VANET routing protocols by
implementing in ns-3 two routing protocols (GPCR & VADD). Updated the
bibliography section with new research work
A topology-oblivious routing protocol for NDN-VANETs
Vehicular Ad Hoc Networks (VANETs) are characterized by intermittent
connectivity, which leads to failures of end-to-end paths between nodes. Named
Data Networking (NDN) is a network paradigm that deals with such problems,
since information is forwarded based on content and not on the location of the
hosts. In this work, we propose an enhanced routing protocol of our previous
topology-oblivious Multihop, Multipath, and Multichannel NDN for VANETs
(MMM-VNDN) routing strategy that exploits several paths to achieve more
efficient content retrieval. Our new enhanced protocol, i mproved MMM-VNDN
(iMMM-VNDN), creates paths between a requester node and a provider by
broadcasting Interest messages. When a provider responds with a Data message to
a broadcast Interest message, we create unicast routes between nodes, by using
the MAC address(es) as the distinct address(es) of each node. iMMM-VNDN
extracts and thus creates routes based on the MAC addresses from the strategy
layer of an NDN node. Simulation results show that our routing strategy
performs better than other state of the art strategies in terms of Interest
Satisfaction Rate, while keeping the latency and jitter of messages low
Evaluation study of IEEE 1609.4 performance for safety and non-safety messages dissemination
The IEEE 1609.4 was developed to support multi-channel operation and channel switching procedure in order to provide both safety and non-safety vehicular applications. However, this protocol has some drawback because it does not make efficient usage of channel bandwidth resources for single radio WAVE devices and suffer from high bounded delay and lost packet especially for large-scale networks in terms of the number of active nodes. This paper evaluates IEEE 1609.4 multi-channel protocol performance for safety and non-safety application and compare it with the IEEE 802.11p single channel protocol. Multi-channel and single channel protocols are analyzed in different environments to investigate their performance. By relying on a realistic dataset and using OMNeT++ simulation tool as network simulator, SUMO as traffic simulator and coupling them by employing Veins framework. Performance evaluation results show that the delay of single channel protocol IEEE 802.11p has been degraded 36% compared with multi-channel protocol
Stable Infrastructure-based Routing for Intelligent Transportation Systems
Intelligent Transportation Systems (ITSs) have been instrumental
in reshaping transportation towards safer roads, seamless
logistics, and digital business-oriented services under the umbrella of
smart city platforms. Undoubtedly, ITS applications will demand
stable routing protocols that not only focus on Inter-Vehicle Communications
but also on providing a fast, reliable and secure interface to
the infrastructure. In this paper, we propose a novel stable infrastructure-
based routing protocol for urban VANETs. It enables vehicles
proactively to maintain fresh routes towards Road-Side Units
(RSUs) while reactively discovering routes to nearby vehicles. It
builds routes from highly stable connected intersections using a selection
policy which uses a new intersection stability metric. Simulation
experiments performed with accurate mobility and propagation
models have confirmed the efficiency of the new protocol and its
adaptability to continuously changing network status in the urban
environment
Routing And Communication Path Mapping In VANETS
Vehicular ad-hoc network (VANET) has quickly become an important aspect of the intelligent transport system (ITS), which is a combination of information technology, and transport works to improve efficiency and safety through data gathering and dissemination. However, transmitting data over an ad-hoc network comes with several issues such as broadcast storms, hidden terminal problems and unreliability; these greatly reduce the efficiency of the network and hence the purpose for which it was developed. We therefore propose a system of utilising information gathered externally from the node or through the various layers of the network into the access layer of the ETSI communication stack for routing to improve the overall efficiency of data delivery, reduce hidden terminals and increase reliability. We divide route into segments and design a set of metric system to select a controlling node as well as procedure for data transfer. Furthermore we propose a system for faster data delivery based on priority of data and density of nodes from route information while developing a map to show the communication situation of an area. These metrics and algorithms will be simulated in further research using the NS-3 environment to demonstrate the effectiveness
Vehicle density in VANET Applications
This paper analyzes how street-level traffic data affects routing in VANETs applications. First, we offer a general review about which protocols and techniques would fit best for VANET applications. We selected five main technical aspects (Transmission, Routing, Quality of Service, Security and Location) that we consider are differential aspects of VANETs from current Ad-Hoc Networks. Second, the paper analyzes how to configure each technical aspect according to the goal of a wide range of VANET applications. Third, we look at the routing aspect in depth, specifically focusing on how vehicle density affects routing, which protocols are the best option when there is a high/low density, etc. Finally, this research implements a sensor technology, based on an acoustics sensor that has been deployed around the city of Xalapa in MĂ©xico, to obtain reliable information on the real-time density of vehicles. The levels of density were discretized and the obtained data samples were used to feed a traffic simulator, which allowed us to obtain a global picture of the density of the central area of the city. According to the specific levels of vehicle density at a specific moment and place, VANET applications may adapt the routing protocol in a real-time wayPeer ReviewedPostprint (published version
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