Information Dissemination Delay in Vehicle-to-Vehicle Communication Networks in a Traffic Stream (original) (raw)
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2013 IEEE International Symposium on Information Theory, 2013
In this paper, we study the information propagation speed in multi-lane vehicle-tovehicle networks such as multi-lane roads or highways. We focus on the impact of time-varying radio ranges and of multiple lanes of vehicles, varying in speed and in density. We assess the existence of a vehicle density threshold under which information propagates on average at the fastest vehicle speed and above which information propagates dramatically faster. We first prove that no such phase transition occurs if there is only one lane, regardless of the density of vehicles, when one takes into account real-time radio communication range variations at the MAC layer. We then prove that, on the other hand, a phase transition exists as soon as there are multiple lanes with different vehicle speeds and appropriate densities. We characterize conditions under which the phase transition occurs and we derive bounds on the corresponding threshold as a simple relationship between the vehicle density on the fastest lane and the sum of the vehicle densities on the other lanes. Our results intrinsically encompass a wide range of vehicular network scenarios, including one-way and two-way roads, as well as special cases such as road side units and/or parked cars being used as relays. We confirm our analytical results using simulations carried out in several environments (ONE and Maple).
Instantaneous information propagation in a traffic stream through inter-vehicle communication
Transportation Research Part B-methodological, 2006
The advancement of wireless communication technology has made possible the consideration of inter-vehicle communication as a foundation for developing decentralized advanced transportation information systems that would function as a sort of "internet on the road". In this paper, we discuss the reliability of inter-vehicle communication in a traffic stream, dependent on the distribution of equipped vehicles. With the assumption that information propagation is instantaneous compared to vehicle movements, the reliability is measured by the probability of success for information to travel beyond a location; stochastic models are presented for both uniform and general traffic streams. In the models, the traffic stream is divided into a series of cells based on the transmission range, the structure of possible most-forward-within-range communication chains is clarified, the probabilities for information to travel to and beyond a vehicle at a certain hop are computed regressively, and the lower bound of the absolute success rate for information to travel beyond a point is determined. Based on the models, we examine the performance of information propagation for different penetration rates, transmission ranges, and traffic scenarios that include gaps and shock waves. Finally, some implications and future extensions of this effort are discussed.
The process of information propagation in a traffic stream with a general vehicle headway: A revisit
Transportation Research Part C: Emerging Technologies, 2010
Effective intervehicle communication is fundamental to a decentralized traffic information system based on mobile ad hoc vehicle networks. Here we model the information propagation process through inter-vehicle communication when the vehicle headway follows a general distribution. Equations for the expected value and variance of propagation distance are derived. In addition, we provide simple equations for the expected number of vehicles covered and the probability distribution of propagation distance. This research advances on an earlier study where the vehicle headway is assumed to follow an exponential distribution. This paper generalizes the earlier results and enables a design for robust information propagation by allowing for examination of the impact of different headway distributions. Within the new modeling framework, we also compute connectivity between two vehicles.
A Study on Information Throughput of Inter-vehicle Communications in a Unidirectional Traffic Stream
In this paper, we study throughput in an IVC system along a unidirectional traffic for different traffic conditions and transmission ranges of wireless units. Here, whether a vehicle is equipped or not is random, and the probability is assumed to be the market penetration rate. We first briefly introduce the communication performance measures and our simulation platform based on network simulator 2 and traffic flow theories. We then present Monte Carlo simulation results of communication performance measures for traffic flows of two congestion levels, information source and destination at different distances, and three transmission ranges. We compare our results with those obtained through simple connectivity analysis and find that the results are consistent for low connectivity, but the throughputs by ns-2 simulations are significantly lower than the theoretical results, due to packet losses caused by signal interferences. Together with further investigations, the study could be helpful for determining and designing appropriate communication hardware and software and intelligent transportation applications.
Highway Vehicular Delay Tolerant Networks: Information Propagation Speed Properties
IEEE Transactions on Information Theory, 2000
In this paper, we provide a full analysis of the information propagation speed in bidirectional vehicular delay tolerant networks such as roads or highways. The provided analysis shows that a phase transition occurs concerning the information propagation speed, with respect to the vehicle densities in each direction of the highway. We prove that under a certain threshold, information propagates on average at vehicle speed, while above this threshold, information propagates dramatically faster at a speed that increases quasi-exponentially when the vehicle density increases. We provide the exact expressions of the threshold and of the average information propagation speed near the threshold, in case of finite or infinite radio propagation speed. Furthermore, we investigate in detail the way information propagates under the threshold, and we prove that delay tolerant routing using cars moving on both directions provides a gain in propagation distance, which is bounded by a sub-linear power law with respect to the elapsed time, in the referential of the moving cars. Combining these results, we thus obtain a complete picture of the way information propagates in vehicular networks on roads and highways, which may help designing and evaluating appropriate VANET routing protocols. We confirm our analytical results using simulations carried out in several environments (The One and Maple).
Message delivery delay analysis in VANETs with a bidirectional traffic model
2011 7th International Wireless Communications and Mobile Computing Conference, 2011
A VANET consists of vehicles equipped with on board units (OBUs) that can communicate with each other and the road side base stations. Due to the mobility and sparse distribution of vehicles, the delivery delay of messages in the VANET is mainly caused by the message transmissions between vehicles. The message delivery delay directly impacts the deployment of applications in VANET, and hence, an in-depth study of message delivery delay in the VANET is significant. In this paper, we focused on the investigation of the message delivery delay in the V2V stage with a bidirectional setting. The bidirectional traffic was modeled as a combination of two Poisson point processes. Based on the sub-additive ergodic theory, we found theoretically that the message delivery delay has a linear relationship with the message forwarding distance. Further, the upper bound of the coefficient of the linear relationship has an exponential polynomial relation with the density of vehicles on the road and decreases with the increment of the velocity of the traffic.
An analytical model of multihop connectivity of inter-vehicle communication systems
IEEE Transactions on Wireless Communications, 2010
Taking advantage of the proliferation of wireless communication devices, we could well develop Advanced Transportation Information Systems based on Inter-Vehicle Communication (IVC), in which drivers can have faster response to incidents and are able to communicate critical information in wake of disasters. Whether such IVC systems are feasible or not is highly related to the performance of multihop connectivity. Existing analytical studies of multihop connectivity, however, usually assume Poisson distribution of communication nodes or uniform distribution of vehicles on a road, and simulation-based studies are not suitable for real-time applications with computationally costly traffic simulators. In this paper, we present an analytical model for multihop connectivity of IVC in a traffic stream, in which positions of vehicles are all known through observations, traffic simulators, or traffic theories. After introducing Most-Forwarded-within-Range communication chains and node-and hope-related events, we derive a recursive model of node and hop probabilities and further define a number of performance measures of multihop connectivity. We then apply the model to study multihop connectivity of IVC in both uniform and non-uniform traffic and obtain results consistent with those in literature. The new analytical model is efficient without repeating traffic simulations while capable of capturing the impact of arbitrary distribution patterns of vehicles. Thus it is suitable for evaluating connectivity of IVC for different traffic congestion patterns and extended for studies of other situations.
Information propagation speed in bidirectional vehicular delay tolerant networks
2011 Proceedings IEEE INFOCOM, 2011
Ce rapportétudie la vitesse de propagation de l'information dans les réseaux DTN véhiculaires bidirectionnels, tels des automobiles sur une une autoroute. L'analyse présentée dans ce rapport montre qu'une transition de phase se produit concernant la vitesse de propagation de l'information, par rapportà la densité des véhicules dans chaque direction. Sous une certaine borne, l'information se propageà la vitesse des véhicules, alors qu'au dessus de cette borne, l'information se propage plus vite. Ce rapport donne l'expression exacte de cette borne et de la vitesse moyenne de propagation de l'information dans ce contexte.
A delay time analysis for multi-hop V2V communications over a linear VANET
IEEE Vehicular Networking Conference, 2009
Due to their highly dynamic nature, vehicular ad hoc networks (VANETs) are occasionally found difficult for their parameter optimization. Some attempts have been made to challenge the difficulty by modeling VANETs mathematically to predict parameter values successfully such as average cluster size and the lifetime of a path. Nevertheless, there have been no systematic approaches to analyze both node mobility and communication performances over a VANET by investigating its microspopic conditions. In this paper, we create a model for VANETs with basic natural assumptions. It mainly considers sparsely arranged vehicular nodes on a one-directional straight road, and assumes four hypotheses on the i) initial distribution of node density, ii) mobility, and iii) communication between nodes. Based on them, we will be able to find expressions for the exact delay time and delivery ratio, when a car sends a packet to k − 1 cars ahead. We will especially obtain a closed formula for the delivery ratio. We also compute the actual delay time and delivery ratio from available field data. Through the analysis, we observe that small values of the maximum wait time create sufficiently good performance even in a very sparse VANET.
Simulation of Car-to-Car Messaging: Analyzing the Impact on Road Traffic
13th IEEE International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems, 2005
Even though currently there is a lot of research going on in the field of short range wireless data communication between vehicles, inspired by the hope that this new technology can greatly improve traffic flow and prevent accidents, the effects have not yet been clearly analyzed. In this paper, we present one of the first approaches to gain insight into the benefits and drawbacks of deploying a socalled vehicular ad hoc network (VANET). In order to analyze such a complex system, a comprehensive simulation environment is needed. The requirements from the application side on such an environment are described and it is evaluated in how far existing simulation tools meet those requirements. Further, we are considering the traffic effects of a vehicle-to-vehicle traffic obstacle messaging application as one representative for the class of real-time traffic and safety information systems. For these kinds of applications, mainly traffic simulation and network simulation need to be combined. In addition, we discuss the integration of driver, vehicle and radio propagation models into a simulation environment that can be used to Analise the different kinds of VANET applications.