Multi-lane vehicle-to-vehicle networks with time-varying radio ranges: Information propagation speed properties (original) (raw)

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).

Information Dissemination Delay in Vehicle-to-Vehicle Communication Networks in a Traffic Stream

IEEE Transactions on Intelligent Transportation Systems, 2015

Vehicle-to-vehicle (V2V) communication networks, as one of the core components in connected vehicle systems, have been granted many promising applications to address traffic mobility, safety and sustainability. However, only a limited amount of work has been completed to understand the fundamental properties of information propagation in such systems, while comprehensively considers traffic and communication reality. Motivated by this view, this proposed research develops analytical formulations to estimate information propagation time delay via a V2V communication network formed on a one-way or two-way road segment with multiple lanes. Distinguished to previous efforts, the proposed study carefully involves several critical communication and traffic flow features in reality, such as wireless communication interference, intermittent information transmission, and dynamic traffic flow. Moreover, this study elaborately analyzes the interactions between information and traffic flow under sparse and congested traffic flow conditions. The numerical experiments based on Next-Generation Simulation (NGSIM) field data illustrate that the proposed analytical formulations are able to provide very good estimation, with the relative error less than 5%, for the information propagation time delay on a one-way or two-way road segment under various traffic conditions. The proposed work can be further extended to characterize information propagation time delay and coverage over local transportation networks.

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.

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.

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.

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.