Data dissemination in vehicular networks: Challenges, solutions, and future perspectives

VANETs (vehicular ad hoc networks) are emerging as a new network environment for intelligent transportation systems. Many of the applications built for VANETs will depend on the data push communication model, where information is disseminated to a group of vehicles. In this paper, we present a formal model of data dissemination in VANETs and study how VANET characteristics, specifically the bidirectional mobility on well defined paths, affects the performance of data dissemination. We study the data push model in the context of TrafficView, a system we have implemented to disseminate information about the vehicles on the road. Traffic data could be disseminated using vehicles moving on the same direction, vehicles moving in the opposite direction, or vehicles moving in both directions. Our analysis as well as simulation results show that dissemination using only vehicles in the opposite direction increases the data dissemination performance significantly

A Vehicular Ad Hoc Network (VANET) is a subclass of Mobile Ad Hoc Networks, which provides wireless communication among vehicles as well as between vehicles and roadside units. Providing safety, traffic efficiency and user comfort for drivers and passengers are promising goals of these networks. To reach these goals many envisaged applications for VANETs will rely on data dissemination, turning this task into an essential service. However, due to some inherent characteristics of VANETs, such as intermittent connectivity, highly dynamic topology, and diverse network densities, data dissemination is a challenging activity in this kind of network. Although data dissemination has been extensively studied in the literature, existing solutions do not effectively address the broadcast storm and network partition problems when considered together. To deal with both problems, we propose a network partition-aware geographical data dissemination protocol, which eliminates the broadcast storm and maximizes the data dissemination capability across network partitions with short delays and low overhead. The proposed algorithm is able to autonomically adjust message transmissions in the network. Simulation results show that our proposed approach provides good efficiency with respect to the coverage of event processing, delay and overhead.

Multihop data dissemination in vehicular ad hoc networks (VANETs) is very important for the realization of collision avoidance systems and many other interesting applications. However, designing an efficient data dissemination protocol for VANETs has been a challenging issue due to vehicle movements, limited wireless resources, and the lossy characteristics of wireless communication. In this paper, we propose a protocol that can provide a lightweight and reliable solution for data dissemination in VANETs. The protocol employs dynamically generated backbone vehicles to disseminate broadcast packets to reduce the MAC-layer contention time at each node while maintaining a high packet dissemination ratio by taking into account vehicle movement dynamics and the link quality between vehicles for the backbone selection. The protocol also uses network coding to reduce the protocol overhead and to improve the packet reception probability as compared with conventional approaches. We use theoretical analysis and computer simulations to show the advantage of the proposed protocol over other existing alternatives.

With the growth of large urban centers, some problems arise and solutions must be sought to contain them. In this context, traffic congestion is one such problem, where road infrastructure does not follow the high growth in the number of vehicles. Traffic Management Systems (TMS) arise to mitigate traffic-related problems, with automatic detection of slow roadways and vehicle rerouting to avoid such routes. Such applications are supported by the Vehicular Ad hoc NETworks (VANETs), where traffic information are disseminated between the vehicles or central server, and thus the better decisions about traffic management can be made. However, the data dissemination in VANETs is a challenging task, due to the short-range communication and high node mobility. Thus, this paper introduces a protocol for Data Dissemination based on Metrics of Complex Networks, called CRONOS. It provides data dissemination of traffic data with low overhead and high coverage. Simulation results show that CRONOS reduced the number of transmissions by 95%, the congestion time by 48.95%, and travel time by 18.11% for a TMS application.

Vehicular ad-hoc networks (VANETs) aim to increase the safety of passengers by making information available beyond the driver’s knowledge. The challenging properties of VANETs such as their dynamic behavior and intermittently connected feature need to be considered when designing a reliable communication protocol in a VANET. In this study, we propose an epidemic and density adaptive protocol for data dissemination in vehicular networks, namely EpiDOL, which utilizes the opposite lane capacity with novel probability functions. We evaluate the performance in terms of end-to-end delay, throughput, overhead and usage ratio of the opposite lane under different vehicular traffic densities via realistic simulations based on SUMO traces in ns-3 simulator. We found out that EpiDOL achieves more than 90% throughput in low densities, and without any additional load to the network 75% throughput in high densities. In terms of throughput EpiDOL outperforms the Edge-Aware and DV-CAST protocols 10% and 40% respectively.

Vehicular Ad-Hoc Networks (VANETs) are a fast growing technology that many governments and automobile manufacturers are investing in to provide not only safer and more secure roads, but also informational and entertainment-based applications for drivers. The applications developed for VANETs can be classified into multiple categories (safety, informational, entertainment). Most VANET applications, regardless of their category, depend on having certain vehicular data (vehicular speed, X position and Y position) available. Although these applications appear to use the same vehicular data, the characteristics of this data (i.e., amount, accuracy, and update rate) will vary based on the application category. For example, safety applications need an accurate version of the vehicular data with high frequency, but over short distances. Informational applications relax the data frequency constraint as they need the vehicular data to be reasonably accurate with less frequency, but over longer distances. If each of these applications shares the vehicular data with only its peers using its own mechanism, this behavior will not only introduce redundant functionalities (sending, receiving, processing, etc.) for handling the same data, but also wastefully consume the bandwidth by broadcasting the same data multiple times. Despite the differences in the data characteristics needed by each application, this data can be still shared. Vehicular networks introduce the potential for many co-existing applications. If we do not address the problem of data redundancy early, it may hinder the deployment and usefulness of many of these applications. Therefore, we developed a framework, cluster-based accurate syntactic compression of aggregated data in VANETs (CASCADE), for efficiently aggregating and disseminating commonly-used vehicular data. CASCADE is architccted as a layer that provides applications with a customized version of the vehicular data, based on parameters that each application registers with CASCADE. Additionally, the framework performs the common data handling functionalities (sending, receiving, aggregating, etc.) needed by the applications. This dissertation makes the following contributions: (1) a lossless data compression technique based on differential coding that is tailored for the characteristics of vehicular data; (2) a syntactic data aggregation mechanism that can represent the vehicular data in a 1.5 km area in one IEEE 802.11 frame; (3) a light-weight position verification technique that quickly detects false data with very low false positives; (4) a probabilistic data dissemination technique that alleviates the spatial broadcast storm problem and effectively uses the bandwidth to disseminate data to distant areas in a short amount of time in addition to having less redundancy and more coverage than other techniques. (5) a mechanism for recovering from the communication discontinuity problem in short time based on the traffic density in the opposite direction; (6) an investigation of the possible data structures for representing the vehicular data in a searchable format; (7) a parametric mechanism for matching the vehicular data and providing a customized version of the data that satisfies certain characteristics based on the parameter value. CASCADE through its four major components, local view, extended view, data security and data dissemination, provides an efficient solution for the problem of scalability for VANET applications.

Vehicular Ad hoc Networks (VANETs) have become a cornerstone component of Intelligent Transportation Systems (ITS). VANET applications present a huge potential for improving road safety and travel comfort, hence the growing interest of both academia and industry. The main advantage of VANETs is its ad hoc nature which does not require fixed infrastructure or centralized administration. However, designing scalable information dissemination techniques for VANET applications remains a challenging task due to the inherent nature of such highly dynamic environments. Existing dissemination techniques often resort to simulation for performance evaluation and there are only few studies that offer mathematical modeling. In this paper we provide a comparative study of existing performance modeling approaches for data dissemination techniques designed for different VANET applications.

For improving the traffic safety in intelligent transportation systems, vehicles that are formed by Vehicular Ad-hoc Networks (VANETs) conventionally disseminate warning messages to their nearby vehicles as soon as a dangerous situation occurs. However, the major challenge in VANETs is to develop an efficient data dissemination protocol for tackling the broadcast storm and network partition problems. In this paper, we propose an Adaptive Beacon-based Data Dissemination (ABDDis) scheme to deal with these problems using only local one-hop neighbor information. The ABDDis scheme features a novel mechanism to adaptively adjust the beacon interval to reduce the channel load while maintaining the correct information about nearby vehicles. Additionally, a novel store-carry-forward (SCF) mechanism is proposed to overcome the network partition problem. The performance of the ABDDis scheme is evaluated in the Veins simulation framework that provides a bidirectional coupling between the network simulator OMNeT++ and the traffic simulator SUMO. The simulation result shows that the ABDDis scheme significantly mitigates the broadcast storm compared to other schemes and maintains a good coverage across various traffic densities. Moreover, the ABDDis scheme shows its robustness by being able to tolerate reasonable GPS drift.

Vehicular ad-hoc networks are a promising type of networks that allows the communication between vehicles with the goal to promote safe and efficient traffic. During the trips, vehicles can communicate with each other and with other networks by interacting with them and with the cell phone network. In VANETs, data dissemination is a general task required by many services, which consists of the delivery of data messages to a group of vehicles. In this type of communication, the knowledge of the interactions among vehicles can help to improve the performance of data dissemination. Thus, in this work, we propose the TBD (Trajectory Based Dissemination), a solution that transmits the information on the network according to the density of vehicles in the path from the source to the region of interest. Simulation results evaluated in scenarios of various densities have shown that it is possible to reduce the number of messages transmitted with a high delivery ratio.

In view to reduce accident risks and improve safety on public roads, the vehicular Ad hoc network (VANET) standard was developed to enable inter-vehicular communication and facilitate safety message exchange among the involved nodes. Moreover, a successful message exchange can only be possible if the transmission medium is collision free. Under the Intelligent Transportation System (ITS), the cooperative Awareness messages (CAM) have to be transmitted at the rate of 10 Hz as per standard. To account for congestion management, the Distributed Congestion Control (DCC) mechanism was proposed. However, under higher node density, the DDC becomes inefficient and dramatically contribute to the deterioration of the VANET environment. The present work proposes a Dynamic Broadcast Storm Mitigation Algorithm (DBSMA) which can be used to combat the broadcast storm problem in a Vehicular Network (VN). Results from several simulations confirmed that the DBSMA has a potentiality to conquer the effect of broadcast storm by offering more than 130% improved efficiency against the DCC approach. Other advantage of the DBSMA is that it is very simple to compute and easy to implement.

SummaryThe recent breakthroughs in the automobile industries and telecommunication technologies along with the exceptional multimodal mobility services brought focus on intelligent transportation system (ITS), of which vehicular ad hoc networks (VANETs) gain much more attention. The distinctive features of software‐defined networking (SDN) leverages the vehicular networks by its state of the centralized art having a comprehensive view of the network. Its potential to bring the flexibility, programmability and other extensive advancements to vehicular networks has set the stage for a novel networking paradigm termed as software‐defined vehicular networks (SDVNs). Many researchers have demonstrated the SDN‐based VANETs with the various configuration of the SDN components in VANET architecture. However, a compilation of the work on the SDN‐based VANET system as a whole, incorporating its architecture, use‐cases, and opportunities, is still inadequate. We start with the summary of the recent studies that exist on the SDVNs, followed by the comprehensive explanation of its components. Next, we present the taxonomy of SDVN based on the architecture modes, protocols, access technologies, and opportunities with trending technologies. Finally, we highlight the challenges, open research issues, and future research directions.

Data dissemination is a challenging problem in vehicular ad hoc networks (VANETs) due to the characteristics of VANETs such as highly dynamic topology, intermittent connectivity, and the road-constrained mobility. Observed from the fact that on-street parking is a common phenomenon in the city, the parked vehicles at roadside can also contribute their resources to the communications in network. In this paper, an efficient data dissemination protocol (EDP) for VANETS is proposed. Different from the existing works which consider mainly mobile vehicles or some expensive roadside infrastructure, EDP leverages the resources of parked vehicles at roadside to help in forwarding data. EDP groups the parked vehicles at roadside into a cluster, which buffers and relays data from mobile vehicles and manages the duplicates of data. Simulation results based on a real city map show that EDP achieves a higher delivery ratio and lower delivery delay.

Vehicular networks often consist of computational devices that collect data representing the external environment (e.g., road traffic volume, terrain conditions, and vehicle tracking). The data collected is prone to errors for two reasons: first, the processing algorithms in devices often have only limited capabilities that result in a fuzzy and imprecise representation of the external datum; second, some of the devices may be maliciously faulty mis-reporting the external datum. In such a setting, replicating the devices and voting on the environment data collected by them enhances the trust-worthiness of data reported to the application. The paper describes a cooperation mechanism that embodies two complementary functions: replication of devices and voting among devices. Device-level cooperation is realized using a tree-structured overlay set up over a vehicular network, in which the root node is attached to a data dissemination station and the leaf nodes are attached to the data collection devices in different geographic regions. Voting among the data collected is carried out at the leaf nodes whereupon a sanitized data propagates up the tree towards the root. An intermediate node may also carry out aggregation functions on the data arriving from its downstream tree segments and then forward the aggregated data upstream. The paper describes the voting-based data collection and dissemination as a middleware service.

Industrial Internet of Things (IIoT) is the other name of industrial Internet. It integrates a variety of existing industrial automation technologies with computing, machine learning, and communication technologies. Vehicular ad hoc network, an application of IIoT, is a self‐organized network of vehicles which tends to provide improved road safety, diminished traffic congestion, and ultimate comfort to the travellers. In VANETs, vehicles exchange data with each other directly or through roadside units (RSUs). Data dissemination in VANETs experiences numerous challenging issues including broadcast storm, network partitions, intermittent connectivity between vehicles, and limited bandwidth. In literature, various data dissemination schemes are proposed. However, most of these schemes are designed for either urban or highway VANET scenarios and evaluated under sparse or dense traffic conditions. Moreover, these schemes do not effectively overcome the aforementioned issues simultaneously. In this paper, we present a new data dissemination protocol for VANETs, which disseminates the emergency messages in different scenarios under varying traffic conditions. During dense traffic conditions, DDP4V employs the segmentation of transmission region of a vehicle in order to select the most appropriate next forwarding vehicle (NFV). Accordingly, it divides the transmission region of a vehicle in three distinct segments and selects vehicle(s) inside the highest priority segment to forward the message to all neighbour vehicles, whereas it also uses implicit acknowledgements for guaranteed message delivery during sparse traffic Conditions. Simulation results show that DDP4V protocol outperforms the other existing related protocols in terms of coverage, network overhead, collision, and end‐to‐end delay.

We consider the problem of data dissemination in vehicular networks. Our main goal is to compare the application-level performance of fully distributed and centralized data dissemination approaches in the context of traffic advisory systems. Vehicular networks are emerging as a new distributed system environment with myriad promising applications. Wirelessly-connected, GPS-equipped vehicles can be used, for instance, as probes for traffic advisory or pavement condition information services with significant improvements in cost, coverage and accuracy. There is an ongoing discussion on the pros and cons of alternative approaches to data distribution for these applications. Proposed centralized, or infrastructure-based, models rely on road-side equipment to upload information to a central location for later use. Distributed approaches take advantage of the direct exchanges between participating vehicles to achieve higher scalability at the potential cost of data consistency. While distributed solutions can significantly reduce infrastructures' deployment and maintenance costs, it is unclear what the impact of "imprecise" information is to an application or what level of adoption is needed for this model to be effective. This paper investigates the inherent trade-offs in the adoption of distributed or centralized approaches to a traffic advisory service, a commonly proposed application. We based our analysis on a measurements study of signal propagation in urban settings and an extensive simulation-based experimentation in the Chicago road network.