An Efficient Data Dissemination Protocol with Roadside Parked Vehicles' Assistance in Vehicular Networks

Vehicular ad hoc network (VANET) is an emerging technology for the future intelligent transportation systems (ITS). How to design an efficient routing protocol for VANET is a challenging task due to the high mobility and uneven distribution of vehicles in urban areas. This paper proposes a backbone-based approach to providing the optimal inner-street relaying strategy. The virtual backbone is created distributively in each road segment based on the newly introduced stability index, which considers the link stability between vehicles and the mobility of vehicles. We also deploy the roadside unit (RSU) at intersections to determine the next path for forwarding data. The RSU gathers a global view of backbone vehicles on each road connected to the junction and analyzes the performance of the backbone as a basis of routing path selection. Simulation results show that the proposed protocol outperforms the conventional protocols in terms of packet delivery ratio and end-to-end delay.

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.

In wireless sensor networks, there have recently been studies on mobile sinks groups such as groups of soldiers on battlefields, which are characterized by geographically collective movement. Although the existing protocols for individual mobile sinks can support the mobile sinks groups, they suffer from high congestion and control overhead due to location updates by each sink in the groups. To solve the location update problem by individual sinks, a protocol, called M-Geocasting only updates the region information of the mobile sink groups to sources. However, since M-Geocasting uses the flooding within the group regions for data delivery to member sinks, it excessively consumes the energy of sensor nodes in the group region. Moreover, the flooding potentially causes broadcast storms within the group region when many events exist. Thus, in this paper, we propose an efficient data dissemination protocol which can avoid the flooding within the group region for supporting mobile sink group. The proposed protocol introduces a virtual pipe in the group region for data dissemination as data storage. In the proposed protocol, a source sends data to the pipe and member sinks retrieve data directly from the pipe. Simulation results show that the proposed protocol is superior to the existing protocols in terms of the energy consumption and the data delivery ratio.

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.

The vehicular adhoc networks (VANETs) is an integral part of the intelligent transportation system required for delivering safety and non-safety messages to vehicles in real-time via vehicle to vehicle and vehicle to everything communication modes. The purpose of VANETs is to provide efficient routing, message security, congestion-free traffic, and other services related to entertainment and comfortable journey. All these VANETs services, at the core, are related to efficient and secure data dissemination. In this paper, we have focused on clustering in VANETs for efficient data dissemination and resource sharing tasks. Considering the importance of fog computing for fast computing and processing, we have focused on clustering techniques in Fog-based VANET as well that can enhance the range of transmission and expand the number of available resources. This survey paper discusses the existing clustering techniques in VANETs scenario, cluster head selection parameters, the context-based techniques, and cluster performance parameters in VANETs.

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.

Road safety applications envisaged for vehicular ad hoc networks (VANETs) depend largely on the exchange of messages to deliver information to concerned vehicles. Safety applications as well as inherent VANET characteristics make data dissemination an essential service and a challenging task. We are developing a decentralized efficient solution for broadcast data dissemination through two game-theoretical mechanisms. Besides, VANETs can also include autonomous vehicles (AVs). AVs might represent a revolutionary new paradigm that can be a reality in our cities in the next few years. AVs do not need a driver to work; instead, they should copy a proper human behavior to adapt the driving according to the current circumstances, such as speed limit, pedestrian crossing street or wheather conditions. We will develop an AV software module including artificial intelligence (AI) techniques so that AVs can interact with the dynamic scenario throughout time. Finally, we also will include electrical vehicles (EV) in the VANET, so that special services such as finding and reserving an EV charging station place will be welcome. In addition, we are developing a multimetric geographic routing protocol for VANETs to transmit H.265 video (traffic accident, traffic state, commercial….) over VANETs.

Fog computing for vehicular Ad-hoc networks: paradigms, scenarios, and issues

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.

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.

Vehicular Ad Hoc Networks (VANETs) have emerged as an exciting research and application area. The envisioned applications, as well as some inherent VANET characteristics such as highly dynamic topology, frequently disconnected network, and different and dynamic network density, make data dissemination a challenging task in these networks. Several approaches for data dissemination in VANETs have been recently proposed in the literature. However, more work needs to be done since most of the proposed solutions do not effectively address some or all of the main challenges in these scenarios such as the broadcast storm, network partition and temporal network fragmentation. In this paper, we provide a comprehensive and critical review of proposed techniques for data dissemination in VANETs and identify the main challenges in this area. For this, we first define suitable criteria to classify and organize some of the existing solutions. Next we identify and discuss some open issues and conclude with possible future research directions.

Vehicular Ad hoc NETworks (VANET) has been well studied for a long time as a means to exchange information among moving vehicles. As vehicular networks do not always have connected paths, vehicular networks can be regarded as a kind of delay-tolerant networks (DTNs) when the density of vehicles is not high enough. In this case, packet delivery ratio degrades significantly so that reliability of networks as an information infrastructure is hardly held. Past studies such as SADV (Static-node Assisted Data dissemination protocol for Vehicular networks) and RDV (Reliable Distance-Vector routing) showed that the assistance of low-cost unwired static nodes located at intersections, which work as routers to provide distance-vector or link-state routing functions, significantly improves the communication performance. However, they still have problems: SADV does not provide high-enough delivery ratio and RDV suffers from traffic concentration on the shortest paths. In this paper, we propose MP-RDV (Multi-Path RDV) by extending RDV with multiple paths utilization to improve performance against both of those problems. In addition, we apply a delay routing metric, which is one of the major metrics in this field, to RDV to compare performance with the traffic-volume metric, which is a built-in metric of RDV. Evaluation results show that MP-RDV achieves high load-balancing performance, larger network capacity, lower delivery delay, and higher fault tolerance against topology changes compared to RDV. As for routing metrics, we showed that the traffic-volume metric is better than the delay one in RDV because delay measurement is less stable against traffic fluctuation.

A new concept such as smart city was introduced in the last years where the Intelligent Transportation system (ITS ) plays a critical role to provide road safety and manage Vehicular Ad Hoc Networks (VANETs) traffic. Nevertheless, VANETs have significant constraints like nodes high mobility, intermittent connectivity, variable network density and heterogeneity. However, the different types of traffic, the different Quality of Service requirements, the need to exchange mobile data, multi-services and data diversity leads mainly to load and time constraints in this specific and stringent type of networks. The main characteristic of this kind of networks is the very changing topology that poses supplementary constraints and makes achieving QoS constraints a very challenging task. In VANET network the vehicle generated traffic will be transferred to the data center from road side unit to the base station by using Long Term Evolution (LTE) in an urban area. Despite LTE has a larger system capacity and it provides a higher transmission speed, the network performance is affected by the implemented scheduling algorithm. In this context, we study the efficiency of LTE scheduler algorithms such as Proportional Fairness, Round Robin, Priority Set Scheduler, Maximum Throughput Scheduler and Throughput to Average Scheduler and Blind Equal Throughput mainly at the road side unit using Network Simulator 3(NS3) to determinate the most suitable scheduler for VANET traffic. Results demonstrate that the round robin algorithm is more effective for volumetric VANET traffic in terms of throughput, delay, packet loss rate and fairness.

Vehicular ad hoc networks (VANETs) are a special form of wireless networks made by vehicles communicating among themselves on roads. The conventional routing protocols proposed for mobile ad hoc networks (MANETs) work poorly in VANETs. As communication links break more frequently in VANETs than in MANETs, the routing reliability of such highly dynamic networks needs to be paid special attention. To date, very little research has focused on the routing reliability of VANETs on highways. In this paper, we use the evolving graph theory to model the VANET communication graph on a highway. The extended evolving graph helps capture the evolving characteristics of the vehicular network topology and determines the reliable routes preemptively. This paper is the first to propose an evolving graph-based reliable routing scheme for VANETs to facilitate quality-of-service (QoS) support in the routing process. A new algorithm is developed to find the most reliable route in the VANET evolving graph from the source to the destination. We demonstrate, through the simulation results, that our proposed scheme significantly outperforms the related protocols in the literature.

Vehicular Ad hoc Network (VANET) has been gaining the attention from the academic and industry communities due to the promising applications in road safety, traffic management and passenger comfort. However, the short vehicle-to-vehicle (V2V) communication range and the nature of vehicle mobility impose many challenges in packet routing and, accordingly, infrastructure-based applications, e.g., Internet access. For more reliable communication, automobile manufacturers have started the investigation to deploy cellular networks, such as LTE, to support in-car Internet access. In addition to the high communication cost to the end-user, using centric cellular networks for vehicular communication applications causes data explosion and network overload. A feasible solution is using VANETs for mobile data offloading when connectivity to infrastructure is guaranteed, which requires an efficient routing protocol with global connectivity awareness. In this paper, we propose a novel infrastructure-based, dynamic, and connectivity-aware routing protocol, iCARII, to enable infotainment applications and Internet access in an urban environment. iCARII aims to improve VANETs routing performance by enabling selecting roads with guaranteed connectivity and reduced delivery delay. Detailed analysis and simulation-based evaluations of iCARII demonstrate the significant improvement of VANET performance in terms of packet delivery ratio and end-to-end delay with a negligible cost of routing overhead.