Showing papers on "Vehicular communication systems published in 2013"

LTE for vehicular networking: a survey

Abstract: A wide variety of applications for road safety and traffic efficiency are intended to answer the urgent call for smarter, greener, and safer mobility. Although IEEE 802.11p is considered the de facto standard for on-the-road communications, stakeholders have recently started to investigate the usability of LTE to support vehicular applications. In this article, related work and running standardization activities are scanned and critically discussed; strengths and weaknesses of LTE as an enabling technology for vehicular communications are analyzed; and open issues and critical design choices are highlighted to serve as guidelines for future research in this hot topic.

Performance Analysis and Enhancement of the DSRC for VANET's Safety Applications

Abstract: An analytical model for the reliability of a dedicated short-range communication (DSRC) control channel (CCH) to handle safety applications in vehicular ad hoc networks (VANETs) is proposed. Specifically, the model enables the determination of the probability of receiving status and safety messages from all vehicles within a transmitter's range and vehicles up to a certain distance, respectively. The proposed model is built based on a new mobility model that takes into account the vehicle's follow-on safety rule to derive accurately the relationship between the average vehicle speed and density. Moreover, the model takes into consideration 1) the impact of mobility on the density of vehicles around the transmitter, 2) the impact of the transmitter's and receiver's speeds on the system reliability, 3) the impact of channel fading by modeling the communication range as a random variable, and 4) the hidden terminal problem and transmission collisions from neighboring vehicles. It is shown that the current specifications of the DSRC may lead to severe performance degradation in dense and high-mobility conditions. Therefore, an adaptive algorithm is introduced to increase system reliability in terms of the probability of successful reception of the packet and the delay of emergency messages in a harsh vehicular environment. The proposed model and the enhancement algorithm are validated by simulation using realistic vehicular traces.

Performance and Reliability Analysis of IEEE 802.11p Safety Communication in a Highway Environment

Abstract: Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications are gaining increasing importance in vehicular applications. Dedicated short-range communication (DSRC) is a fundamental set of short-to-medium-range communication channels and a set of protocols and standards that are specifically designed for V2V and V2I communications. IEEE 802.11p is a protocol that has been standardized as the medium access control (MAC) layer of the DSRC standard. Due to the highly dynamic topology and low delay constraints in vehicular ad hoc networks (VANETs), direct (or one-hop) broadcast on the control channel (CCH) is an effective approach to inform the neighborhood of safety-related messages. The 802.11p enhanced distributed channel access (EDCA) mechanism allows four access categories (ACs) in a station for applications with different priorities according to their criticalities for the vehicle's safety. This paper focuses on the analysis of the 802.11p safety-critical broadcast on the CCH in a VANET environment and improves the existing work by taking several aspects into design consideration. Extensive performance evaluations based on the NS-2 simulator help to validate the accuracy of the proposed model and analyze the capabilities and limitations of the standard 802.11p broadcast on the CCH.

Cooperative Positioning for Vehicular Networks: Facts and Future

Abstract: Intelligent transportation systems (ITSs) are increasingly being considered to mitigate the impacts of road transportation, including road injuries, energy waste, and environmental pollution. Vehicular positioning is a fundamental part of many ITS applications. Although global navigation satellite systems (GNSSs), e.g., Global Positioning System (GPS), are applicable for navigation and fleet management, the accuracy and availability of GNSSs do not meet the requirements for some applications, including collision avoidance or lane-level positioning. Cooperative positioning (CP) based on vehicular communications is an approach to tackle these shortcomings. The applicability of vehicular CP techniques proposed in the literature is questionable due to viability issues, including internode distance estimation, which is an important part of many CP techniques. Conventional CP systems such as differential GPS (DGPS) and other augmentation systems are also effectively incapable of addressing the given ITS applications. In this paper, modern and conventional CP systems are discussed, and the viability of radio ranging/range rating and constraints of vehicular communications as main pieces of modern CP systems are investigated. The general performance boundaries for modern CP systems are explained, as is the gap existing between the positioning accuracy required for crucial ITS applications and what modern CP can provide. This is followed by introduction of a novel trend for vehicular CP research, which is a potential reliable solution using a modified concept of real-time kinematic (RTK) GPSs for vehicular environments.

Context-Aware Driver Behavior Detection System in Intelligent Transportation Systems

Abstract: Vehicular ad hoc networks (VANETs) have emerged as an application of mobile ad hoc networks (MANETs), which use dedicated short-range communication (DSRC) to allow vehicles in close proximity to communicate with each other or to communicate with roadside equipment. Applying wireless access technology in vehicular environments has led to the improvement of road safety and a reduction in the number of fatalities caused by road accidents through development of road safety applications and facilitation of information sharing between moving vehicles regarding the road. This paper focuses on developing a novel and nonintrusive driver behavior detection system using a context-aware system in VANETs to detect abnormal behaviors exhibited by drivers and to warn other vehicles on the road to prevent accidents from happening. A five-layer context-aware architecture is proposed, which is able to collect contextual information about the driving environment, to perform reasoning about certain and uncertain contextual information, and to react upon that information. A probabilistic model based on dynamic Bayesian networks (DBNs) in real time, inferring four types of driving behavior (normal, drunk, reckless, and fatigue) by combining contextual information about the driver, the vehicle, and the environment, is presented. The dynamic behavior model can capture the static and the temporal aspects related to the behavior of the driver, thus leading to robust and accurate behavior detection. The evaluation of behavior detection using synthetic data proves the validity of our model and the importance of including contextual information about the driver, the vehicle, and the environment.

Vehicular Communications Using DSRC: Challenges, Enhancements, and Evolution

Abstract: Dedicated Short-Range Communications (DSRC) has been designed to support vehicular communications. In the U.S., DSRC operates in the 5.9 GHz licensed spectrum band. Its physical (PHY) and medium access control (MAC) layers, defined in the IEEE 802.11p standard, are based on the IEEE 802.11 family of Wi-Fi standards. Vehicular communication environments differ significantly from the sparse and low-velocity nomadic use cases of a typical Wi-Fi deployment. Thus, there are many challenges to adapt Wi-Fi technologies to support the unique requirements of vehicular communications such as achieving high and reliable performance in highly mobile, often densely populated, and frequently non-line-of-sight environments. The automotive and the communications industries, academia, and governments around the world have been devoting tremendous efforts to address these challenges, and significant achievements have been made. Remaining challenges can be addressed by the future versions of DSRC. In this paper, we investigate the current technologies used by DSRC to support vehicle safety communications, analyze existing and possible DSRC performance enhancements that can be realized in the near term, and provide a few initial thoughts on the DSRC evolution path.

Moving cells: a promising solution to boost performance for vehicular users

Abstract: In future wireless networks, a significant number of users accessing wireless broadband will be vehicular (i.e., in public transportation vehicles like buses, trams, or trains). The Third Generation Partnership Project has started to investigate how to serve these vehicular users cost-effectively, and several solutions have been proposed. One promising solution is to deploy a moving relay node (MRN), on a public transportation vehicle that forms its own cell inside the vehicle to serve vehicular users. By proper antenna placement, an MRN can reduce or even eliminate the vehicular penetration loss that affects communication. Moreover, MRNs can exploit various smart antenna techniques and advanced signal processing schemes, as they are less limited by size and power than regular user equipment. However, there are also challenges in using MRNs, such as designing efficient interference management techniques as well as proper mobility management schemes to exploit the benefit of group handovers for vehicular UE devices served by the same MRN. Nevertheless, initial system-level evaluation results indicate that a dedicated MRN deployment shows great potential to improve the vehicular user experience, and thereby can potentially bring significant benefits to future wireless communication systems.

The Next Paradigm Shift: From Vehicular Networks to Vehicular Clouds

Abstract: This chapter contains sections titled: By Way of Motivation The Vehicular Model Vehicular Networks Cloud Computing Vehicular Clouds How are Vehicular Clouds Different? Feasible Instances of Vehicular Clouds More Application Scenarios Security and Privacy in Vehicular Clouds Key Management Research Challenges Architectures for Vehicular Clouds Resource Aggregation in Vehicular Clouds A Simulation Study of VC Future Work Where to From Here? References

Multichannel communications in vehicular Ad Hoc networks: a survey

Abstract: Vehicular ad hoc networks are the key to provisioning safety-critical and commercial services on the road. Multiple channels are assigned in the 5 GHz spectrum to support these services. In this article an overview of the multichannel architecture proposed by standardization bodies in the United States and Europe is presented. The main contribution is the identification of the open challenges for multichannel coordination, synchronization, and access. Discussions on related countermeasures, fully explored in neither the standards nor the scientific literature, aim to serve as guidelines for designers of future protocols and applications in vehicular environments.

Vehicular Networks for a Greener Environment: A Survey

Abstract: Researchers are looking for solutions that save the environment and money. Vehicular ad-hoc networks (VANETs) offer promising technology for safety communications. Thus, researchers try to integrate certain applications into existing research. The current survey critically examines the use of vehicular communication networks to provide green solutions. We discuss the current implementations of technology and provide a comparison from the communication perspective. This paper is meant to motivate researchers to investigate a new direction in which a network of vehicles is used to enhance total fuel and power consumption, gas emissions, and-as a result-budgets. Moreover, open issues and research directions that have only been slightly addressed, if at all, are discussed.

Cooperative vehicle-to-vehicle active safety testing under challenging conditions

Abstract: Cooperative vehicular communication systems are being developed to improve traffic safety and efficiency through the wireless exchange of information between vehicles and between vehicles and infrastructure units. The future deployment of cooperative active safety applications requires their prior extensive testing due to their critical nature and strict quality of service requirements. Such testing should consider challenging driving and communications conditions that could significantly impact the applications' effectiveness. In this context, this paper presents a cooperative communications testing platform implemented to evaluate the operation and effectiveness of cooperative active safety applications under challenging driving and communications conditions. The paper also reports the results of an extensive testing campaign that reveals potential limitations of cooperative technologies and applications, and discusses possible countermeasures to overcome the applications' effectiveness degradation under adverse operating conditions.

A Framework for Secure and Efficient Data Acquisition in Vehicular Ad Hoc Networks

Abstract: Intervehicular communication lies at the core of a number of industry and academic research initiatives that aim at enhancing the safety and efficiency of transportation systems. Vehicular ad hoc networks (VANETs) enable vehicles to communicate with each other and with roadside units (RSUs). Service-oriented vehicular networks are special types of VANETs that support diverse infrastructure-based commercial services, including Internet access, real-time traffic management, video streaming, and content distribution. Many forms of attacks against service-oriented VANETs that attempt to threaten their security have emerged. The success of data acquisition and delivery systems depends on their ability to defend against the different types of security and privacy attacks that exist in service-oriented VANETs. This paper introduces a system that takes advantage of the RSUs that are connected to the Internet and that provide various types of information to VANET users. We provide a suite of novel security and privacy mechanisms in our proposed system and evaluate its performance using the ns2 software. We show, by comparing its results to those of another system, its feasibility and efficiency.

Cars as roadside units: a self-organizing network solution

Abstract: Deploying roadside units, RSUs, for increasing the connectivity of vehicular ad hoc networks is deemed necessary for coping with the partial penetration of DSRC radios into the market in the initial stages of DSRC deployment. Several factors, including cost, complexity, existing systems, and lack of cooperation between government and private sectors, have impeded the deployment of RSUs. In this article, we propose to solve this formidable problem by using a biologically inspired self-organizing network approach whereby certain vehicles serve as RSUs. The proposed solution is based on designing local rules and the corresponding algorithms that implement them. Results show that the proposed approach can increase the message reachability and connectivity substantially.

ZOOM: Scaling the mobility for fast opportunistic forwarding in vehicular networks

Abstract: Vehicular networks consist of highly mobile vehicles communications, where connectivity is intermittent. Due to the distributed and highly dynamic nature of vehicular network, to minimize the end-to-end delay and the network traffic at the same time in data forwarding is very hard. Heuristic algorithms utilizing either contact-level or social-level scale of vehicular mobility have only one-sided view of the network and therefore are not optimal. In this paper, by analyzing three large sets of Global Positioning System (GPS) trace of more than ten thousand public vehicles, we find that pairwise contacts have strong temporal correlation. Furthermore, the contact graph of vehicles presents complex structure when aggregating the underlying contacts. In understanding the impact of both levels of mobility to the data forwarding, we propose an innovative scheme, named ZOOM, for fast opportunistic forwarding in vehicular networks, which automatically choose the most appropriate mobility information when deciding next data-relays in order to minimize the end-to-end delay while reducing the network traffic. Extensive trace-driven simulations demonstrate the efficacy of ZOOM design. On average, ZOOM can improve 30% performance gain comparing to the state-of-art algorithms.

A smart city framework for intelligent traffic system using VANET

Abstract: The total number of vehicles in the world has experienced a remarkable growth, increasing traffic density which results in more and more accidents. Therefore the manufactures, researchers and government is shifting focus towards improving the on road safety rather than improving the quality of the roads. The good development in the wireless technologies emerged various new type of networks, such as Vehicular Ad Hoc Network (VANET), which provides communication between vehicles themselves and between vehicles and road side units. Various new concepts such as smart cities and living labs [1] are introduced in the recent years where VANETs plays an important role. A survey of various Intelligent Traffic Systems (ITS) and various routing protocols with respect to our proposed scheme is described in this paper. It also introduces a new scheme consist of a smart city framework that transmit information about traffic conditions that will help the driver to take appropriate decisions. It consists of a warning message module composed of Intelligent Traffic Lights (ITLs) which provides information to the driver about current traffic conditions.

The Evolution of Connected Vehicle Technology: From Smart Drivers to Smart Cars to....Self-Driving Cars.

Abstract: In this article, the author discusses the evolution of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) technology, which promise to impact the travel scenes in the United States and Europe. The information technology that underlies intelligent transportation systems (ITS), global positioning system (GPS), and in-vehicle technologies now provides the framework for these connected-vehicle (CV) technologies. V2V technologies will allow roadway vehicles to communicate with each other, creating active safety systems that can prevent crashes and reduce traffic injuries and fatalities. The article describes the Connected Vehicle Safety Pilot Model Deployment Program, the world's largest real-world test of dedicated short-range communication (DSRC)-based connected vehicle communication technology. Other topics highlighted in this article include the National Highway Traffic Safety Administration (NHTSA)'s anticipated regulatory involvement in connected vehicle technology, the Maricopa County Department of Transportation's SMARTDrive Program, the international deployment of cooperative intelligent transportation systems between Europe and the United States, and connected vehicle technology developments in the European Union.

Introduction to Intelligent Systems in Traffic and Transportation

Abstract: Urban mobility is not only one of the pillars of modern economic systems, but also a key issue in the quest for equality of opportunity, once it can improve access to other services. Currently, however, there are a number of negative issues related to traffic, especially in mega-cities, such as economical issues (cost of opportunity caused by delays), environmental (externalities related to emissions of pollutants), and social (traffic accidents). Solutions to these issues are more and more closely tied to information and communication technology. Indeed, a search in the technical literature (using the keyword ``urban traffic" to filter out articles on data network traffic) retrieved the following number of articles (as of December 3, 2013): 9,443 (ACM Digital Library), 26,054 (Scopus), and 1,730,000 (Google Scholar). Moreover, articles listed in the ACM query relate to conferences as diverse as MobiCom, CHI, PADS, and AAMAS. This means that there is a big and diverse community of computer scientists and computer engineers who tackle research that is connected to the development of intelligent traffic and transportation systems. It is also possible to see that this community is growing, and that research projects are getting more and more interdisciplinary. To foster the cooperation among the involved communities, this book aims at giving a broad introduction into the basic but relevant concepts related to transportation systems, targeting researchers and practitioners from computer science and information technology. In addition, the second part of the book gives a panorama of some of the most exciting and newest technologies, originating in computer science and computer engineering, that are now being employed in projects related to car-to-car communication, interconnected vehicles, car navigation, platooning, crowd sensing and sensor networks, among others. This material will also be of interest to engineers and researchers from the traffic and transportation community.

A cluster based architecture for intersection collision avoidance using heterogeneous networks

Abstract: With the popularity of wireless devices, the possibility of implementing vehicular safety applications has been studied for years in the context of vehicular ad-hoc networks. Dedicated Short Range Communication (DSRC) is designed to serve the needs of vehicular safety applications. However, DSRC does not offer good enough coverage and range around intersections in urban areas for certain applications such as intersection collision avoidance. Considering these drawbacks, LTE, an advanced cellular communication technology, is proposed as an alternative to DSRC. One problem is LTE bandwidth capability to support regularly transmitted cooperative awareness messages. In this paper, we propose a cluster based architecture using both Wi-Fi and LTE channels to accomplish this task. In our architecture, Wi-Fi peer to peer channels are used for cluster formation while LTE channels are used for transmitting Cooperative Awareness Messages (CAMs). A clustering algorithm specifically designed for intersection collision avoidance service is proposed in this paper. In addition, a channel allocation algorithm is applied to reduce the interference of Wi-Fi channels between different clusters. Simulations show that CAM traffic can be efficiently supported in this architecture.

VANET-Enabled Eco-Friendly Road Characteristics-Aware Routing for Vehicular Traffic

Abstract: The lack of significant breakthroughs in terms of alternative energy sources has caused both fuel consumption and gas emissions to constantly increase. In this context, improving fuel efficiency and reducing emissions in the transportation sector is vital, as vehicles are one of the important contributors to air pollution. This paper introduces EcoTrec, a novel eco-friendly routing algorithm for vehicular traffic which considers road characteristics such as surface conditions and gradients, as well as existing traffic conditions to improve the fuel savings of vehicles and reduce gas emissions. EcoTrec makes use of the Vehicular Ad-hoc NETworks (VANET) both for collecting data from distributed vehicles and to disseminate information in aid of the routing algorithm. The algorithm calculates the fuel efficiency of various routes and then directs the vehicle to a fuel efficient route, while also avoiding flash crowding. Simulation-based tests showed that by using EcoTrec, fuel emissions were significantly reduced, when compared with existing state-of-the-art vehicular routing algorithms.

Performance of Vehicle-to-Vehicle Communication using IEEE 802.11p in Vehicular Ad-hoc Network Environment

Abstract: Traffic safety applications using vehicle-to-vehicle (V2V) communication is an emerging and promising area within the ITS environment. Many of these applications require real-time communication with high reliability. To meet a real-time deadline, timely and predictable access to the channel is paramount. The medium access method used in 802.11p, CSMA with collision avoidance, does not guarantee channel access before a finite deadline. The well-known property of CSMA is undesirable for critical communications scenarios. The simulation results reveal that a specific vehicle is forced to drop over 80% of its packets because no channel access was possible before the next message was generated. To overcome this problem, we propose to use STDMA for real-time data traffic between vehicles. The real- time properties of STDMA are investigated by means of the highway road simulation scenario, with promising results.

Enabling vehicular safety applications over LTE networks

Abstract: Advanced Driving Assistance Systems (ADAS) for improving vehicular safety are increasingly network based, with approaches that use vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communication. Most current proposals for V2V and V2I use DSRC and a dedicated infrastructure of road side units (RSUs) for the V2I scenarios. Here, the technical feasibility of an alternative architecture is explored, one that uses a combination of LTE cellular networks and servers near the edge of the LTE network. Compared with approaches based on DSRC and RSUs, this architecture exploits an infrastructure that is already largely deployed, but requires that technical challenges related to latency and scalability be addressed. This paper outlines an architecture that addresses these challenges and shows experimental results that demonstrate its effectiveness for vehicular safety applications. The approach combines resources near the network edge with broadcast-based data distribution to provide data freshness guarantees comparable to what can be achieved with DSRC for many applications. Experiments from the deployed LTE network and NS-3 simulations demonstrate that this approach is feasible, and show the benefits and limitations of the architecture.

VIP-WAVE: On the Feasibility of IP Communications in 802.11p Vehicular Networks

Abstract: Vehicular communication networks, such as the 802.11p and Wireless Access in Vehicular Environments (WAVE) technologies, are becoming a fundamental platform for providing real-time access to safety and entertainment information. In particular, infotainment applications and, consequently, IP-based communications, are key to leverage market penetration and deployment costs of the 802.11p/WAVE network. However, the operation and performance of IP in 802.11p/WAVE are still unclear as the WAVE standard guidelines for being IP compliant are rather minimal. This paper studies the 802.11p/WAVE standard and its limitations for the support of infrastructure-based IP applications, and proposes the Vehicular IP in WAVE (VIP-WAVE) framework. VIP-WAVE defines the IP configuration for extended and non-extended IP services, and a mobility management scheme supported by Proxy Mobile IPv6 over WAVE. It also exploits multi-hop communications to improve the network performance along roads with different levels of infrastructure presence. Furthermore, an analytical model considering mobility, handoff delays, collisions, and channel conditions is developed for evaluating the performance of IP communications in WAVE. Extensive simulations are performed to demonstrate the accuracy of our analytical model and the effectiveness of VIP-WAVE in making feasible the deployment of IP applications in the vehicular network.

Road traffic density estimation in vehicular networks

Abstract: Road traffic density estimation provides important information for road planning, intelligent road routing, road traffic control, vehicular network traffic scheduling, routing and dissemination. The ever increasing number of vehicles equipped with wireless communication capabilities provide new means to estimate the road traffic density more accurately and in real time than traditionally used techniques. In this paper, we consider the problem of road traffic density estimation where each vehicle estimates its local road traffic density using some simple measurements only, i.e. the number of neighboring vehicles. A maximum likelihood estimator of the traffic density is obtained based on a rigorous analysis of the joint distribution of the number of vehicles in each hop. Analysis is also performed on the accuracy of the estimation and the amount of neighborhood information required for an accurate road traffic density estimation. Simulations are performed which validate the accuracy and the robustness of the proposed density estimation algorithm.

Wireless Vehicular Networks for Car Collision Avoidance

Abstract: Wireless Vehicular Networks for Car Collision Avoidance focuses on the development of the ITS (Intelligent Transportation Systems) in order to minimize vehicular accidents. The book presents and analyses a range of concrete accident scenarios while examining the causes of vehicular collision and proposing countermeasures based on wireless vehicular networks. The book also describes the vehicular network standards and quality of service mechanisms focusing on improving critical dissemination of safety information. With recommendations on techniques and protocols to consider when improving road safety policies in order to minimize crashes and collision risks.

Context awareness beacon scheduling scheme for congestion control in vehicle to vehicle safety communication

Abstract: Vehicle safety applications based on vehicle to vehicle communication typically transmit safety-related beacons to all neighboring vehicles with high reliability and a strict timeline. However, due to high vehicle mobility, dynamic network topology and limited network resource, this periodic beaconing could lead to congestion in the communication network. Therefore, beacon transmission method has a special challenge to efficiently use the limited network resources to satisfy the requirements of safety applications. With this motivation, we propose a novel distributed beacon scheduling scheme referred to as the context awareness beacon scheduling (CABS) which is based on spatial context information dynamically scheduling the beacon by means of TDMA-like transmission. The proposed beacon scheduling scheme was evaluated using different traffic scenarios within both a realistic channel model and IEEE 802.11p PHY/MAC model in our simulation. The simulation results showed that the performance of the CABS scheme was better than periodic scheduling in terms of packet delivery ratio and channel access delay. Also, the CABS scheme satisfies the requirements of the safety applications.

Dynamic Traffic Control with Fairness and Throughput Optimization Using Vehicular Communications

Abstract: Traffic congestion in modern cities seriously affects our living quality and environments. Inefficient traffic management leads to fuel wastage in volume of billion gallons per year. In this paper, we propose a dynamic traffic control framework using vehicular communications and fine-grained information, such as turning intentions and lane positions of vehicles, to maximize traffic flows and provide fairness among traffic flows. With vehicular communications, the traffic controller at an intersection can collect all fine-grained information before vehicles pass the intersection. Our proposed signal scheduling algorithm considers the flows at all lanes, allocates more durations of green signs to those flows with higher passing rates, and also gives turns to those with lower passing rates for fairness provision. Simulation results show that the proposed framework outperforms existing works by significantly increasing the number of vehicles passing an intersection while keeping average waiting time low for vehicles on non-arterial roads. In addition, we discuss our implementation of an Zigbee-based prototype and experiences.

Methods and apparatus for communicating safety message information

Abstract: Various embodiments, relate to a communications system in which communications devices of users and communications devices of vehicular systems communicate safety messages through a cellular communications band or the DSRC (Dedicated short-range communications) vehicular communications band or a combination of both Various methods and apparatus are directed to communicating safety messages between vehicles and pedestrians/cyclists through the use of a cell phone, thus improving the impact of vehicular communications In some embodiments, at least some cell phones in a communications system includes both a DSRC communications capability and a cellular communications capability

Voronoi-based placement of road-side units to improve dynamic resource management in Vehicular Ad Hoc Networks

Abstract: Vehicular Ad-hoc Networks (VANETs) illustrate mobile P2P networks, which hold significant promise in improving traffic safety and alleviating traffic congestion. Reliable VANETbased services require dynamic resource management due to limited and often fluctuating network connectivity of VANETs that stem from the wireless and mobile nature of vehicleto-vehicle (V2V) communications. To address these needs, a collaboration with Road-Side Units (RSU) have been proposed to complement V2V communication by providing event and data brokering capability in the form of Vehicle-to-Infrastructure (V2I) communications. Deploying RSUs involves upfront investment and maintenance costs, and hence solutions are needed that maximize the benefit of RSUs by placing them effectively in accordance to existing and projected traffic density, and the types of services planned for VANETs. To address these challenges, this paper proposes a novel Voronoi diagram-based algorithm for the effective placement of RSUs using packet delay and loss as a criteria. This approach has two-fold advantages: a significant reduction in the number of RSUs required to cover a geographic region, and increase in the logical coverage area of each RSU irrespective of the dynamic vehicular traffic conditions thereby improving reliability of communications. This algorithm has been evaluated in the context of a road network and traffic conditions for an urban area. When compared with other baseline placement algorithms, communication reliability stemming from our Voronoi diagram-based placement algorithm results in less packet delay and lesser packet loss both of which are important to realize the different VANET-based services.