On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case

One of the most challenging fields in vehicular communications has been the experimental assessment of protocols and novel technologies. Researchers usually tend to simulate vehicular scenarios and/or partially validate new contributions in the area by using constrained testbeds and carrying out minor tests. In this line, the present work reviews the issues that pioneers in the area of vehicular communications and, in general, in telematics, have to deal with if they want to perform a good evaluation campaign by real testing. The key needs for a good experimental evaluation is the use of proper software tools for gathering testing data, post-processing and generating relevant figures of merit and, finally, properly showing the most important results. For this reason, a key contribution of this paper is the presentation of an evaluation environment called AnaVANET, which covers the previous needs. By using this tool and presenting a reference case of study, a generic testing methodology is described and applied. This way, the usage of the IPv6 protocol over a vehicle-to-vehicle routing protocol, and supporting IETF-based network mobility, is tested at the same time the main features of the AnaVANET system are presented. This work contributes in laying the foundations for a proper experimental evaluation of vehicular networks and will be useful for many researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems, 201

SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS

A finales de los años noventa, y al comienzo del nuevo milenio, las redes inalámbricas han evolucionado bastante, pasando de ser sólo una tecnología prometedora para convertirse en un requisito para las actividades cotidianas en las sociedades desarrolladas. La infraestructura de transporte también ha evolucionado, ofreciendo comunicación a bordo para mejorar la seguridad vial y el acceso a contenidos de información y entretenimiento. Los requisitos de los usuarios finales se han hecho dependientes de la tecnología, lo que significa que sus necesidades de conectividad han aumentado debido a los diversos requisitos de las aplicaciones que se ejecutan en sus dispositivos móviles, tales como tabletas, teléfonos inteligentes, ordenadores portátiles o incluso ordenadores de abordo (On-Board Units (OBUs)) dentro de los vehículos. Para cumplir con dichos requisitos de conectividad, y teniendo en cuenta las diferentes redes inalámbricas disponibles, es necesario adoptar técnicas de Vertical Handover (VHO) para cambiar de red de forma transparente y sin necesidad de intervención del usuario. El objetivo de esta tesis es desarrollar algoritmos de decisión (Vertical Handover Decision Algorithms (VHDAs)) eficientes y escalables, optimizados para el contexto de las redes vehiculares. En ese sentido se ha propuesto, desarrollado y probado diferentes algoritmos de decisión basados en la infraestructura disponible en las actuales, y probablemente en las futuras, redes inalámbricas y redes vehiculares. Para ello se han combinado diferentes técnicas, métodos computacionales y modelos matemáticos, con el fin de garantizar una conectividad apropiada, y realizando el handover hacia las redes más adecuadas de manera a cumplir tanto con los requisitos de los usuarios como los requisitos de las aplicaciones. Con el fin de evaluar el contexto, se han utilizado diferentes herramientas para obtener información variada, como la disponibilidad de la red, el estado de la red, la geolocalizaciónMárquez Barja, JM. (2012). SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17869Palanci

Dynamic wireless mobile framework for distributed collaborative real-time information generation and control systems

Intelligent Transportation Systems (ITS) have only recently discovered the exciting possibilities in the nomadic and ubiquitous computing space to build a new generation of information systems by allowing the vehicle to act both as a carrier and consumer of wireless (and thus omnipresent) information. Wide deployment of such ITS systems may eventually allow for more dynamic and efficient transportation systems, which can contribute in several ways towards greater economic growth whilst respecting environmental sustainability. A great number of researchers have dedicated considerable time and resources to tackling traffic related issues by utilising the new wireless capabilities enabled by ITS; such initiatives cover a wide range of applications such as safety, knowledge sharing and infotainment. Indicative of the extent of such efforts is the plethora of research projects initiated by many national and multi-national organisations such as the EU Framework Programme for Research and Technological Development. To achieve their goals, proposed solutions from such organisations depend on the development and deployment of intelligent wireless mobile communication systems, where data dissemination issues make the prospect of efficient and effective communication a challenging proposition. Presently, Car-to-Car and Car-to-Infrastructure communications are two distinct avenues that make possible efficient and reliable delivery of messages via direct radio links in traffic areas. In all cases, high quality of communication performance is desirable for a communication system composed mostly of roaming participants; such a system needs to be dynamic, flexible and infrastructure-less. Consequently, Mobile Ad hoc Network (MANET)-based networks are a natural fit to ITS

VANET Applications: Hot Use Cases

Current challenges of car manufacturers are to make roads safe, to achieve free flowing traffic with few congestions, and to reduce pollution by an effective fuel use. To reach these goals, many improvements are performed in-car, but more and more approaches rely on connected cars with communication capabilities between cars, with an infrastructure, or with IoT devices. Monitoring and coordinating vehicles allow then to compute intelligent ways of transportation. Connected cars have introduced a new way of thinking cars - not only as a mean for a driver to go from A to B, but as smart cars - a user extension like the smartphone today. In this report, we introduce concepts and specific vocabulary in order to classify current innovations or ideas on the emerging topic of smart car. We present a graphical categorization showing this evolution in function of the societal evolution. Different perspectives are adopted: a vehicle-centric view, a vehicle-network view, and a user-centric view; described by simple and complex use-cases and illustrated by a list of emerging and current projects from the academic and industrial worlds. We identified an empty space in innovation between the user and his car: paradoxically even if they are both in interaction, they are separated through different application uses. Future challenge is to interlace social concerns of the user within an intelligent and efficient driving

Performance evaluation of realistic scenarios for vehicular ad hoc networks with VanetMobiSim and NS2

Català: En els darrers anys, el considerable creixement del sector dels serveis mòbils arreu del món es certament el major fenòmen al camp de les telecomunicaciones. Les tecnologies inalàmbriques han conduït al desenvolupament de nous sistemes de comunicació y serveis multimèdia. Degut al constant creixement del mercat automobilístic juntament amb la creixent demanda de la seguretat viària ha nascut un nou concepte al camp de les comunicaciones: les xarxes entre vehicles (VANETs). A les VANETs, cada vehicle pot actuar com a router o node, establint connexions entre vehicles propers o amb infraestructura a la carretera. Les VANET estan rebent més atenció del govern i de la indústria automobilística degut a l'àmplia varietat d'aplicacions y serveis que poden oferir, tal com sistemes de seguretet viària assistència a la carretera i accès a Internet. No obstant, el disseny i l'implementació de VANETs és una àrea d'investigació àmplia i complexa tal i com podem percebre, sabent que durant els darrers anys la comunitat investigadora s'ha centrat en l'estudi d'aquestes xarxes. Bàsicament, el nostre projecte està dividit en dues parts principals: Primerament, hem dut a terme una recerca relacionada amb l'estat actual de les VANET avui en dia, amb l'objectiu d'identificar els generadors de moviment i els simuladors de xarxes més apropiats i recomenats a la literatura. En segon lloc, hem decidit utilitzar el VanetMobiSim [80], com a generador de moviment degut a la seva varietat de models de movilitat que es poden testejar, i el NS2 [63] com a simulador de xarxes per ser un dels més utilitzats per molts autors a més de la seva compatibilitat amb el VanetMobiSim. Amb l'ús d'aquestes eines, VanetMobiSim i NS2, hem dut a terme una avaluació profunda de les prestacions de les VANET en diversos escenaris reals, assignant valors diferents a paràmetres tals com el nombre de nodes, la velocitat i el model de propagació.Castellano: En los últimos años, el considerable crecimiento del sector de los servicios móviles alrededor del mundo es con certeza el mayor fenómeno en el campo de las telecomunicaciones. Las tecnologías inalámbricas han conducido al desarrollo de nuevos sistemas de comunicación y servicios multimedia. Debido al constante crecimiento del mercado automovilístico y la creciente demanda en seguridad vial ha nacido un nuevo concepto en el campo de las comunicaciones: las redes entre vehículos (VANETs). En ellas, cada vehículo actúa como router, estableciendo conexiones entre vehículos cercanos o con infraestructura en la carretera. Las VANET estan recibiendo más atención del gobierno y de la industria automovilística debido a la amplia variedad de aplicaciones y servicios que puede ofrecer, tales como sistemas de seguridad vial, asistencia en carretera y acceso a Internet. Sin embargo, el diseño e implementación de las VANET es un area de investigación amplia y compleja, tal y como podemos percibir, sabiendo que durante los últimos años la comunidad investigadora se ha centrado en el estudio de estas redes. Básicamente, nuestro proyecto está dividido en dos partes principales: Primeramente, hemos llevado a cabo una búsqueda relacionada con el estado de arte de las VANET hoy en día, con el objetivo de identificar los generadores de movimiento i los simuladores de redes más apropiados i recomendados en la literatura. En segundo lugar, hemos decidido utilizar el VanetMobiSim [80], como generador de movimiento debido a la alta variedad de modelos de mobilidad que que se pueden testear, y el NS2 [63] como simulador de redes por ser uno de los más utilizados per muchos autores además de su compatibilidad con el VanetMobiSim. Con el uso de estas herramientas, hemos llevado a cabo una evaluación profunda de las prestaciones de las VANET en varios escenarios reales, asignando valores diferentes a parámetros tales como el número de nodos, la velocidad y el modelo de propagación.English: Over recent years, the considerable mobile services sector growth around the world was certainly the major phenomenon in the telecommunications field. Wireless technology has led to the development of new communications systems and multimedia services. Due to the continued growth of the vehicular industry and the increasing demand of road safety, a new concept in the communications field was born: vehicular networks (VANETs). In VANETs, each vehicle could act as router or node, establishing connections among nearby vehicles or with roadside infrastructure. VANETs are receiving more attention from governments and car manufacturers due to the wide variety of applications and services they can provide such as road safety systems, car assistance and Internet acces. However, designing and implementing VANETs is a complex and wide area of research as we can notice, knowing that in the last years the research and development community has focused on the study of such networks. Basically, our project is divided in two main parts: Firstly, we made a state of art related to the actual state of VANETs nowadays in order to find the most appropiate and recommended mobility generator and network simulator reported in the literature. Secondly, we decided to use VanetMobiSim [80], as a mobility generator due to its variety mobility models that could be tested, and NS2 [63] as a network simulator for being one of the most used by many authors and also due to its compatibilty with VanetMobiSim. Using these tools, VanetMobiSim and NS2, we carried out a deep performance evaluation of VANETs in several realistic scenarios, giving different values to parameters such as the number of nodes, speed and the propagation model

Investigate the Development of a Wireless Flight Test System

This thesis describes the development and fight testing of a wireless flight test data acquisition system based on the IEEE 802.11 a/b/g protocols using low cost Commercial-Off-The-Shelf (COTS) equipment and software. The tested system consists of a video node, an Attitude Heading Reference System (AHRS), an Access Point and a User Interface Node. The video node consists of an IP Camera which was used to demonstrate the viability of including video recording as a service in an aircraft. The Attitude Heading Reference System was integrated with a GPS and a serial device server. The User Interface Node was installed with moving map software which receives the data from the AHRS and GPS to display flight information including topographic maps, attitude, heading, and velocity and roll/pitch/yaw rates. It was also used to record data from the video node. The Access Point was used to configure the network in the "Infrastructure mode". The system was also tested in the "Ad-Hoc mode" i.e., without an Access Point and suggestions for improving the performance of a system in the Ad-Hoc mode were made. The Infrastructure mode was flight tested in a Cessna 172. The data logged from the wireless AHRS during the flight test shows that it performed at its rated specification and that no data was lost due to disconnection in the wireless system. The post flight test data processing shows that the wireless system provided a secure, interference free connection with a throughput of 1.102 Mbps. By comparison, the popular ARINC 429 data bus supports a data rate of 100 Kbps. The developed system demonstrates the applicability of wireless networking using the IEEE 802.11 protocols for application in flight testing and based on this, future work like extending the system to include more number of clients is presented

Routing protocol evaluation and development of a fully functional simulation environment for vehicular ad hoc networks

A Vehicular Ad-hoc Networks (VANET) is an area of wireless technologies that are attracting a great deal of interest. There are still several areas of VANETS, such as medium access control, security and routing protocols, that lack large amounts of research. There is also a lack of freely available simulators that can quickly and accurately simulate VANETs. One of the two main goals of this thesis was to develop a freely available VANET simulator and to evaluate popular mobile ad-hoc network routing protocols in several VANET scenarios. The VANET simulator consisted of a network simulator, a traffic (mobility simulator) and used a client-server application to keep the two simulators in sync. The VANET simulator also models buildings in order to create a more realistic wireless network environment. The second main goal of this thesis was to provide an evaluation of the routing protocols that are commonly used in mobile ad-hoc networks, which will apply to VANETs. Ad-Hoc Distance Vector routing (AODV), Dynamic Source Routing (DSR) and Dynamic MANET On-demand (DYMO) were initially simulated in a city, country, and highway environment in order to provide an overall evaluation

Adaptive sampling in autonomous marine sensor networks

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2006In this thesis, an innovative architecture for real-time adaptive and cooperative control of autonomous sensor platforms in a marine sensor network is described in the context of the autonomous oceanographic network scenario. This architecture has three major components, an intelligent, logical sensor that provides high-level environmental state information to a behavior-based autonomous vehicle control system, a new approach to behavior-based control of autonomous vehicles using multiple objective functions that allows reactive control in complex environments with multiple constraints, and an approach to cooperative robotics that is a hybrid between the swarm cooperation and intentional cooperation approaches. The mobility of the sensor platforms is a key advantage of this strategy, allowing dynamic optimization of the sensor locations with respect to the classification or localization of a process of interest including processes which can be time varying, not spatially isotropic and for which action is required in real-time. Experimental results are presented for a 2-D target tracking application in which fully autonomous surface craft using simulated bearing sensors acquire and track a moving target in open water. In the first example, a single sensor vehicle adaptively tracks a target while simultaneously relaying the estimated track to a second vehicle acting as a classification platform. In the second example, two spatially distributed sensor vehicles adaptively track a moving target by fusing their sensor information to form a single target track estimate. In both cases the goal is to adapt the platform motion to minimize the uncertainty of the target track parameter estimates. The link between the sensor platform motion and the target track estimate uncertainty is fully derived and this information is used to develop the behaviors for the sensor platform control system. The experimental results clearly illustrate the significant processing gain that spatially distributed sensors can achieve over a single sensor when observing a dynamic phenomenon as well as the viability of behavior-based control for dealing with uncertainty in complex situations in marine sensor networks.Supported by the Office of Naval Research, with a 3-year National Defense Science and Engineering Grant Fellowship and research assistantships through the Generic Ocean Array Technology Sonar (GOATS) project, contract N00014-97-1-0202 and contract N00014-05-G-0106 Delivery Order 008, PLUSNET: Persistent Littoral Undersea Surveillance Network

Supporting Secure and Transparent Mobility in Wireless Local-Area Networks

Wireless Local Area Networks (WLANs) are experiencing unprecedented growth as the last mile connectivity solution. Mobility is an important feature of any wireless communication system. Handoffs are a crucial link level functionality that enable a mobile user to stay connected to a wireless network by switching the data connection from one base station or access point to another. Conceptually the handoff process can be subdivided into two phases: (i) Discovery - wherein the client searches for APs in vicinity and (ii) Authentication - the client authenticates to an AP selected from the discovery phase. The handoff procedure recommended by the IEEE 802.11 standard and closely implemented by various wireless vendors is an intrusive and a brute-force approach. My testbed based study of these algorithms showed that they incur high latencies varying between 400ms to 1.3 seconds depending on the security settings in effect. Such inefficient handoff mechanisms can have a detrimental impact on applications especially synchronous multimedia connections such as Voice over IP. In my dissertation, I have proposed and evaluated the notion of locality among APs induced by user mobility patterns. A relation is created among APs which captures this locality in a graph theoretic manner called neighbor graphs -- a distributed structure that autonomously captures such locality. Based on this, I have designed and evaluated efficient mechanisms to address the two different phases of this handoff process. Through a rigorous testbed based implementation, I have demonstrated the viability of the concept of mobility induced locality through good performance improvements. Through extensive simulations I have studied the performance of proposed handoff mechanisms over various different topologies. This work has shown that a topological structure which captures the locality relationship among APs is fundamental to designing mechanisms that make user mobility transparent from the higher layers of the networking stack