Delay Tolerant Networks for Efficient Information Harvesting and Distribution in Intelligent Transportation Systems

[EN] Intelligent Transportation Systems (ITS) can make transportation safer, more efficient, and more sustainable by applying various information and communication technologies. One of these technologies are \acfp{VN}. \acp{VN} combine different communication solutions such as cellular networks, \acfp{VANET}, or IEEE 802.11 technologies to provide connectivity among vehicles, and between vehicles and road infrastructure. This thesis focuses on VNs, and considers that the high speed of the nodes and the presence of obstacles like buildings, produces a highly variable network topology, as well as more frequent partitions in the network. Therefore, classical \ac{MANET} protocols do not adapt well to VANETs. Under these conditions, \ac{DTN} have been proposed as an alternative able to cope with these adverse characteristics. In DTN, when a message cannot be routed to its destination, it is not immediately dropped but it is instead stored and carried until a new route becomes available. The combination of VN and DTN is called \acp{VDTN}. In this thesis, we propose a new VDTN protocol designed to collect information from vehicular sensors. Our proposal, called \ac{MSDP}, combines information about the localization obtained from a GNSS system with the actual street/road layout obtained from a Navigation System (NS) to define a new routing metric. Both analytical and simulation results prove that MSDP outperforms previous proposals. Concerning the deployment of VNs and VANET technologies, technology already left behind the innovation and the standardization phases, and it is about time it reach the first early adopters in the market. However, most car manufacturers have decided to implement VN devices in the form of On Board Units (OBUs), which are expensive, heavily manufacturer dependent, and difficult to upgrade. These facts are delaying the deployment of VN. To boost this process, we have developed the GRCBox architecture. This architecture is based on low-cost devices and enables the establishment of V2X, \emph{i.e.} V2I and V2V, communications while integrating users by easing the use of general purpose devices like smartphones, tablets or laptops. To demonstrate the viability of the GRCBox architecture, we combined it with a DTN platform called Scampi to obtain actual results over a real VDTN scenario. We also present several GRCBox-aware applications that illustrate how developers can create applications that bring the potential of VN to user devices.[ES] Los sistemas de transporte inteligente (ITS) son el soporte para el establecimiento de un transporte más seguro, más eficiente y más sostenible mediante el uso de tecnologías de la información y las comunicaciones. Una de estas tecnologías son las redes vehiculares (VNs). Las VNs combinan diferentes tecnologías de comunicación como las redes celulares, las redes ad-hoc vehiculares (VANETs) o las redes 802.11p para proporcionar conectividad entre vehículos, y entre vehículos y la infraestructura de carreteras. Esta tesis se centra en las VNs, en las cuales la alta velocidad de los nodos y la presencia de obstáculos como edificios producen una topología de red altamente variable, así como frecuentes particiones en la red. Debido a estas características, los protocolos para redes móviles ad-hoc (MANETs) no se adaptan bien a las VANETs. En estas condiciones, las redes tolerantes a retardos (DTNs) se han propuesto como una alternativa capaz de hacer frente a estos problemas. En DTN, cuando un mensaje no puede ser encaminado hacia su destino, no es inmediatamente descartado sino es almacenado hasta que una nueva ruta esta disponible. Cuando las VNs y las DTNs se combinan surgen las redes vehiculares tolerantes a retardos (VDTN). En esta tesis proponemos un nuevo protocolo para VDTNs diseñado para recolectar la información generada por sensores vehiculares. Nuestra propuesta, llamada MSDP, combina la información obtenida del servicio de información geográfica (GIS) con el mapa real de las calles obtenido del sistema de navegación (NS) para definir una nueva métrica de encaminamiento. Resultados analíticos y mediante simulaciones prueban que MSDP mejora el rendimiento de propuestas anteriores. En relación con el despliegue de las VNs y las tecnologías VANET, la tecnología ha dejado atrás las fases de innovación y estandarización, ahora es el momento de alcanzar a los primeros usuarios del mercado. Sin embargo, la mayoría de fabricantes han decidido implementar los dispositivos para VN como unidades de a bordo (OBU), las cuales son caras y difíciles de actualizar. Además, las OBUs son muy dependientes del fabricante original. Todo esto esta retrasando el despliegue de las VNs. Para acelerar la adopción de las VNs, hemos desarrollado la arquitectura GRCBox. La arquitectura GRCBox esta basada en un dispositivo de bajo coste que permite a los usuarios usar comunicaciones V2X (V2V y V2I) mientras utilizan dispositivos de propósito general como teléfonos inteligentes, tabletas o portátiles. Las pruebas incluidas en esta tesis demuestran la viabilidad de la arquitectura GRCBox. Mediante la combinación de nuestra GRCBox y una plataforma de DTN llamada Scampi hemos diseñado y probado un escenario VDTN real. También presentamos como los desarrolladores pueden crear nuevas aplicaciones GRCBox para llevar el potencial de las VN a los dispositivos de usuario.[CA] Els sistemes de transport intel·ligent (ITS) poden crear un transport més segur, més eficient i més sostenible mitjançant l'ús de tecnologies de la informació i les comunicacions aplicades al transport. Una d'aquestes tecnologies són les xarxes vehiculars (VN). Les VN combinen diferents tecnologies de comunicació, com ara les xarxes cel·lulars, les xarxes ad-hoc vehiculars (VANET) o les xarxes 802.11p, per a proporcionar comunicació entre vehicles, i entre vehicles i la infraestructura de carreteres. Aquesta tesi se centra en les VANET, en les quals l'alta velocitat dels nodes i la presència d'obstacles, com els edificis, produeixen una topologia de xarxa altament variable, i també freqüents particions en la xarxa. Per aquest motiu, els protocols per a xarxes mòbils ad-hoc (MANET) no s'adapten bé. En aquestes condicions, les xarxes tolerants a retards (DTN) s'han proposat com una alternativa capaç de fer front a aquests problemes. En DTN, quan un missatge no pot ser encaminat cap a la seua destinació, no és immediatament descartat sinó que és emmagatzemat fins que apareix una ruta nova. Quan les VN i les DTN es combinen sorgeixen les xarxes vehicular tolerants a retards (VDTN). En aquesta tesi proposem un nou protocol per a VDTN dissenyat per a recol·lectar la informació generada per sensors vehiculars. La nostra proposta, anomenada MSDP, combina la informació obtinguda del servei d'informació geogràfica (GIS) amb el mapa real dels carrers obtingut del sistema de navegació (NS) per a definir una nova mètrica d'encaminament. Resultats analítics i mitjançant simulacions proven que MSDP millora el rendiment de propostes prèvies. En relació amb el desplegament de les VN i les tecnologies VANET, la tecnologia ha deixat arrere les fases d'innovació i estandardització, ara és temps d'aconseguir als primers usuaris del mercat. No obstant això, la majoria de fabricants han decidit implementar els dispositius per a VN com a unitats de bord (OBU), les quals són cares i difícils d'actualitzar. A més, les OBU són molt dependents del fabricant original. Tot això està retardant el desplegament de les VN. Per a accelerar l'adopció de les VN, hem desenvolupat l'arquitectura GRCBox. L'arquitectura GRCBox està basada en un dispositiu de baix cost que permet als usuaris usar comunicacions V2V mentre usen dispositius de propòsit general, com ara telèfons intel·ligents, tauletes o portàtils. Les proves incloses en aquesta tesi demostren la viabilitat de l'arquitectura GRCBox. Mitjançant la combinació de la nostra GRCBox i la plataforma de DTN Scampi, hem dissenyat i provat un escenari VDTN pràctic. També presentem com els desenvolupadors poden crear noves aplicacions GRCBox per a portar el potencial de les VN als dispositius d'usuari.Martínez Tornell, S. (2016). Delay Tolerant Networks for Efficient Information Harvesting and Distribution in Intelligent Transportation Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68486TESI

The Dynamics of Vehicular Networks in Urban Environments

Vehicular Ad hoc NETworks (VANETs) have emerged as a platform to support intelligent inter-vehicle communication and improve traffic safety and performance. The road-constrained, high mobility of vehicles, their unbounded power source, and the emergence of roadside wireless infrastructures make VANETs a challenging research topic. A key to the development of protocols for inter-vehicle communication and services lies in the knowledge of the topological characteristics of the VANET communication graph. This paper explores the dynamics of VANETs in urban environments and investigates the impact of these findings in the design of VANET routing protocols. Using both real and realistic mobility traces, we study the networking shape of VANETs under different transmission and market penetration ranges. Given that a number of RSUs have to be deployed for disseminating information to vehicles in an urban area, we also study their impact on vehicular connectivity. Through extensive simulations we investigate the performance of VANET routing protocols by exploiting the knowledge of VANET graphs analysis.Comment: Revised our testbed with even more realistic mobility traces. Used the location of real Wi-Fi hotspots to simulate RSUs in our study. Used a larger, real mobility trace set, from taxis in Shanghai. Examine the implications of our findings in the design of VANET routing protocols by implementing in ns-3 two routing protocols (GPCR & VADD). Updated the bibliography section with new research work

Applying DTN Routing for Reservation-Driven EV Charging Management in Smart Cities

Charging management for Electric Vehicles (EVs) on-the-move (moving on the road with certain trip destinations) is becoming important, concerning the increasing popularity of EVs in urban city. However, the limited battery volume of EV certainly influences its driver’s experience. This is mainly because the EV needed for intermediate charging during trip, may experience a long service waiting time at Charging Station (CS). In this paper, we focus on CS-selection decision making to manage EVs’ charging plans, aiming to minimize drivers’ trip duration through intermediate charging at CSs. The anticipated EVs’ charging reservations including their arrival time and expected charging time at CSs, are brought for charging management, in addition to taking the local status of CSs into account. Compared to applying traditionally applying cellular network communication to report EVs’ charging reservations,we alternatively study the feasibility of applying Vehicle-to-Vehicle (V2V) communication with Delay/Disruption Tolerant Networking (DTN) nature, due primarily to its flexibility and cost-efficiency in Vehicular Ad hoc NETworks (VANETs). Evaluation results under the realistic Helsinki city scenario show that applying the V2V for reservation reporting is promisingly cost-efficient in terms of communication overhead for reservation making, while achieving a comparable performance in terms of charging waiting time and total trip duration

Transmissão oportunística de informação em redes veiculares

Mestrado em Engenharia Eletrónica e TelecomunicaçõesThe development in telecommunications and particularly in wireless communications has been one of the most striking features of the contemporary world. The globalization only has been possible thanks to the evolution of communication technologies which increasingly have allowed to satisfy the constant people's needs of being "always connected" whatever the environment where they are. Concerning the evolution of technologies, vehicular networks have been one of the areas of great interest. This interest has been manifested both in research and in the development of the automotive industry that has produced innovative vehicles which are more and more equipped with new technologies. It is expected that communication in vehicular networks enable not only the communication between vehicles, but also a more comfortable and safe driving, making the user's experience of this type of networks richer and stimulating. The specific characteristics of vehicular networks, namely the high mobility, unpredictable routes, dynamic topology and the consequent and constant loss of connectivity, have been a challenge that has motivated studies to find solutions to these limitations. The work carried out for this dissertation is in the area of Vehicular Ad-hoc Networks (VANETs) and it is based on the Delay and Disruption Tolerant Networks (DTNs). With this project, identified as "Opportunistic Transmission of Information in Vehicular Networks", we aim to study the communication and transmission of information in these networks which do not allow communication without delays and disruptions. For this purpose it is studied the performance of DTN mechanisms in these networks. In this work it is used the implementation IBR-DTN to test DTN in VANETs. This implementation showed, in previous works, to be the one that presents the best performance comparing it with other existing implementations. The study involved, in an initial phase, reading and analyzing the implementation code so that it was possible to add instructions that allowed to observe the behavior of the implementation in the several tests carried out, as well as the correction of the bugs in the implementation. In the first phase, in laboratory, with fixed nodes and in a controlled environment, several scenarios were created to simulate the possible situations a node can meet: direct transfer with and without delay, indirect transfer (multi-hop) and indirect transfer with delay which corresponds to the store and transport of the bundles (set of information) until the next node. From the analysis of the collected information and observing the corresponding graphs, it was possible to observe that the implementation was working properly in the vehicles equipment for communication. Still in laboratory it was built an heterogeneous network with several devices (servers, NetRiders, Single Board Computers (SBCs), tablet, Raspberry Pi e Macbook) to show the integration of the IBR-DTN implementation and its extension in different equipments. During this test several files were sent among these devices, which were correctly received in the nodes previously defined as destination nodes. After testing and checking that everything was working properly in the laboratory, the same implementation was transferred to a testbed with 25 vehicles and 3 fixed infrastructures in Leixões harbor. In this testbed several DTN routing protocols were tested in order to check which of them showed better performance in the delivery rate of the bundles and of the collected information (the log files were also delivered via DTN) from the On-Board Units (OBUs) to the server, located in the Internet. The routing protocol with static routes to the Road Side Units (RSUs) proved a better efficiency compared to the other protocols. This was due to the the fact that this network is well covered with RSUs, and there is no relation between the historic of contacts and the probability that the vehicles will meet again in the future.O desenvolvimento na área das telecomunicações e, mais particularmente, nas comunicações sem-fios tem sido um dos traços mais marcantes do mundo actual. A globalização só tem sido possível graças à evolução dos meios de comunicação que cada vez mais permitem satisfazer a constante necessidade das pessoas estarem sempre ligadas, qualquer que seja o ambiente em que se encontrem. As redes veiculares têm sido uma das áreas de elevado interesse na evolução das tecnologias. Esse interesse tem-se manifestado tanto ao nível da investigação como ao nível do desenvolvimento da indústria automóvel que tem produzido veículos cada vez mais equipados com novas tecnologias. Prevê-se que a comunicação em redes veiculares permitam não só a comunicação entre os veículos, mas também uma condução mais confortável e segura, tornando a experiência dos utilizadores deste tipo de redes mais rica e estimulante. As características específicas das redes veiculares, nomeadamente a elevada mobilidade, rotas imprevisíveis, topologia dinâmica e a consequente e constante perda de conectividade, tornam-se um desafio que tem motivado estudos no sentido de se encontrarem soluções para essas limitações. O trabalho desenvolvido para esta dissertação insere-se na área das Vehicular Ad-hoc NETworks (VANETs) e baseia-se nas Delay and Disruption Tolerant Networks (DTNs). Com este projecto, identificado como "Transmissão Oportunística de Informação em Redes Veiculares", pretende-se estudar a comunicação e envio de informação nas redes que permitem uma comunicação com atrasos e disrupções. Para o efeito é estudado o desempenho de mecanismos de DTN nestas redes. Neste trabalho é utilizada a implementação IBR-DTN para testar DTN nas redes veiculares. Esta implementação mostrou, em trabalhos anteriores, ser aquela que apresenta melhor desempenho face a outras que existem. O estudo envolveu, numa fase inicial, a leitura e analise de código da implementação para que fosse possível adicionar instruções que permitissem observar o comportamento da implementação nos diversos testes realizados, bem como a correcção de erros da implementação. Na primeira fase, em laboratório, com nos fixos e num ambiente controlado, foram realizados vários cenários que mostram as situações possíveis que um nó pode encontrar: transferência direta com e sem atraso, transferência indirecta (multi-hop) e transferência indirecta com atraso que corresponde ao armazenamento e transporte dos bundles (conjunto de informação) até ao próximo nó. A partir da analise da informação recolhida e observação dos gráficos obtidos foi possível verificar o correcto funcionamento da implementação nos equipamentos de comunicação entre veículos. Ainda em laboratório foi construída uma rede heterogénea com diversos dispositivos (servidores, NetRiders, Single Board Computers (SBCs), tablet, Raspberry Pi e Macbook) com o objectivo de mostrar a integração da implementação IBR-DTN e as suas extensões em diferentes equipamentos. Neste teste foram enviados ficheiros entre estes dispositivos, os quais foram recebidos correctamente nos nos definidos como destino. Depois de testar e certificar que tudo funcionava em laboratório, a mesma implementação foi transferida para uma testbed com 25 veículos e 3 infraestruturas fixas, no porto de Leixões. Nesta testbed foram testados diversos protocolos de encaminhamento DTN de forma a verificar qual apresentava melhor desempenho na taxa de entrega dos bundles e da informação recolhida (os ficheiros de log foram também entregues através de DTN) das On-Board Units (OBUs) para o servidor, localizado na Internet. O protocolo com rotas estáticas para as Road Side Units (RSUs) demonstrou uma melhor eficiência em relação aos restantes devido ao facto de esta rede estar bem coberta e de não existir uma relação entre o histórico de contactos e a probabilidade de os veículos se encontrarem novamente

Routing and Applications of Vehicular Named Data Networking

Vehicular Ad hoc NETwork (VANET) allows vehicles to exchange important informationamong themselves and has become a critical component for enabling smart transportation.In VANET, vehicles are more interested in content itself than from which vehicle the contentis originated. Named Data Networking (NDN) is an Internet architecture that concentrateson what the content is rather than where the content is located. We adopt NDN as theunderlying communication paradigm for VANET because it can better address a plethora ofproblems in VANET, such as frequent disconnections and fast mobility of vehicles. However,vehicular named data networking faces the problem of how to efficiently route interestpackets and data packets. To address the problem, we propose a new geographic routing strategy of applying NDNin vehicular networks with Delay Tolerant Networking (DTN) support, called GeoDTN-NDN. We designed a hybrid routing mechanism for solving the flooding issue of forwardinginterest packets and the disruption problem of delivering data packets. To avoid disruptionscaused by routing packets over less-traveled roads, we develop a new progressive segmentrouting approach that takes into consideration how vehicles are distributed among differentroads, with the goal of favoring well-traveled roads. A novel criterion for determiningprogress of routing is designed to guarantee that the destination will be reached no matterwhether a temporary loop may be formed in the path. We also investigate applications of vehicular named data networking. We categorizethese applications into four types and design an NDN naming scheme for them. We proposea fog-computing based architecture to support the smart parking application, which enablesa driver to find a parking lot with available parking space and make reservation for futureparking need. Finally we describe several future research directions for vehicular nameddata networking

Cooperative Content Dissemination on Vehicle Networks

As redes veiculares têm sido alvo de grandes avanços nos últimos anos, sobretudo devido ao crescente interesse por veículos inteligentes e autónomos que motiva investimentos avultados por parte da indústria automóvel. A inexistência de uma forma oportuna e económica de executar atualizações OTA (over-the-air) está a contribuir para o adiar do lançamento de grandes frotas de veículos inteligentes. O custo associado à transmissão de dados através de redes celulares é muito elevado e não se pode garantir que cada veículo tenha acesso a uma estação ou estacionamento com conectividade adequada em tempo útil, onde possa obter os dados esperados. Com base nestas premissas, esta tese apresenta a concepção e implementação de um protocolo cooperativo de disseminação de conteúdos que aproveita as ligações Veículo-a-Veículo (V2V) para assegurar uma distribuição de dados pela rede com custos reduzidos. Além disso, este trabalho é complementado e suportado com uma análise do desempenho do protocolo numa rede de 25 veículos.Vehicular networks have seen great advancements over the last few years, mostly due to the increased eagerness for smart and autonomous vehicles that motivate hefty investments by the automotive industry. The absence of a timely and cost-effective way to perform over-the-air (OTA) updates is contributing to defer the deployment of large fleets of connected vehicles. There is a high cost associated with transmitting data over cellular networks and it cannot be expected that every vehicle has access to a station or depot with adequate connectivity where it can get the awaited data cheaply nor that this solution happens timely enough. With this in mind, this thesis presents the design and implementation of a cooperative content dissemination protocol that takes advantage of Vehicle-to-Vehicle (V2V) communication links to distribute data across a network with reduced costs. Moreover, this work is complemented with a performance analysis of the protocol on a deployed network of 25 vehicles