Abstract

Mestrado em Engenharia de Computadores e Telemática Vehicular networks, also known as VANETs, are an ad-hoc network formed by vehicles and road-side units. Nowadays they have been attracting big interest both from researchers as from the automotive industry. With the upcoming of automotive specific operating systems and self-driving cars, the use of applications on vehicles and the integration with common mobile devices is becoming a big part of VANETs. Although many advances have been made on this field, there is still a big discrepancy between the communication layer services provided by VANETs and the user level services, namely those accessible through mobile applications on other networks and technologies. Users and developers are accustomed to user-to-user or user-tobusiness communication without explicit concerns related with the available communication transport layer. Such is not possible in VANETs since people may use more than one vehicle. However, to send a message to a specific user in these networks, there is a need to know the ID of the vehicle where the user is, meaning that there is a lack of services that map each individual user to VANETs endpoint (vehicle identification). This dissertation work proposes VANESS, a naming service as a resource to support user-to-user communication within a heterogeneous scenario comprising typical ISP scenario and VANETs focused on mobile devices. The proposed system is able to map the user to an end point either locally (i.e. there is not internet connection at all), online (i.e. system is not in a vehicular network but has direct internet connection) and using a gateway (i.e. the system is in a vehicular network where some of the nodes have internet access and will act as a gateway). VANESS was fully implemented on android OS with results proving his viability, and partially on iOS showing its multiplatform capabilities. As redes veiculares, também conhecidas por VANETs, são redes ad-hoc formadas por veículos e road-site units. Hoje em dia estas redes têm atraído bastante interesse tanto por parte de investigadores como da indústria automóvel. Com o aparecimento de sistemas operativos especificamente dedicados a automóveis e carros de condução autónoma, o uso de aplicações em veículos e a integração com dipositivos móveis está-se a tornar uma parte cada vez maior nas VANETs. Apesar dos grandes avanços tecnológicos realizados nesta área, ainda existe uma grande discrepância entre os serviços de camada de comunicação disponibilizados pelas VANETs e os serviços ao nível do utilizador, nomeadamente aqueles acessíveis a partir de aplicações móveis noutras redes e tecnologias. Os utilizadores e programadores estão habituados a interações utilizador-utilizador ou utilizadorempresa sem preocupações explícitas sobre a camada de transporte em causa. Isto não é possível em redes VANETs, uma vez que cada pessoa pode usar vários veículos. No entanto, uma mensagem para ser enviada para um utilizador específico através destas redes precisa do indentificador do veículo onde tal utilizador está, ou seja, existe uma falta de serviços que mapeiem cada utilizador individual a nós na VANET (identificação do veículo). O trabalho desta dissertação propõe o sistema VANESS, um serviço de nomes (naming service) disponibilizado como um recurso para suporte a comunicação utilizador-a-utilizador num cenário heterogéneo englobando o típico ISP e VANETs focadas em dispositivos móveis. O sistema proposto é capaz de mapear um utilizador a um veículo tanto localmente (i.e. não existe ligação à internet), online (i.e. o sistema não está numa rede veicular mas tem acesso direto à internet) e usando um gateway (i.e. o sistema está numa rede veicular onde algum nó tem acesso à internet e irá servir como gateway). VANESS foi integralmente implementado em Android OS, onde os resultados dos testes mostram que é um sistema viável, e parcialmente em iOS mostrando a sua capacidade para multi-plataformas.

Abstract

International audience; Vehicular networks are one of the cornerstone of an Intelligent Transportation System (ITS). They are expected to provide ubiquitous network connectivity to moving vehicles while supporting various ITS services, some with very stringent requirements in terms of latency and reliability. Two vehicular networking technologies are envisioned to jointly support the full range of ITS services : DSRC (Dedicated Short Range Communication) for direct vehicle to vehicle/Road Side Units (RSU) communications and cellular technologies. To the best of our knowledge, approaches from the literature usually divide ITS services on each of these networks according to their requirements and one single network is in charge of supporting the each service. Those that consider both network technologies to offer multi-path routing, load balancing or path splitting for a better quality of experience of ITS services assume obviously separately controlled networks. Under the umbrella of SDN (Software Defined Networking), we propose in this paper a hybrid network architecture that enables the joint control of the networks providing connectivity to multi-homed vehicles and, also, explore the opportunities brought by such an architecture. We show through some use cases, that in addition to the flexibility and fine-grained programmability brought by SDN, it opens the way towards the development of effective network control algorithms that are the key towards the successful support of ITS services and especially those with stringent QoS. We also show how these algorithms could also benefit from information related to the environment or context in which vehicles evolve (traffic density, planned trajectory, ..), which could be easily collected by data providers and made available via the cloud.