Coherent, automatic address resolution for vehicular ad hoc networks

Published in: Int. J. of Ad Hoc and Ubiquitous Computing, 2017 Vol.25, No.3, pp.163 - 179. DOI: 10.1504/IJAHUC.2017.10001935The interest in vehicular communications has increased notably. In this paper, the use of the address resolution (AR) procedures is studied for vehicular ad hoc networks (VANETs). We analyse the poor performance of AR transactions in such networks and we present a new proposal called coherent, automatic address resolution (CAAR). Our approach inhibits the use of AR transactions and instead increases the usefulness of routing signalling to automatically match the IP and MAC addresses. Through extensive simulations in realistic VANET scenarios using the Estinet simulator, we compare our proposal CAAR to classical AR and to another of our proposals that enhances AR for mobile wireless networks, called AR+. In addition, we present a performance evaluation of the behaviour of CAAR, AR and AR+ with unicast traffic of a reporting service for VANETs. Results show that CAAR outperforms the other two solutions in terms of packet losses and furthermore, it does not introduce additional overhead.Postprint (published version

Formulation, implementation considerations, and first performance evaluation of algorithmic solutions - D4.1

Deliverable D4.1 del projecte Europeu OneFIT (ICT-2009-257385)This deliverable contains a first version of the algorithmic solutions for enabling opportunistic networks. The presented algorithms cover the full range of identified management tasks: suitability, creation, QoS control, reconfiguration and forced terminations. Preliminary evaluations complement the proposed algorithms. Implementation considerations towards the practicality of the considered algorithms are also included.Preprin

Encaminhamento baseado no contexto em ICNs móveis

Over the last couple of decades, vehicular ad hoc networks (VANETs) have been at the forefront of research, yet still are afflicted by high network fragmentation, due to their continuous node mobility and geographical dispersion. To address these concerns, a new paradigm was proposed - Information-Centric Networks(ICN), whose focus is the delivery of Content based on names, being ideal to attend to high latency environments. However, the main proposed solutions for content delivery in ICNs do not take into account the type of content nor the various available communication interfaces in each point of the network, a factor which can be deciding in mobile networks. The scope of this dissertation lies on the use of ICNs concepts for the delivery of both urgent and non-urgent information in urban mobile environments. In order to do so, a context-based forwarding strategy was proposed, with a very clear goal: to take advantage of both packet names and Data, and node's neighborhood analysis in order to successfully deliver content into the network in the shortest period of time, and without worsening network congestion. The design, implementation and validation of the proposed strategy was performed using the ndnSIM platform simulator along with real mobility traces from communication infrastructure of the Porto city. The results show that the proposed context-based forwarding strategy for mobile ICN presents a clear improvement in performance in terms of delivery, while maintaining network overhead at a constant. Furthermore, by means of better pathing and through cooperation with caching mechanisms, lower transmission delays can be attained.Nas últimas décadas, as redes veiculares ad hoc (VANETs) estiveram na vanguarda da pesquisa, mas continuam a ser afetadas por alta fragmentação na rede, devido à mobilidade contínua dos nós e a sua dispersão geográfica. Para abordar estes problemas, um novo paradigma foi proposto - Redes Centradas na Informação (ICN), cujo foco é a entrega de Conteúdo com base em nomes, sendo ideal para atender ambientes de alta latência. No entanto, as principais soluções propostas para entrega de conteúdo em ICNs não têm em conta o tipo de conteúdo nem as várias interfaces de comunicação disponíveis em cada ponto da rede, fator que pode ser determinante em redes móveis. O objetivo desta dissertação reside no uso dos conceitos de ICNs para a entrega de informações urgentes e não urgentes em ambientes móveis urbanos. Para isso, foi proposta uma estratégia de encaminhamento baseada em contexto, com um objetivo muito claro: tirar proveito do nome e dados dos pacotes, e da análise de vizinhança dos nós, com vista em fornecer com êxito o conteúdo para a rede no menor período de tempo e sem piorar o congestionamento da rede. O desenho, implementação e validação da estratégia proposta foram realizados usando o simulador ndnSIM, juntamente com traces reais de mobilidade da infraestrutura de comunicação da cidade do Porto. Os resultados mostram que a estratégia de encaminhamento baseada em contexto proposta para o ICN móvel apresenta uma clara melhoria no desempenho em termos de entrega, mantendo a carga da rede constante. Além disso, através da escolha de melhores caminhos e através da cooperação com mecanismos de armazenamento em cache, é possível alcançar atrasos de transmissão mais baixos.Mestrado em Engenharia de Computadores e Telemátic

Wireless body sensor networks for health-monitoring applications

This is an author-created, un-copyedited version of an article accepted for publication in Physiological Measurement. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0967-3334/29/11/R01

Cross-layer energy optimisation of routing protocols in wireless sensor networks

Recent technological developments in embedded systems have led to the emergence of a new class of networks, known asWireless Sensor Networks (WSNs), where individual nodes cooperate wirelessly with each other with the goal of sensing and interacting with the environment.Many routing protocols have been developed tomeet the unique and challenging characteristics of WSNs (notably very limited power resources to sustain an expected lifetime of perhaps years, and the restricted computation, storage and communication capabilities of nodes that are nonetheless required to support large networks and diverse applications). No standards for routing have been developed yet for WSNs, nor has any protocol gained a dominant position among the research community. Routing has a significant influence on the overall WSN lifetime, and providing an energy efficient routing protocol remains an open problem. This thesis addresses the issue of designing WSN routing methods that feature energy efficiency. A common time reference across nodes is required in mostWSN applications. It is needed, for example, to time-stamp sensor samples and for duty cycling of nodes. Alsomany routing protocols require that nodes communicate according to some predefined schedule. However, independent distribution of the time information, without considering the routing algorithm schedule or network topology may lead to a failure of the synchronisation protocol. This was confirmed empirically, and was shown to result in loss of connectivity. This can be avoided by integrating the synchronisation service into the network layer with a so-called cross-layer approach. This approach introduces interactions between the layers of a conventional layered network stack, so that the routing layer may share information with other layers. I explore whether energy efficiency can be enhanced through the use of cross-layer optimisations and present three novel cross-layer routing algorithms. The first protocol, designed for hierarchical, cluster based networks and called CLEAR (Cross Layer Efficient Architecture for Routing), uses the routing algorithm to distribute time information which can be used for efficient duty cycling of nodes. The second method - called RISS (Routing Integrated Synchronization Service) - integrates time synchronization into the network layer and is designed to work well in flat, non-hierarchical network topologies. The third method - called SCALE (Smart Clustering Adapted LEACH) - addresses the influence of the intra-cluster topology on the energy dissipation of nodes. I also investigate the impact of the hop distance on network lifetime and propose a method of determining the optimal location of the relay node (the node through which data is routed in a two-hop network). I also address the problem of predicting the transition region (the zone separating the region where all packets can be received and that where no data can be received) and I describe a way of preventing the forwarding of packets through relays belonging in this transition region. I implemented and tested the performance of these solutions in simulations and also deployed these routing techniques on sensor nodes using TinyOS. I compared the average power consumption of the nodes and the precision of time synchronization with the corresponding parameters of a number of existing algorithms. All proposed schemes extend the network lifetime and due to their lightweight architecture they are very efficient on WSN nodes with constrained resources. Hence it is recommended that a cross-layer approach should be a feature of any routing algorithm for WSNs

Formulations and identification of algorithmic solutions for enabling opportunistic networks - M4.1

Milestone M4.1 del projecte Europeu OneFIT (ICT-2009-257385).This document contains a detailed description of the algorithms to be implemented to manage the opportunistic networks. There are defined according to the functional and system architecture (WP2) to fulfil the technical challenges. These algorithms will implemented during the WP4.2 and validated during the WP4.3Postprint (published version

AN ADAPTIVE INFORMATION DISSEMINATION MODEL FOR VANET COMMUNICATION

Vehicular ad hoc networks (VANETs) have been envisioned to be useful in road safety and many commercial applications. The growing trend to provide communication among the vehicles on the road has provided the opportunities for developing a variety of applications for VANET. The unique characteristics of VANET bring about new research challenges