Esta tesis propone (i) algunas soluciones para reducir, mediante el uso de redes inalámbricas Wi-Fi y aprovechando la cooperación entre los nodos, el consumo de datos en redes celulares, (ii) estudia cómo hacer un buen despliegue de puntos deacceso para optimizar la difusión de contenidos, (iii) analiza el impacto de mecanismos usados para disminuir el consumo de energía en los nodos, (iv) así como explora algunos de las riesgos que surgen en estas redes.Entre las aplicaciones a tener en cuenta para la reducción de la carga que soportan las redes celulares, podemos encontrar la Diseminación de Información en Redes Móviles Ad-Hoc.En esta tesis, las redes móviles en que nos vamos a centrar, consistirán principalmente en Redes Vehiculares Ad-hoc y Redes Peatonales Ad-hoc.En ambos escenarios trataremos con aplicaciones que tienen el fin de diseminar contenidos vehículo a vehículo o peatón a peatón, así como de vehículo a infraestructura o de peatón a infraestructura.Veremos cómo ambos escenarios (vehículos y peatones) comparten varias características, mientras que por otro lado, existen diferencias importantes que los hacen únicos y que por lo tanto, requieren de soluciones específicas. Por ejemplo, las baterías de los vehículos relegan técnicas de ahorro de energía en el funcionamiento de la red a un segundo lugar, mientras que en las redes peatonales las técnicas de ahorro de energía y sus efectos en el rendimiento de la red son un tema muy relevante.Mientras que las redes celulares ofrecen cobertura geográfica total, en soluciones de redes Wi-Fi oportunistas el paradigma del corto alcance sin cobertura permanente, así como la alta movilidad de los nodos de la red, requiere de diferentes abstracciones o paradigmas de red, como son las redes oportunistas, Redes tolerantes al retardo o disrupciones y el Network Coding para poder analizarlos.Y como ejemplo concreto de aplicación de Difusión en redes móviles, estudiaremos también, la propagación de malware en las redes móviles. A pesar de que se basa en los mismos mecanismos de propagación ya estudiados en otros escenarios, veremoscómo esta aplicación supone una nueva perspectiva en cuanto a la Diseminación de información.
This thesis proposes some solutions to relieve, using Wi-Fi wireless networks, the data consumption of cellular networks using cooperation between nodes, studies how to make a good deployment of access points to optimize the dissemination of contents, analyzes some mechanisms to reduce the nodes' power consumption during data dissemination in opportunistic networks, as well as explores some of the risks that arise in these networks.
Among the applications that are being discussed for data off-loading from cellular networks, we can find Information Dissemination in Mobile Networks.
In particular, for this thesis, the Mobile Networks will consist of Vehicular Ad-hoc Networks and Pedestrian Ad-Hoc Networks. In both scenarios we will find applications with the purpose of vehicle-to-vehicle or pedestrian-to-pedestrian Information
dissemination, as well as vehicle-to-infrastructure or pedestrian-to-infrastructure Information dissemination. We will see how both
scenarios (vehicular and pedestrian) share many characteristics, while on the other hand some differences make them unique, and therefore requiring of specific solutions. For example, large car batteries relegate power saving techniques to a second place, while power-saving techniques and its effects to network performance is a really relevant issue in Pedestrian networks.
While Cellular Networks offer geographically full-coverage, in opportunistic Wi-Fi wireless solutions the short-range non-fullcoverage paradigm as well as the high mobility of the nodes requires different network abstractions like opportunistic networking,
Disruptive/Delay Tolerant Networks (DTN) and Network Coding to analyze them.
And as a particular application of Dissemination in Mobile Networks, we will study the malware spread in Mobile Networks.
Even though it relies on similar spreading mechanisms, we will see how it entails a different perspective on Dissemination.
Gramaglia, Marco; Trullols Cruces, Oscar; Naboulsi, Diala; Fiore, Marco; Calderón, Maria IEEE International Conference on Sensing Communication and Networking p. 423-431 DOI: 10.1109/SAHCN.2014.6990380 Presentation's date: 2014-07-03 Presentation of work at congresses
There is a growing need for vehicular mobility datasets that can be employed in the simulative evaluation of protocols and architectures designed for upcoming vehicular networks.
Such datasets should be realistic, publicly available, and heterogeneous, i.e., they should capture varied traffic conditions. In this paper, we contribute to the ongoing effort to define such mobility
scenarios by introducing a novel set of traces for vehicular network simulation. Our traces are derived from high-resolution real-world traffic counts, and describe the road traffic on two highways
around Madrid, Spain, at several hours of different working days. We provide a thorough discussion of the real-world data underlying our study, and of the synthetic trace generation process.
Finally, we assess the potential impact of our dataset on networking studies, by characterizing the connectivity of vehicular networks built on the different traces. Our results underscore the dramatic impact that relatively small communication range variations have on the network. Also, they unveil previously unknown temporal dynamics of the topology of highway vehicular networks, and identify their causes.
Uppoor, Sandesh; Trullols Cruces, Oscar; Fiore, Marco; Barcelò Ordinas, José María IEEE transactions on mobile computing Vol. 13, num. 5, p. 1061-1075 DOI: 10.1109/TMC.2013.27 Date of publication: 2014-05 Journal article
The surge in vehicular network research has led, over the last few years, to the proposal of countless network solutions specifically designed for vehicular environments. A vast majority of such solutions has been evaluated by means of simulation, since experimental and analytical approaches are often impractical and intractable, respectively. The reliability of the simulative evaluation is thus paramount to the performance analysis of vehicular networks, and the first distinctive feature that has to be properly accounted for is the mobility of vehicles, i.e., network nodes. Notwithstanding the improvements that vehicular mobility modeling has undergone over the last decade, no vehicular mobility dataset is publicly available today that captures both the macroscopic and microscopic dynamics of road traffic over a large urban region. In this paper, we present a realistic synthetic dataset, covering 24 hours of car traffic in a 400-km2 region around the city of Köln, in Germany. We describe the generation process and outline how the dataset improves the traces currently employed for the simulative evaluation of vehicular networks. We also show the potential impact that such a comprehensive mobility dataset has on the network protocol performance analysis, demonstrating how incomplete representations of vehicular mobility may result in over-optimistic network connectivity and protocol performance.
Trullols Cruces, Oscar; Fiore, Marco; Barcelò Ordinas, José María IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks p. 6583402-1-6583402-9 DOI: 10.1109/WoWMoM.2013.6583402 Presentation's date: 2013-07 Presentation of work at congresses
The large-scale adoption of vehicle-to-vehicle (V2V) communication technologies risks to significantly widen the attack surface available to mobile malware targeting critical automobile operations. Given that outbreaks of vehicular computer worms self-propagating through V2V links could pose a significant threat to road traffic safety, it is important to understand the dynamics of such epidemics and to prepare adequate countermeasures. In this paper we perform a comprehensive characterization of the infection process of variously behaving vehicular worms on a road traffic scenario of unprecedented scale and heterogeneity. We then propose a simple yet effective data-driven model of the worm epidemics, and we show how it can be leveraged for smart patching infected vehicles through the cellular network in presence of a vehicular worm outbreak.
Reineri, Massimo; Casetti, Claudio; Chiasserini, Carla-Fabiana; Fiore, Marco; Trullols Cruces, Oscar; Barcelò Ordinas, José María DOI: 10.4018/978-1-4666-2223-4.ch005 Date of publication: 2012-10-01 Book chapter
Trullols Cruces, Oscar; Fiore, Marco; Barcelò Ordinas, José María IEEE transactions on mobile computing Vol. 11, num. 48, p. 663-678 DOI: 10.1109/TMC.2011.100 Date of publication: 2012-04 Journal article
In this letter, we compute the exact probability that a receiver obtains N linearly independent packets among K ≥ N received packets, when the sender/s use/s random linear network coding over a Galois Field of size q. Such condition maps to the receiver's capability to decode the original information, and its mathematical characterization helps to design the coding so to guarantee the correctness of the transmission. Our formulation represents an improvement over the current upper bound for the decoding probability, and provides theoretical grounding to simulative results in the literature.
Trullols Cruces, Oscar; Morillo Pozo, Julian David; Barcelò Ordinas, José María; Garcia Vidal, Jorge IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks p. 1-9 DOI: 10.1109/WoWMoM.2011.5986464 Presentation of work at congresses
Wireless nodes such as smart-phones in which the WiFi wireless card is continuously on, consume battery energy in just a few hours. Moreover, in many scenarios, an always-on wireless card is useless because there is often no need for transmission and/or reception. This fact is exacerbated in Delay/Disruptive Tolerant Network (DTN) environments, in which nodes exchange Delay Tolerant Objects (DTO) when they meet. Power Saving Management (PSM) techniques enable the lifetime of the nodes to be extended. This paper analyses the trade-offs that appear when wireless nodes periodically turn off the wireless card in order to save battery in DTN environments. The paper shows the conditions in which a node can switch off the battery without impacting the peer-to-peer contact probability, and those in which this contact probability is decreased. For example, it is shown that node lifetime can be doubled while keeping the peer-to-peer contact probability equal to one. But, further increase of the node lifetime quickly decreases peer-to-peer contact probability. Finally, the impact of power savings in DTO dissemination time is also analyzed.
Meyer, Harald; Trullols Cruces, Oscar; Hess, Andrea; Hummel, Karin Anna; Barcelò Ordinas, José María; Casetti, Claudio; Karlsson, Gunnar IEEE IFIP Annual Mediterranean Ad Hoc Networking Workshop p. 95-102 DOI: 10.1109/Med-Hoc-Net.2011.5970499 Presentation of work at congresses
VANET applications are often providing street traffic information to vehicles and drivers, regarding, for instance, traffic conditions and parking space availability. This information influences in turn the driving behavior in real-world settings.
Mobility models used in current VANET simulations are mostly ignoring this feedback entirely. In cases the feedback is included, it is mainly based on ad-hoc approaches with lack of generality. With this paper, we contribute to the investigation of such feedback loops within VANETs by describing the levels at which
feedback loops can be introduced, i.e., on strategic, tactical, and operational levels of mobility. We further describe how feedback
loops can be introduced in arbitrary mobility models and in particular in elementary mobility models. We exemplify our
approach by introducing two types of feedback loops for the Manhattan Mobility model, the Random Trip model, and the
Constrained Random Trip model. One feedback loop represents points of interest attracting vehicles, such as free parking spaces attracting vehicles searching for parking. The other feedback loop focuses on repelling vehicles, such as a traffic jam.
We discuss the impacts of the feedback in terms of the mobility metrics: vehicle density per area, number of direction changes, and intensity of direction changes. Furthermore, we discuss the effects in terms of information availability and delays of
transmission in an opportunistic vehicular network.
Trullols Cruces, Oscar; Morillo Pozo, Julian David; Barcelò Ordinas, José María International Symposium on Applied Sciences in Biomedical and Communication Technologies p. 1-564 DOI: 10.1145/2093698.2093828 Presentation's date: 2011 Presentation of work at congresses
Epidemic modeling has been used to analyze many disciplines such as biology, ecology and medicine. In the last years, it also has been applied to networking paradigms such as social networks, virus spreading in Internet and lastly to opportunistic networking in mobile networks. In this paper we revise some of the facts of epidemic modeling in mobile networks and use these models to analyze the impact of adding infrastructure to sparse opportunistic mobile networks. We show how the position in which infrastructure is placed takes an important impact in the dissemination delay.
Trullols Cruces, Oscar; Barcelò Ordinas, José María; Fiore, Marco; Casetti, Claudio; Chiasserini, Carla-Fabiana IEEE International Conference on Wireless and Mobile Computing, Networking and Communications p. 154-160 DOI: 10.1109/WiMob.2009.35 Presentation's date: 2009-10-14 Presentation of work at congresses
We consider that a given number of Dissemination Points (DPs) have to be deployed for disseminating information
to vehicles travelling in an urban area. We formulate our problem as a Maximum Coverage Problem (MCP) so as to maximize the number of vehicles that get in contact with
the DPs and as a second step with a sufficient amount of time. Since the MCP is NP-hard, we solve it though heuristic
algorithms. Evaluation of the proposed solutions in a realistic urban environment shows how knowledge of vehicular mobility
plays a major role in achieving an optimal coverage of mobile users, and that simple heuristics provide near-optimal results
even in large-scale scenarios.
Trullols Cruces, Oscar; Barcelò Ordinas, José María; Fiore, Marco; Casetti, Claudio; Chiasserini, Carla-Fabiana Euro-NF Workshop on Wireless and Mobility p. 1-6 Presentation's date: 2009-09-22 Presentation of work at congresses
We consider that a given number of Dissemination Points (DPs) have to be deployed for disseminating information
to vehicles travelling in an urban area. We formulate our problem as a Maximum Coverage Problem (MCP) so as to maximize the number of vehicles that get in contact with the
DPs. Since the MCP is NP-hard, we solve it though heuristic algorithms. Evaluation of the proposed solutions in a realistic urban environment shows how knowledge of vehicular mobility plays a major role in achieving an optimal coverage of mobile users, and that simple heuristics provide near-optimal results even in large-scale scenarios.
Trullols Cruces, Oscar; Morillo Pozo, Julian David; Barcelò Ordinas, José María; Garcia Vidal, Jorge IEEE International Conference on Communications p. 1-6 DOI: 10.1109/ICC.2009.5198586 Presentation's date: 2009-06-17 Presentation of work at congresses
Vehicular Ad Hoc Networks are networks
characterized by intermittent connectivity and rapid changes in their topology. This paper addresses car-to-road communications
in which vehicles use Access Points (AP) in a Delay Tolerant Network architecture. Results show how the combination of a
Delay-Cooperative ARQ mechanism reduces packet losses and in conjunction with a Carry-and-Forward cooperative mechanism
improves performance parameters in terms of total file transfer delay and number of AP needed to download files.
Trullols Cruces, Oscar; Morillo Pozo, Julian David; Barcelò Ordinas, José María; Garcia Vidal, Jorge EuroNF Workshop on Wireless and Mobility Presentation's date: 2008-10-24 Presentation of work at congresses
This paper evaluates a Cooperative ARQ protocol to be used in delay-tolerant vehicular networks. The scenario consists in cars downloading information from Access Points along a road. The key difference between proposed Cooperative ARQ protocols is when the cooperation takes place. Simply C-ARQ cooperation occurs in a packet-by-packet basis. In this proposal, that we call DC-ARQ (Delayed Cooperative ARQ), the cooperation is delayed until cars are out of the coverage area of the Access Point. The scheme has been evaluated through simulations. A comparison of DC-ARQ with a
baseline case in which no cooperation is used has been performed under different vehicle densities scenarios.
Morillo Pozo, Julian David; Trullols Cruces, Oscar; Barcelò Ordinas, José María; Garcia Vidal, Jorge International Conference on Distributed Computing Systems p. 192-197 DOI: 10.1109/ICDCS.Workshops.2008.58 Presentation's date: 2008-06-20 Presentation of work at congresses
This paper proposes a Cooperative ARQ protocol to be used in delay-tolerant vehicular networks. The proposed scheme has been implemented and evaluated through an experimental testbed, showing that packet
losses in transmissions from an access point to cars can be reduced to the half without any cost as long as cooperation takes place on areas where connectivity with access points is not present. In these areas, cars
in a platoon recover from other cars packets that they have failed to receive from the access point.
Morillo Pozo, Julian David; Barcelò Ordinas, José María; Trullols Cruces, Oscar; Garcia Vidal, Jorge EuroFGI Workshop on Wireless and Mobility Presentation's date: 2008-01-16 Presentation of work at congresses
This paper proposes a Cooperative ARQ protocol to be used in delay-tolerant vehicular networks. The proposed scheme
has been implemented and evaluated through an experimental testbed, showing that packet losses in transmissions from an access point to cars can be reduced to the half without any cost as long as cooperation takes place on areas where connectivity with access points is not present. In these areas, cars in a platoon recover from other cars packets that they have failed to receive from the access point.