161 research outputs found

    Simulating Opportunistic Networks: Survey and Future Directions

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    (c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works[EN] Simulation is one of the most powerful tools we have for evaluating the performance of opportunistic networks (OppNets). In this paper, we focus on available tools and mod- els, compare their performance and precision and experimentally show the scalability of different simulators. We also perform a gap analysis of state-of-the-art OppNet simulations and sketch out possible further development and lines of research. This paper is targeted at students starting work and research in this area while also serving as a valuable source of information for experienced researchers.This work was supported in part by the Ministerio de Economia y Competitividad, Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad, Proyectos I+D+I 2014, Spain, under Grant TEC2014-52690-R, in part by the Universidad Laica Eloy Alfaro de Manabi, and in part by the Secretaria Nacional de Educacion Superior, Ciencia, Tecnologia e Innovacion, Ecuador. (Corresponding author: Jens Dede.)Dede, J.; Förster, A.; Hernández-Orallo, E.; Herrera-Tapia, J.; Kuladinithi, K.; Kuppusamy, V.; Manzoni, P.... (2018). Simulating Opportunistic Networks: Survey and Future Directions. IEEE Communications Surveys & Tutorials. 20(2):1547-1573. https://doi.org/10.1109/COMST.2017.2782182S1547157320

    Mecanismos de rede para swarms de drones em ambientes de monitorização aquática

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    With the development of intelligent platforms for environment sensing, drones present themselves as a fundamental resource capable of responding to the widest range of applications. Monitoring aquatic sensing environments is one such application and the communication between them becomes a key aspect for both navigation and sensing tasks. Testing an aquatic environment with a high number of Unmanned Surface Vehicles (USVs) is very costly, requiring a lot of time and resources. Therefore, simulation platforms become elements of great importance . In this dissertation a simulator is developed containing a modular architecture, based on a delay tolerant network, being capable of simulating aquatic environments as similar as possible to real aquatic environments. In addition to the developed simulator, this dissertation presents methods and strategies of cluster formation, allowing the aquatic drones to select, in a distributed way, the gateways of each cluster that will be responsible for forwarding collected data towards the gateway on land. Two gateway selection methods were implemented, one focused on the energy of aquatic drones, and one considering different metrics such as link quality, centrality and energy. The proposed methods were evaluated across several cases and scenarios, with clusters built and changed in a dynamic way, and it was observed that the election of gateways with a method based on several metrics, together with appropriated control strategy, provides a better outcome of the network behaviour throughout the aquatic monitoring tasks.Com o desenvolvimento de plataformas inteligentes que permitem monitorizar vários ambientes, os drones apresentam-se como um recurso fundamental capaz de responder às mais vastas aplicações. A monitorização de meios aquáticos com recurso a drones é uma destas aplicações e a comunicação entre os mesmos torna-se um aspeto fundamental, tanto em tarefas de navegação como em tarefas de sensorização. Testar um ambiente aquático com um elevado número de drones aquáticos é muito caro, requer muito tempo e vários recursos, por isso, plataformas de simulação tornam-se elementos de grande importância. Nesta dissertação é desenvolvido um simulador, com uma arquitetura modular, tendo por base uma rede tolerante a atrasos, sendo capaz de simular ambientes aquáticos o mais semelhante possível a ambientes aquáticos reais. Para além do simulador desenvolvido, esta dissertação propõe métodos e estratégias de formação de clusters de drones, permitindo que os drones aquáticos elejam, de uma forma distribuída, os gateways de cada cluster que serão responsáveis por encaminhar os dados recolhidos pelos drones em direção à estação em terra. Foram implementados dois métodos de eleição de gateway, um focado na energia dos drones aquáticos, e outro capaz de considerar diferentes métricas, tais como a qualidade de ligação, a centralidade e a energia. Os métodos propostos foram avaliados através de vários cenários em que os clusters são construídos e alterados de forma dinâmica, e foi observado que a escolha de gateways com um método baseado em várias métricas, e juntamente com uma estratégia de controlo apropriada, proporciona um melhor comportamento da rede ao longo das tarefas de monitorização aquática.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

    Wireless 802.11 IP Networks and their models in the OMNeT++ simulation tool

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    Bakalárska práca je venovaná zoznámeniu so štandardom IEEE 802.11. V práci sú zhrnuté jeho výhody, nevýhody história a rozdelenie do skupín podža noriem. Vežká pozornosť je venovaná užívatežskému zoznámeniu so simulačným nástrojom OMNeT++ a jeho nadstavbou Inet Framework. Práve táto nadstavba sa podieža na rozšírení simulátoru o podporu modelovania bezdrôtových sietí. Podporuje modely niekožkých protokolov ako sú IP, UDP/TCP, Ethernet, PPP, IPV6, OSPF, RIP, MPLS. Obsahuje už naprogramované API moduly, z ktorých je možné žahko vytvoriť bezdrôtovú IP sieť. V príslušných kapitolách sú popísané programy, ktoré sú potrebné pre správny chod OMNeT++. Časť práce sa zaoberá inštaláciou a nastavením týchto programov pre správnu funkčnosť kompilačného prostredia. V práci sú rozobrané možnosti a spôsoby simulácie bezdrôtových IP sietí, ktorými je možné vytvoriť základný simulačný model reprezentujúci štandard 802.11. V neposlednej rade sú v práci zahrnuté laboratórne úlohy, ktoré obsahujú teoretický úvod k danej problematike. Úlohy sú zamerané na ad-hoc a infraštruktúrny mód. Obsahujú teoretické zoznámenie s problematikou, podrobný návod na tvorenie s vysvetlením a spracované výsledky a výstupy simulácie.The bachelor work concentrates on familiarization with the standard IEEE 802.11. The work summarises the advantages, disadvantages, history and grouping of this standard according to norms. The great attention is paid to a user’s familiarization with the stimulating tool OMNeT++ and its extension Inet Framework. This extension helps to amplify the simulator for a supporting modelling of wireless nets. It supports models of a few protocols such as IP, UDP/TCP, Ethernet, PPP, IPV6, OSPF, RIP, and MPLS. It includes already programmed API modules from which is possible to create easily a wireless IP net.Programmes needed for a proper functioning of the OMNeT++ are described in corresponding paragraphs. A part of work deals with an installation and setting of programmes for accurate functioning of a compiler surrounding. Our work analyzes possibilities and manners of simulation of wireless IP nets which helps to create basic simulation model represented by standard 802.11. There are also included laboratory works in our bachelor work, which includes theoretical introduction to studied issues. Tasks are concentrated on ad-hoc and infrastructure mode. These tasks comprise of theory of problematic, detailed instructions for creating together with explanations, processed results and output of simulation

    Simulation and Evaluation of Wired and Wireless Networks with NS2, NS3 and OMNET++

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    Communication systems are emerging rapidly with the revolutionary growth in terms of networking protocols, wired and wireless technologies, user applications and other IEEE standards. Numbers of industrial as well as academic organizations around the globe are bringing in light new innovations and ideas in the field of communication systems. These innovations and ideas require intense evaluation at initial phases of development with the use of real systems in place. Usually the real systems are expensive and not affordable for the evaluation. In this case, network simulators provide a complete cost-effective testbed for the simulation and evaluation of the underlined innovations and ideas. In past, numerous studies were conducted for the performance evaluation of network simulators based on CPU and memory utilization. However, performance evaluation based on other metrics such as congestion window, throughput, delay, packet delivery ratio and packet loss ratio was not conducted intensively. In this thesis, network simulators such as NS2, NS3 and OMNET++ will be evaluated and compared for wired and wireless networks based on congestion window, throughput, delay, packet delivery and packet loss ratio. In the theoretical part, information will be provided about the wired and wireless networks and mathematical interpretation of various components used for these networks. Furthermore, technical details about the network simulators will be presented including architectural design, programming languages and platform libraries. Advantages and disadvantages of these network simulators will also be highlighted. In the last part, the details about the experiments and analysis conducted for wired and wireless networks will be provided. At the end, findings will be concluded and future prospects of the study will be advised.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

    Distributed Hybrid Simulation of the Internet of Things and Smart Territories

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    This paper deals with the use of hybrid simulation to build and compose heterogeneous simulation scenarios that can be proficiently exploited to model and represent the Internet of Things (IoT). Hybrid simulation is a methodology that combines multiple modalities of modeling/simulation. Complex scenarios are decomposed into simpler ones, each one being simulated through a specific simulation strategy. All these simulation building blocks are then synchronized and coordinated. This simulation methodology is an ideal one to represent IoT setups, which are usually very demanding, due to the heterogeneity of possible scenarios arising from the massive deployment of an enormous amount of sensors and devices. We present a use case concerned with the distributed simulation of smart territories, a novel view of decentralized geographical spaces that, thanks to the use of IoT, builds ICT services to manage resources in a way that is sustainable and not harmful to the environment. Three different simulation models are combined together, namely, an adaptive agent-based parallel and distributed simulator, an OMNeT++ based discrete event simulator and a script-language simulator based on MATLAB. Results from a performance analysis confirm the viability of using hybrid simulation to model complex IoT scenarios.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0487

    Exploiting Map Topology Knowledge for Context-predictive Multi-interface Car-to-cloud Communication

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    While the automotive industry is currently facing a contest among different communication technologies and paradigms about predominance in the connected vehicles sector, the diversity of the various application requirements makes it unlikely that a single technology will be able to fulfill all given demands. Instead, the joint usage of multiple communication technologies seems to be a promising candidate that allows benefiting from characteristical strengths (e.g., using low latency direct communication for safety-related messaging). Consequently, dynamic network interface selection has become a field of scientific interest. In this paper, we present a cross-layer approach for context-aware transmission of vehicular sensor data that exploits mobility control knowledge for scheduling the transmission time with respect to the anticipated channel conditions for the corresponding communication technology. The proposed multi-interface transmission scheme is evaluated in a comprehensive simulation study, where it is able to achieve significant improvements in data rate and reliability

    Improving Message Dissemination in Opportunistic Networks

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    Data transmission has become a need in various fields, like in social networks with the diverse interaction applications, or in the scientific and engineering areas where for example the use of sensors to capture data is growing, or in emergency situations where there is the imperative need to have a communication system to coordinate rescue operations. Wireless networks have been able to solve these issues to a great extent, but what can we do when a fixed supporting infrastructure is not available or becomes inoperative because of saturation? Opportunistic wireless networks are an alternative to consider in these situations, since their operation does not depend on the existence of a telecommunications infrastructure but they provide connectivity through the organized cooperation of users. This research thesis focuses on these types of networks and is aimed at improving the dissemination of information in opportunistic networks analyzing the main causes that influence the performance of data transmission. Opportunistic networks do not depend on a fixed topology but depend on the number and mobility of users, the type and quantity of information generated and sent, as well as the physical characteristics of the mobile devices that users have to transmit the data. The combination of these elements impacts on the duration of the contact time between mobile users, directly affecting the information delivery probability. This thesis starts by presenting a thorough "state of the art" study where we present the most important contributions related to this area and the solutions offered for the evaluation of the opportunistic networks, such as simulation models, routing protocols, simulation tools, among others. After offering this broad background, we evaluate the consumption of the resources of the mobile devices that affect the performance of the the applications of opportunistic networks, both from the energetic and the memory point of view. Next, we analyze the performance of opportunistic networks considering either pedestrian and vehicular environments. The studied approaches include the use of additional fixed nodes and different data transmission technologies, to improve the duration of the contact between mobile devices. Finally, we propose a diffusion scheme to improve the performance of data transmission based on extending the duration of the contact time and the likelihood that users will collaborate in this process. This approach is complemented by the efficient management of the resources of the mobile devices.La transmisión de datos se ha convertido en una necesidad en diversos ámbitos, como en las redes sociales con sus diversas aplicaciones, o en las áreas científicas y de ingeniería donde, por ejemplo, el uso de sensores para capturar datos está creciendo, o en situaciones de emergencia donde impera la necesidad de tener un sistema de comunicación para coordinar las operaciones de rescate. Las redes inalámbricas actuales han sido capaces de resolver estos problemas en gran medida, pero ¿qué podemos hacer cuando una infraestructura de soporte fija no está disponible o estas se vuelven inoperantes debido a la saturación de peticiones de red? Las redes inalámbricas oportunísticas son una alternativa a considerar en estas situaciones, ya que su funcionamiento no depende de la existencia de una infraestructura de telecomunicaciones sino que la conectividad es a través de la cooperación organizada de los usuarios. Esta tesis de investigación se centra en estos tipos de redes oportunísticas y tiene como objetivo mejorar la difusión de información analizando las principales causas que influyen en el rendimiento de la transmisión de datos. Las redes oportunísticas no dependen de una topología fija, sino que dependen del número y la movilidad de los usuarios, del tipo y cantidad de información generada y enviada, así como de las características físicas de los dispositivos móviles que los usuarios tienen para transmitir los datos. La combinación de estos elementos influye en la duración del tiempo de contacto entre usuarios móviles, afectando directamente a la probabilidad de entrega de información. Esta tesis comienza presentando un exhaustivo estudio del ``estado del arte", donde presentamos las contribuciones más importantes relacionadas con esta área y las soluciones existentes para la evaluación de las redes oportunísticas, tales como modelos de simulación, protocolos de enrutamiento, herramientas de simulación, entre otros. Tras ofrecer esta amplia compilación de investigaciones, se evalúa el consumo de recursos de los dispositivos móviles que afectan al rendimiento de las aplicaciones de redes oportunísticas, desde el punto de vista energético así como de la memoria. A continuación, analizamos el rendimiento de las redes oportunísticas considerando tanto los entornos peatonales como vehiculares. Los enfoques estudiados incluyen el uso de nodos fijos adicionales y diferentes tecnologías de transmisión de datos, para mejorar la duración del contacto entre dispositivos móviles. Finalmente, proponemos un esquema de difusión para mejorar el rendimiento de la transmisión de datos basado en la extensión de la duración del tiempo de contacto, y de la probabilidad de que los usuarios colaboren en este proceso. Este enfoque se complementa con la gestión eficiente de los recursos de los dispositivos móviles.La transmissió de dades s'ha convertit en una necessitat en diversos àmbits, com ara en les xarxes socials amb les diverses aplicacions d'interacció, o en les àrees científiques i d'enginyeria, en les quals, per exemple, l'ús de sensors per a capturar dades creix en l'actualitat, o en situacions d'emergència en què impera la necessitat de tenir un sistema de comunicació per a coordinar les operacions de rescat. Les xarxes sense fil han sigut capaces de resoldre aquests problemes en gran manera, però què podem fer quan una infraestructura de suport fixa no està disponible, o bé aquestes es tornen inoperants a causa de la saturació de peticions de xarxa? Les xarxes sense fil oportunistes són una alternativa que cal considerar en aquestes situacions, ja que el funcionament d'aquestes xarxes no depèn de l'existència d'una infraestructura de telecomunicacions, sinó que la connectivitat s'hi aconsegueix a través de la cooperació organitzada dels usuaris. Aquesta tesi de recerca se centra en aquest tipus de xarxes, i té com a objectiu millorar la difusió d'informació en xarxes oportunistes tot analitzant les principals causes que influeixen en el rendiment de la transmissió de dades. Les xarxes oportunistes no depenen d'una topologia fixa, sinó del nombre i la mobilitat dels usuaris, del tipus i la quantitat d'informació generada i enviada, i de les característiques físiques dels dispositius mòbils que els usuaris tenen per a transmetre les dades. La combinació d'aquests elements influeix en la durada del temps de contacte entre usuaris mòbils, i afecta directament la probabilitat de lliurament d'informació. Aquesta tesi comença amb un estudi exhaustiu de l'estat de la qüestió, en què presentem les contribucions més importants relacionades amb aquesta àrea i les solucions oferides per a l'avaluació de les xarxes oportunistes, com ara models de simulació, protocols d'encaminament o eines de simulació, entre d'altres. Després de mostrar aquest ampli panorama, s'avalua el consum dels recursos dels dispositius mòbils que afecten l'acompliment de les aplicacions de xarxes oportunistes, tant des del punt de vista energètic com de la memòria. A continuació, analitzem l'acompliment de xarxes oportunistes considerant tant els entorns de vianants com els vehiculars. Els enfocaments estudiats inclouen l'ús de nodes fixos addicionals i diferents tecnologies de transmissió de dades per a millorar la durada del contacte entre dispositius mòbils. Finalment, proposem un esquema de difusió per a millorar el rendiment de la transmissió de dades basat en l'extensió de la durada del temps de contacte, i de la probabilitat que els usuaris col·laboren en aquest procés. Aquest enfocament es complementa amb la gestió eficient dels recursos dels dispositius mòbils.Herrera Tapia, J. (2017). Improving Message Dissemination in Opportunistic Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86129TESI

    Last mile mobile hybrid optical wireless access network routing enhancement

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    This study focuses on mobile ad hoc networks (MANETs) that support Internet routing protocol imposing stringent resource consumption constraints of Quality of service (QoS). The mobile Internet causes the on-going issue of inefficient use of the MANET resources due to its random nature of wireless environments. In this paper, the new improved architecture of the last mile mobile hybrid optical-wireless access network (adLMMHOWAN) is proposed and designed to tackle the arised issues. The proposed design is based on a unified wireless-wired network solution required the deployment of MANET-based wireless fidelity (WiFi) technology at the wireless front-end and wavelengths division multiplexing passive optical network (WDM PON) at the optical backhaul. The critical performance metrics such as network capacity and energy consumption based on modified AODVUU routing protocol using OMNeT++ software is analyzed with 2 scenarios, namely the number of nodes and mobility speed. This mode of communication results in better QoS network capacity of 47.07% improvement, with 26.85% reduction of lower energy resource consumption for mobile wireless front-end over passive optical network backhaul architecture when compared with the existing work of oRiq scheme that focus on improvement in MANETs

    PERFORMANCE EVALUATION OF WiFi WITH AND WITHOUT QoS

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    Wireless local area networks (WLANs) have been around for a long time but only recently have they become popular. Despite the fact that Wireless LANs have achieved a tremendous amount of growth in recent years, the performance is very poor. Hence, multimedia wireless network QoS support has become one of the most important researches. In order to improve the poor performance of existing system, QoS features and MAC enhancements are needed in the upcoming 802.1 le standard. This project aims to evaluate the performance of Wi-Fi systems with and without QoS, and quantify how well the new enhancement can support applications that require certain QoS guarantees. A thorough research on the IEEE802.11 standards is necessary to the success ofthis project, as well as an immaculate and extensive study on the QoS performance ofthe network. All the studies and evaluation is being done with a simulation using OMNeT++. The project requires knowledge of the WiFi architecture, C++ programming language, setting up simulation of a network in OMNeT++, andthen evaluating theQoS performance
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