A feedback based solution to emulate hidden terminals in wireless networks

Mobile wireless emulation allows the test of real applications and transport protocols over a wired network mimicking the behavior of a mobile wireless network (nodes mobility, radio signal propagation and specific communication protocols). Two-stage IP-level network emulation consists in using a dedicated offline simulation stage to compute an IPlevel emulation scenario, which is played subsequently in the emulation stage. While this type of emulation allows the use of accurate computation models together with a large number of nodes, it currently does not allow to deal with dynamic changes of the real traffic. This lack of reactivity makes it impossible to emulate specific wireless behaviors such as hidden terminals in a realistic way. In this paper we address the need to take into account the real traffic during the emulation stage and we introduce a feedback mechanism. During the simulation several emulation scenarios are computed, each scenario corresponding to alternative traffic conditions related to e.g. occurrence or not of hidden terminals. During the emulation stage, the traffic is observed and the currently played emulation scenario can be changed according to specific network conditions. We propose a solution based on multiple scenarios generation, traffic observers and a feedback mechanism to add a trafficbased dynamic behavior to a two-stage emulation platform. The solution will be illustrated with a simple experiment based on hidden terminals

Two-stage wireless network emulation

Testing and deploying mobile wireless networks and applications are very challenging tasks, due to the network size and administration as well as node mobility management. Well known simulation tools provide a more flexible environment but they do not run in real time and they rely on models of the developed system rather than on the system itself. Emulation is a hybrid approach allowing real application and traffic to be run over a simulated network, at the expense of accuracy when the number of nodes is too important. In this paper, emulation is split in two stages : first, the simulation of network conditions is precomputed so that it does not undergo real-time constraints that decrease its accuracy ; second, real applications and traffic are run on an emulation platform where the precomputed events are scheduled in soft real-time. This allows the use of accurate models for node mobility, radio signal propagation and communication stacks. An example shows that a simple situation can be simply tested with real applications and traffic while relying on accurate models. The consistency between the simulation results and the emulated conditions is also illustrated

W-NINE: a two-stage emulation platform for mobile and wireless systems

More and more applications and protocols are now running on wireless networks. Testing the implementation of such applications and protocols is a real challenge as the position of the mobile terminals and environmental effects strongly affect the overall performance. Network emulation is often perceived as a good trade-off between experiments on operational wireless networks and discrete-event simulations on Opnet or ns-2. However, ensuring repeatability and realism in network emulation while taking into account mobility in a wireless environment is very difficult. This paper proposes a network emulation platform, called W-NINE, based on off-line computations preceding online pattern-based traffic shaping. The underlying concepts of repeatability, dynamicity, accuracy and realism are defined in the emulation context. Two different simple case studies illustrate the validity of our approach with respect to these concepts

Trends on integrating framework of applications or data

International audienceA lot of telemedicine applications are nowadays tested in medical situation, but the challenges underlined through the best papers selection deals on the ability of proposing integrative framework for application or data in order to handle efficiency of health and clinical management

Définition et mise en oeuvre d'une solution d'émulation de réseaux sans fil

Pour évaluer et tester des applications et des protocoles de transport dans un réseau sans fil, il existe différentes méthodes parmi lesquelles l'émulation, un compromis entre le test en environnement réel et la simulation. Dans cette thèse nous présentons W-NINE une nouvelle solution d'émulation centralisée de niveau IP pour les réseaux sans fil qui s'intéresse à trois points : la précision des modèles utilisés, la préservation de leur comportement dynamique et la reproduction fidèle d'une même expérience plusieurs fois de suite. Pour cela, nous proposons une architecture originale utilisant une phase de simulation préalable à l'émulation et des observateurs au cours de l'émulation pour tenir compte des effets liés au trafic circulant dans le réseau sans fil. Une évaluation expérimentale de la plate-forme W-NINE a été menée pour montrer la concordance des résultats obtenus lors de chaque phase ainsi que l'amélioration du réalisme obtenu grâce à l'utilisation d'observateurs de trafic. ABSTRACT : In wireless networks, several solutions are possible to test and evaluate transport protocols or applications among which there is emulation, a compromise between live test and simulation. In this thesis, we present W-NINE a new fully centralized wireless emulation solution which works at the IP level. W-NINE focuses on three points : the precision of models used, the preservation of their dynamic behaviour and the ability to precisely reproduce an experiment from a run to another. To deal with these three aspects, an original architecture that uses a simulation phase prior to emulation is proposed. Moreover, we introduce network observers which are used to deal with trafic-based effects that can occur in a wireless network (e.g. hidden terminals). An experimental evaluation of W-NINE has been made to show the viability of this approach by comparing results obtained during the simulation phase and the emulation phase and to show the increase in realism obtained by network observers

Secure and Trusted Execution:Past, Present, and Future - A Critical Review in the Context of the Internet of Things and Cyber-Physical Systems

International audienc

DÉFINITION ET MISE EN OEUVRE D'UNE SOLUTION<br />D'ÉMULATION DE RÉSEAUX SANS FIL

In wireless networks, several solutions are possible to test and evaluate transport protocolsor applications among which there is emulation, a compromise between live test and simulation.In this thesis, we present W-NINE a new fully centralized wireless emulation solutionwhich works at the IP level. W-NINE focuses on three points: the precision of models used, thepreservation of their dynamic behaviour and the ability to precisely reproduce an experimentfrom a run to another. To deal with these three aspects, an original architecture that uses asimulation phase prior to emulation is proposed. Moreover, we introduce network observerswhich are used to deal with trace-based effects that can occur in a wireless network (e.g. hiddenterminals).An experimental evaluation of W-NINE has been made to show the viability of thisapproach by comparing results obtained during the simulation phase and the emulation phase andto show the increase in realism obtained by network observers.Pour évaluer et tester des applications et des protocoles de transport dans un réseau sansfil, il existe différentes méthodes parmi lesquelles l'émulation, un compromis entre le test enenvironnement réel et la simulation.Dans cette thèse nous présentons W-NINE une nouvelle solution d'émulation centraliséede niveau IP pour les réseaux sans _l qui s'intéresse à trois points : la précision des modèlesutilisés, la préservation de leur comportement dynamique et la reproduction fidèle d'une mêmeexpérience plusieurs fois de suite. Pour cela, nous proposons une architecture originale utilisantune phase de simulation préalable à l'émulation et des observateurs au cours de l'émulation pourtenir compte des effets liés au trafic circulant dans le réseau sans fil.Une évaluation expérimentale de la plate-forme W-NINE a été menée pour montrer laconcordance des résultats obtenus lors de chaque phase ainsi que l'amélioration du réalismeobtenu grâce à l'utilisation d'observateurs de trafic

Définition et mise en oeuvre d'une solution d'émulation de réseaux sans fil

TOULOUSE-ENSEEIHT (315552331) / SudocVILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

A 2015 Medical Informatics Perspective on Health and Clinical Management: Will Cloud and Prioritization Solutions Be the Future of Health Data Management?

International audienceObjectives: Summarize current excellent research and trends in the field of Health and Clinical management. Methods: Synopsis of the articles selected for the IMIA Yearbook 2015Results: Three papers from international peer-reviewed journals have been selected for the Health and Clinical Management section.Conclusion: Telemedicine is still very active in Health and clinical management, but the new tendencies on which we focus this year were firstly the introduction of cloud for health data management, with some specific security problems, and secondly an emerging expectation of prioritization tools in health care Management