In this thesis we have focused in the wireless environment and how to run voice application over it. Conducive environment that makes it possible for the voice services to run in wireless is necessary. As we know this well that wireless is a contemporary technology due to it low cost and its effectiveness, and one major advantage of it is the mobility that is one fell free to move anywhere but have the access to the resource. So this makes wireless networks of great value, we in this thesis have focused on wireless LAN’s. In second part of the thesis we have shed some light on the VoIP showing how it works in the wireless environment. Analysis phase is relatively more important phase then the previous section which shows issues or hindrances in carrying voice over wireless environment. This analysis shows that these issues still prevails and should be addresses and the corresponding results are also discussed and by looking at those results we have derived a summery out of it. Next chapter we firstly tried to explain why we have chosen specific protocols and then showing some graphical representation measurements that are to address the problem based on the work done. We tried to evaluate EDCF and DCF as these play important role in handling real time applications like voice. After that we proposed a scheme through which these effects can be minimized and to enhance the method is necessary to avoid the issues still in effect. / Thesis is Part for Master program in Electrical Engineering with Emphasis on Telecommunication(2007-2009).We have had a very nice time doing this thesis as there was alot of learning. Our examinator was allways there to help us, we are thankfull to Richard for his endless support.

abstract: Contention based IEEE 802.11MAC uses the binary exponential backoff algorithm (BEB) for the contention resolution. The protocol suffers poor performance in the heavily loaded networks and MANETs, high collision rate and packet drops, probabilistic delay guarantees, and unfairness. Many backoff strategies were proposed to improve the performance of IEEE 802.11 but all ignore the network topology and demand. Persistence is defined as the fraction of time a node is allowed to transmit, when this allowance should take into account topology and load, it is topology and load aware persistence (TLA). We develop a relation between contention window size and the TLA-persistence. We implement a new backoff strategy where the TLA-persistence is defined as the lexicographic max-min channel allocation. We use a centralized algorithm to calculate each node's TLApersistence and then convert it into a contention window size. The new backoff strategy is evaluated in simulation, comparing with that of the IEEE 802.11 using BEB. In most of the static scenarios like exposed terminal, flow in the middle, star topology, and heavy loaded multi-hop networks and in MANETs, through the simulation study, we show that the new backoff strategy achieves higher overall average throughput as compared to that of the IEEE 802.11 using BEB. / Dissertation/Thesis / M.S. Computer Science 2013

Les réseaux de capteurs sans-fil sont une nouvelle technologie qui permet de déployer des capteurs hétérogènes et de les faire communiquer sans fil et de façon autonome. Cette capacité nouvelle à surveiller ou instrumenter le monde qui nous entoure ouvre la voie à de nouvelles applications innovantes ou à une évolution majeure d’applications déjà existantes.D’une dizaine de nœuds à plusieurs milliers, les réseaux de capteurs sans fil commencent à conquérir le monde industriel et notre vie quotidienne. Leurs besoins en communications, gestion, génération et stockage de l’énergie, miniaturisation et réduction des coûts ne nécessitent pas seulement de perfectionner les technologies actuelles mais bien d’en inventer de nouvelles. Parmi toutes les applications révolutionnaires des réseaux de capteurs sans fil comme dans la santé, l’environnement, l’industrie et le militaire, l’une des applications les plus transformatrices est la surveillance de structure. La surveillance de structure est l’art de surveiller tout ce qui peut s’abimer, s’user ou tomber en panne. Elle est particulièrement importante dans les domaines des transports et du bâtiment, étant donné que la sécurité des personnes est en jeu. En plaçant aux endroits stratégiques des capteurs sans-fil, il sera possible de prévoir et de prévenir la défaillance d’un pont, l’usure d’un avion ou d’un train ou la déformation d’un bâtiment. La surveillance de structure permet de prévenir les pannes et les défaillances, de réduire les coûts de maintenance et d’améliorer les performances. C’est un processus complexe qui implique plusieurs technologies : des capteurs, la transmission de l’information et l’analyse des données. La nature (accéléromètre, gyroscope, jauge de contrainte, température, pression, fuite, givre, etc. . .), la position ainsi que le nombre de capteurs sont dictés et dépendants des besoins de l’analyse de la structure qui doit être effectuée. De ce fait, les contraintes imposées au système de transmission de données sans fil, afin d’offrir une couverture suffisante de la structure de l’appareil avec plusieurs centaines voire plusieurs milliers de capteurs que leur localisation rendra difficile d’accès, nécessitent des nouvelles innovations en matière d’efficacité énergétique et de performance de communication. Ce travail s’intéresse à la conception et l’implémentation d’un système de transmission de données dans un réseau de capteurs sans-fil. Après une présentation des exigences du système de surveillance de structure aéronautique, l’architecture générale du système de surveillance est décrite. Une couche physique spécifique à haute efficacité énergétique basée sur l’Impulse-Radio UltraWide Band a été conçue. Les designs complets de l’émetteur et du récepteur IR-UWB sont présentés ainsi que l'optimisation du codage canal par rapport à la consommation énergétique. Une couche MAC spécifique permettant un nombre important de nœuds et une efficacité énergétique élevée basée sur du TDMA reconfigurable a été conçue. Plusieurs prototypes ont été implémentés pour valider la conception et démontrer les performances. Ces implémentation utilise des techniques avancées d’optimisation de la consommation énergétique et de reconfigurabilité afin de répondre aux exigences des réseaux de capteurs sans-fil. Des simulations ASIC permettent également de prévoir que ce système permettra de supporter des débits applicatifs de plusieurs centaines de mégabits par seconde, tout en permettant à plusieurs dizaines de nœuds de communiquer. Les performances énergétiques de ce système de communication sont aujourd’hui à l’état de l’art. Enfin, cette technologie de communication sans-fil a été intégrée dans un système complet de deux nœuds capteurs et d’un routeur dans un démonstrateur FPGA / Wireless Sensor Networks (WSN) is an emerging technology which allows deploying wireless communicating autonomous heterogenous sensors. This monitoring capability paves the way for new innovative applications or breakthrough evolution of existing ones. WSN have started to change the industry and our daily lives. Their communication, energy, miniaturization and cost requirements cannot be met by evolutions of current technologies but will require new innovations.Among health, environment, industrial and military applications for WSN, one of the most revolutionary is Structural Health Monitoring (SHM). SHM is the art of monitoring anything which can wear, break down or be damaged. It is of utmost importance in safety sensitive domains such as the transport and construction industries.By placing sensors in carefully chosen locations, SHM will allow failure prediction, cost reduction and improved performance of bridges, planes, building or engines.The tens to thousands of sensors and the huge amount of data generated places a strong burden on the wireless communication of the nodes, which cannot be satisfied with today’s technology. This work presents the design and implementation works such a wireless communication system.Following a presentation of the context and requirement of this work, a general description of the SHM system is given. A specific highly energy efficient physical layer based on Impulse-Radio UltraWide Band (IR-UWB) has been designed.The complete IR-UWB transmitter and receiver are detailed, including the energy efficiency optimized channel coding. A specific Medium Access Control (MAC) layer allowing a large number of communicating nodes based on reconfigurableTime Division Multiple Access (TDMA) was designed. Several prototypes of this system have been implemented to prove feasibility and performance. These implementations employ advanced energy consumption reduction and reconfigurability techniques to answer WSN communication challenges. An ASIC implementation simulation has demonstrated hundreds of megabits per second data rate at state of the art energy efficiency

In modern society, security has become an increasingly important subject, as technologyhas become an integrated part of everyday life. The security of a system can be tested withthe help of fuzzing, where incoming messages to the system are altered. In this thesis, afuzzer was developed targeting an E-UTRAN Node B (eNB) in the Long-Term Evolution(LTE) landscape. The eNB is current prototype and is from the company Ericsson. Thefuzzer is particularly designed for testing the Medium Access Control (MAC) layer of theeNB. The fuzzer uses a genetic method where all of the fuzzer’s flags (the R, F2, E, LCID, Fand L flags) are triggered during the fuzzing period. Depending on the output of the firstgeneration of fuzzed values, new values are generated either by choosing a value close tothe original value, or by choosing a value that belong to the same subgroup as the originalvalue. Four test cases are made, where first test case is the base line of the program and theother three test cases fuzzes the eNB, using different parts of the fuzzer. The results show that depending on which parts of the fuzzer are used, the connectionbecomes different. For test two and three, the connection became increasingly unstable andmore data was present in the connection. Test case four did not however deviate so muchfrom the baseline, if compared to test two and three.

In recent years, Multi-hop Wireless Networks (MHWNs) have experienced an explosion of deployment due to the increasing demand for continuous connectivity regardless of the physical location. Internet predominant transport protocols, i.e. Transmission Control Protocol (TCP), face performance degradation in MHWNs because of the high loss and link failure rates. Several solutions have been proposed which are based on network state estimation or use information from MAC layer (called metrics) in a cross-layer manner to better comprehend the network state. The first part of this thesis provides a survey and comprehensive definition of common metrics from Physical, MAC, Network and Transport layers and thus provides a multi-criteria and hierarchical classification. After that, the effectiveness in reflecting network information of MAC metrics is also investigated in a systematic way by simulating various network situations and measuring the MAC metrics. Thus, the good MAC metric for congestion control which is coupled with the network contention level and the medium induced losses will be found out. From the results of the effectiveness study, new rate control schemes for transport protocols are proposed which adapt efficiently the source bit rate depending on the network condition provided by some MAC metrics. Through an extensive set of simulations, the performance of the proposed rate control schemes in MHWNs is investigated thoroughly with several network situations.

As camadas de enlace empregadas em redes sem fio de baixo custo e desempenho limitado, como as redes de sensores sem fio, são implementadas segundo o padrão IEEE 802.15.4. Prever o desempenho deste padrão é importante para analisar a viabilidade e o desempenho esperado de projetos envolvendo esse tipo de rede. Constatou-se que trabalhos anteriores com esse objetivo são incompletos no tocante às métricas aferidas e tem foco no cálculo de probabilidades, o que não faz parte da especificação do padrão. Assim, o objetivo deste trabalho foi projetar e implementar um modelo comportamental do padrão IEEE 802.15.4, cujos parâmetros possam ser facilmente alterados e que seja capaz de aferir as principais métricas de uma rede: vazão, taxa de entrega, atraso e gasto de energia. Os objetivos foram cumpridos com a validação do modelo perante simulação com o NS2. Além disso, o modelo foi utilizado para estudar a variação dos parâmetros aMaxFrameRetries, macMaxCSMABackos, initialCW e aUnitBackoPeriod do padrão IEEE 802.15.4, para estudar cenários em que os nós possuem tráfego assimétrico e cenários com diferentes relações de tamanho e taxa de chegada de pacotes, mantendo a taxa de bits constante. / Low cost and performance constrained wireless networks, such as wireless sensor networks, employ IEEE 802.15.4 standard as its MAC layer. Foreseeing this standard\'s performance is essential to analyze the feasibility and expected metrics results of these networks projects. It was observed that previous works with that aim are both incomplete regarding metrics of interest and focus on probability calculation, which is not part of the standard specication. Thus, the objective of this work is to project and implement a behavioral IEEE 802.15.4 standard model, which parameters may be easily set and that covers the main metrics of interest: throughput, delivery rate, delay and energy. The objectives were achieved, with model validation against NS2 simulations. Furthermore, the model was employed to analyze the performance variation caused by the parameters aMaxFrameRetries, macMaxCSMABackos, initialCW and aUnitBackoPeriod from the IEEE 802.15.4 standard and also scenarios with asymmetric trac conditions and packet size and arrival rate variations, maintaining a constant bitrate.

As camadas de enlace empregadas em redes sem fio de baixo custo e desempenho limitado, como as redes de sensores sem fio, são implementadas segundo o padrão IEEE 802.15.4. Prever o desempenho deste padrão é importante para analisar a viabilidade e o desempenho esperado de projetos envolvendo esse tipo de rede. Constatou-se que trabalhos anteriores com esse objetivo são incompletos no tocante às métricas aferidas e tem foco no cálculo de probabilidades, o que não faz parte da especificação do padrão. Assim, o objetivo deste trabalho foi projetar e implementar um modelo comportamental do padrão IEEE 802.15.4, cujos parâmetros possam ser facilmente alterados e que seja capaz de aferir as principais métricas de uma rede: vazão, taxa de entrega, atraso e gasto de energia. Os objetivos foram cumpridos com a validação do modelo perante simulação com o NS2. Além disso, o modelo foi utilizado para estudar a variação dos parâmetros aMaxFrameRetries, macMaxCSMABackos, initialCW e aUnitBackoPeriod do padrão IEEE 802.15.4, para estudar cenários em que os nós possuem tráfego assimétrico e cenários com diferentes relações de tamanho e taxa de chegada de pacotes, mantendo a taxa de bits constante. / Low cost and performance constrained wireless networks, such as wireless sensor networks, employ IEEE 802.15.4 standard as its MAC layer. Foreseeing this standard\'s performance is essential to analyze the feasibility and expected metrics results of these networks projects. It was observed that previous works with that aim are both incomplete regarding metrics of interest and focus on probability calculation, which is not part of the standard specication. Thus, the objective of this work is to project and implement a behavioral IEEE 802.15.4 standard model, which parameters may be easily set and that covers the main metrics of interest: throughput, delivery rate, delay and energy. The objectives were achieved, with model validation against NS2 simulations. Furthermore, the model was employed to analyze the performance variation caused by the parameters aMaxFrameRetries, macMaxCSMABackos, initialCW and aUnitBackoPeriod from the IEEE 802.15.4 standard and also scenarios with asymmetric trac conditions and packet size and arrival rate variations, maintaining a constant bitrate.

No description available.

Les Wireless Body Area (WBAN) sont une technologie de réseau sans fil basée sur les radio-fréquences qui consiste à interconnecter sur, autour ou dans le corps humain de minuscules dispositifs pouvant effectuer des mesures (capteurs). Ces réseaux sont considérés comme les plus critiques dans les réseaux de capteurs sans fil. Ils sont basés sur des architectures de réseaux auto-organisés. Chacun des capteurs corporels reçoit ou envoie des paquets du ou au coordinateur du réseau. Ce dernier est responsable de l'ordonnancement des tâches pour l'ensemble des noeuds fils. L'ordonnancement dans les WBAN nécessite un mécanisme dynamique et adaptatif pour gérer les cas d'urgence qui peuvent se produire et permet ainsi d'améliorer les paramètres les plus importants comme la qualité de la transmission, le temps de réponse, le débit, le taux de paquets délivres, etc.Dans ces travaux de thèse, nous avons proposé trois techniques d'ordonnancement qui sont : la méthode semi-dynamique; la méthode dynamique et la méthode basée sur la priorité. De plus, une étude sur les plateformes WBAN est présentée. Dans cette étude, nous avons proposé une classification et une évaluation qualitative des plateformes déjà existantes. Nous avons aussi étudier les modèles de mobilité en proposant une architecture permettant de les décrire. Nous avons aussi mis en place une procédure de diagnostique afin de détecter rapidement des maladies épidémiques dangereuses. Par la suite, ces différentes propositions ont été validées en utilisant deux méthodes afin de vérifier leur faisabilité. Ces méthodes sont la simulation avec OPNET et l'implémentation réelle sur des capteurs TelosB et TinyOS. / The Wireless Body Area Network (WBAN) is the most critical field when considering Wireless Sensor Networks (WSN). It must be a self-organizing network architecture, meaning that it should be able to efficiently manage all network architecture requirements. The WBAN usually contains at least two or more body sensors. Each body sensor sends packets to or receives packets from the Personal Area Network Coordinator (PANC). The PANC is responsible for scheduling its child nodes' tasks. Scheduling tasks in the WBAN requires a dynamic and an adaptive process in order to handle cases of emergency that can occur with a given patient. To improve the most important parameters of a WBAN, such as quality link, response time, throughput, the duty-cycle, and packet delivery, we propose three scheduling processes: the semi-dynamic, dynamic, and priority-based dynamic scheduling approaches.In this thesis, we propose three task scheduling techniques, Semi-Dynamic Scheduling (SDS), Efficient Dynamic Scheduling (EDS) and High Priority Scheduling (HPS) approaches. Moreover, a comprehensive study has been performed for the WBAN platforms by classifying and evaluating them. We also investigate the mobility model for the WBANs by designing an architecture that describe this model. In addition, we detail a diagnosis procedure by using classification methods in order to solve very sensitive epidemic diseases. Then, our proposals have been validated using two techniques to check out the feasibility of our proposals. These techniques are simulation scenarios using the well-known network simulator OPNET and real implementations over TelosB motes under the TinyOS system.

No description available.