The research initiatives addressed in this thesis are geared towards improving the performance of passive optical networks through the development of advanced dynamic bandwidth allocation protocols. In particular, the aim of the research undertaken is to enhance the quality of service offered by standard passive optical networks with reduced network costs. To that extent, a dynamic multi-wavelength protocol has been developed to increase the network upstream bandwidth and introduce multiple service levels to a fibre to the home-based giga-bit passive optical network. Simulation results have confirmed the reduction of the mean packet delay by adjusting the ITU-T standard G984 giga-bit passive optical network frame format by means of the introduction of extended wavelength band overlay based on the ITU-T Coarse- Wavelength Division Multiplexing grid to support the multi-wavelength functionality. To evaluate the multi-wavelength upstream operation of the newly implemented models in OPNET, 2-dimensional Dynamic Bandwidth Allocation algorithms have been introduced to manage the network resources in both the time and wavelength domains. Furthermore, the enhanced traffic allocation among the supported wavelengths in new protocol confirmed a performance improvement in the network total capacity and the mean packet delay, which demonstrates the network reliability and improves the quality of the provided service according to the subscriber service level agreement, with a minimum guaranteed bandwidth of 100 Mbit/s to fulfil applications and associated bandwidth requirements for the next generation access network.

In this thesis, the channel assignment and routing problems have been investigated for both cooperative and competitive Wireless Mesh networks (WMNs). A dynamic and distributed channel assignment scheme has been proposed which generates the network topologies ensuring less interference and better connectivity. The proposed channel assignment scheme is capable of detecting the node failures and mobility in an efficient manner. The channel monitoring module precisely records the quality of bi-directional links in terms of link delays. In addition, a Quality of Service based Multi-Radio Ad-hoc On Demand Distance Vector (QMR-AODV) routing protocol has been devised. QMR-AODV is multi-radio compatible and provides delay guarantees on end-to-end paths. The inherited problem of AODV’s network wide flooding has been solved by selectively forwarding the routing queries on specified interfaces. The QoS based delay routing metric, combined with the selective route request forwarding, reduces the routing overhead from 24% up to 36% and produces 40.4% to 55.89% less network delays for traffic profiles of 10 to 60 flows, respectively. A distributed channel assignment scheme has been proposed for competitive WMNs, where the problem has been investigated by applying the concepts from non-cooperative bargaining Game Theory in two stages. In the first stage of the game, individual nodes of the non-cooperative setup is considered as the unit of analysis, where sufficient and necessary conditions for the existence of Nash Equilibrium (NE) and Negotiation-Proof Nash Equilibrium (N-PNE) have been derived. A distributed algorithm has been presented with perfect information available to the nodes of the network. In the presence of perfect information, each node has the knowledge of interference experience by the channels in its collision domain. The game converges to N-PNE in finite time and the average fairness achieved by all the nodes is greater than 0.79 (79%) as measured through Jain Fairness Index. Since N-PNE and NE are not always a system optimal solutions when considered from the end-nodes prospective, the model is further extended to incorporate non-cooperative end-users bargaining between two end user’s Mesh Access Points (MAPs), where an increase of 10% to 27% in end-to-end throughput is achieved. Furthermore, a non-cooperative game theoretical model is proposed for end-users flow routing in a multi-radio multi-channel WMNs. The end user nodes are selfish and compete for the channel resources across the WMNs backbone, aiming to maximize their own benefit without taking care for the overall system optimization. The end-to-end throughputs achieved by the flows of an end node and interference experienced across the WMNs backbone are considered as the performance parameters in the utility function. Theoretical foundation has been drawn based on the concepts from the Game Theory and necessary conditions for the existence of NE have been extensively derived. A distributed algorithm running on each end node with imperfect information has been implemented to assess the usefulness of the proposed mechanism. The analytical results have proven that a pure strategy Nash Equilibrium exists with the proposed necessary conditions in a game of imperfect information. Based on a distributed algorithm, the game converges to a stable state in finite time. The proposed game theoretical model provides a more reasonable solution with a standard deviation of 2.19Mbps as compared to 3.74Mbps of the random flow routing. Finally, the Price of Anarchy (PoA) of the system is close to one which shows the efficiency of the proposed scheme.

The explosive demand for multimedia and fast transmission of continuous media on wireless networks means the simultaneous existence of traffic requiring different qualities of service (QoS). In this thesis, several efficient algorithms have been developed which offer several QoS to the end-user. We first look at a request TDMA/CDMA protocol for supporting wireless multimedia traffic, where CDMA is laid over TDMA. Then we look at a hybrid push-pull algorithm for wireless networks, and present a generalized performance analysis of the proposed protocol. Some of the QoS factors considered include customer retrial rates due to user impatience and system timeouts and different levels of priority and weights for mobile hosts. We have also looked at how customer impatience and system timeouts affect the QoS provided by several queuing and scheduling schemes such as FIFO, priority, weighted fair queuing, and the application of the stretch-optimal algorithm to scheduling.

High availability, cost effectiveness and ease of application deployment have accelerated the adoption rate of cloud computing. This fast proliferation of cloud computing promotes the rapid development of large-scale infrastructures. However, large cloud datacenters (DCs) require infrastructure, design, deployment, scalability and reliability and need better management techniques to achieve sustainable design benefits. Resources inside cloud infrastructures often operate at low utilization, rarely exceeding 20-30%, which increases the operational cost significantly, especially due to energy consumption. To reduce operational cost without affecting quality of service (QoS) requirements, cloud applications should be allocated just enough resources to minimize their completion time or to maximize utilization.  The focus of this thesis is to enable resource-efficient and performance-aware cloud infrastructures by addressing above mentioned cost and performance related challenges. In particular, we propose algorithms, techniques, and deployment strategies for improving the dynamic allocation of virtual machines (VMs) into physical machines (PMs).  For minimizing the operational cost, we mainly focus on optimizing energy consumption of PMs by applying dynamic VM consolidation methods. To make VM consolidation techniques more efficient, we propose to utilize multiple paths to spread traffic and deploy recent queue management schemes which can maximize network resource utilization and reduce both downtime and migration time for live migration techniques. In addition, a dynamic resource allocation scheme is presented to distribute workloads among geographically dispersed DCs considering their location based time varying costs due to e.g. carbon emission or bandwidth provision. For optimizing performance level objectives, we focus on interference among applications contending in shared resources and propose a novel VM consolidation scheme considering sensitivity of the VMs to their demanded resources. Further, to investigate the impact of uncertain parameters on cloud resource allocation and applications’ QoS such as unpredictable variations in demand, we develop an optimization model based on the theory of robust optimization. Furthermore, in order to handle the scalability issues in the context of large scale infrastructures, a robust and fast Tabu Search algorithm is designed and evaluated. / High availability, cost effectiveness and ease of application deployment have accelerated the adoption rate of cloud computing. This fast proliferation of cloud computing promotes the rapid development of large-scale infrastructures. However, large cloud datacenters (DCs) require infrastructure, design, deployment, scalability and reliability and need better management techniques to achieve sustainable design benefits. Resources inside cloud infrastructures often operate at low utilization, rarely exceeding 20-30%, which increases the operational cost significantly, especially due to energy consumption. To reduce operational cost without affecting quality of service (QoS) requirements, cloud applications should be allocated just enough resources to minimize their completion time or to maximize utilization.  The focus of this thesis is to enable resource-efficient and performance-aware cloud infrastructures by addressing above mentioned cost and performance related challenges. In particular, we propose algorithms, techniques, and deployment strategies for improving the dynamic allocation of virtual machines (VMs) into physical machines (PMs).

Avec l’évolution rapide des technologies réseaux et télécoms radios mobiles, les chercheurs sont actuellement en train de préparer l’arrivée d’une nouvelle génération baptisée 4G. Le réseau de 4ème génération qui est encore l’objet de travaux de recherche vise à améliorer l’efficacité spectrale et à augmenter la capacité de gestion du nombre des mobiles dans une même cellule. Il tend à offrir des débits élevés en situation de mobilité à grande ou faible vitesse. Il vise aussi à permettre et à faciliter l’interconnexion et l’interopérabilité entre différentes technologies existantes en rendant transparent à l’utilisateur le passage entre les réseaux. Enfin, il vise à éviter l’interruption des services durant le transfert intercellulaire, et à basculer l’utilisation vers le tout IP. Dans ce contexte, nous nous sommes intéressés en premier lieu aux problématiques de la QoS en situation de mobilité au sein d’une technologie candidate à la 4G (WiMAX mobile) pour du trafic temps-réel. Pour cela, nous avons comparé la performance de plusieurs protocoles de mobilité dans le contexte du Handover de niveau 2 et de niveau 3 et plus. Nous avons pour cela fait varier les modèles de mobilité, les configurations et les scénarios. Enfin, nous avons modélisé un algorithme décisionnel qui gère le Handover dans le WiMAX mobile en fonction de plusieurs paramètres d’entrées. Au travers de ces études, nous avons dégagé des protocoles de mobilité qui offrent un niveau de QoS acceptable pour un trafic temps-réel dans le cadre des scénarios envisagés. En deuxième lieu, nous nous sommes concentrés sur les problèmes d’interconnexion et d’interopérabilité entre les réseaux en tenant compte de la mobilité et du Handover vertical entre deux technologies. Pour cela, nous avons proposé de comparer des protocoles de mobilité puis de les combiner afin de diminuer les délais des trafics temps-réel au cours du Handover. Au niveau de l’interconnexion, nous avons proposé des modèles entre WiMAX mobile et de nombreux autres standards (802.11e, UMTS, DVB-S/RCS, LTE). Outre les solutions d’interconnexion, nous avons également mis en évidence la ou les combinaisons de protocoles de gestion de la mobilité qui permettent de garantir de la QoS. / With the rapid evolution of mobile radio telecommunications and networks technologies, researchers are currently preparing the arrival of a new generation called 4G. The 4th generation network aims to improve spectral efficiency and increase capacity to manage a large number of mobiles in a cell. It tries to provide high flow rates under high or low mobility. It also aims to enable and facilitate the interconnection and the interoperability between different technologies allowing transparent transition between networks. Finally, it aims to avoid interruption of services during the handover, and to switch an all-IP system. In this context, we are concerned first with QoS and mobility issues in Mobile WiMAX for the real-time traffic. We compared the performance of several mobility protocols in the context of the level 2 and level 3+ handovers. Several mobility models, configurations and scenarios were considered. Finally, we modeled a decision algorithm that manages the handover in mobile WiMAX based on several input parameters.Through these studies, we have identified mobility protocols that provide an acceptable QoS level for real-time traffic under the proposed scenarios. Secondly, we focused on the problems of interconnection and interoperability between networks, taking into account the mobility and vertical handovers between two technologies. For this, we proposed to compare mobility protocols or combine them to reduce delays for real-time traffic during the handover. We also proposed interconnection models between mobile WiMAX and many other standards (802.11e, UMTS, DVB-S/RCS, LTE). Besides interconnection solutions, we also highlighted the combination or combinations of management mobility protocols that can guarantee QoS.

The InfiniBand Architecture (IBA) network has been proposed as a new industrial standard with high-bandwidth and low-latency suitable for constructing high-performance interconnected cluster computing systems. This architecture replaces the traditional bus-based interconnection with a switch-based network for the server Input-Output (I/O) and inter-processor communications. The efficient Quality-of-Service (QoS) mechanism is fundamental to ensure the import at QoS metrics, such as maximum throughput and minimum latency, leaving aside other aspects like guarantee to reduce the delay, blocking probability, and mean queue length, etc. Performance modelling and analysis has been and continues to be of great theoretical and practical importance in the design and development of communication networks. This thesis aims to investigate efficient and cost-effective QoS mechanisms for performance analysis and improvement of InfiniBand networks in cluster-based computing systems. Firstly, a rate-based source-response link-by-link admission and congestion control function with improved Explicit Congestion Notification (ECN) packet marking scheme is developed. This function adopts the rate control to reduce congestion of multiple-class traffic. Secondly, a credit-based flow control scheme is presented to reduce the mean queue length, throughput and response time of the system. In order to evaluate the performance of this scheme, a new queueing network model is developed. Theoretical analysis and simulation experiments show that these two schemes are quite effective and suitable for InfiniBand networks. Finally, to obtain a thorough and deep understanding of the performance attributes of InfiniBand Architecture network, two efficient threshold function flow control mechanisms are proposed to enhance the QoS of InfiniBand networks; one is Entry Threshold that sets the threshold for each entry in the arbitration table, and other is Arrival Job Threshold that sets the threshold based on the number of jobs in each Virtual Lane. Furthermore, the principle of Maximum Entropy is adopted to analyse these two new mechanisms with the Generalized Exponential (GE)-Type distribution for modelling the inter-arrival times and service times of the input traffic. Extensive simulation experiments are conducted to validate the accuracy of the analytical models.

La croissance du réseau Internet, l'émergence de nouveaux besoins par l'avènement des terminaux dits intelligents (smartphones, tablettes tactiles, etc.) et l'apparition de nouvelles applications sous-jacentes induisent de nombreuses mutations dans l'usage de plus en plus massif des technologies de l'information dans notre vie quotidienne et dans tous les secteurs d'activités. Ces nouveaux usages ont nécessité de repenser le fondement même de l'architecture réseau qui a eu pour conséquence l'émergence de nouveaux concepts basés sur une vue "centrée sur l'usage" en lieu et place d'une vue "centrée sur le réseau". De fait, les mécanismes de contrôle du réseau de transport doivent non seulement exploiter les informations relatives aux plans de données, de contrôle et de gestion, mais aussi les connaissances, acquises ou apprises par inférence déductive ou inductive, sur l'état courant du réseau (trafic, ressources, rendu de l'application, etc.) de manière à accélérer la prise de décision par les éléments de contrôle du réseau. Les travaux faits dans le cadre de cette thèse concernent ce dernier aspect et rejoignent plus généralement ceux tournés sur les réseaux autonomiques. Il s'agit dans cette thèse de mettre en oeuvre des méthodes relatives à la gestion, à la distribution et à l'exploitation des connaissances nécessaires au bon fonctionnement du réseau de transport. Le plan de connaissances mis en oeuvre ici se base à la fois sur l'idée de développer une gestion au sein d'une structure hiérarchisée et adaptative où seuls certains noeuds sélectionnés sont en charge de la dissémination des connaissances et l'idée de relier ces noeuds au travers d'un ensemble de réseaux couvrants spécialisés permettant de faciliter l'exploitation de ces connaissances. Comparée aux plateformes traditionnellement utilisées, celle développée dans le cadre de cette thèse montre clairement l'intérêt des algorithmes élaborés au regard des temps d'accès, de distribution et de partage de charge entre les noeuds de contrôle pour la gestion des connaissances. A des fins de validation, cette plateforme a été utilisée dans deux exemples d'application: le Cloud computing et les smartgrids / The growth of the Internet, the emergence of new needs expressed by the advent of smart devices ( smartphones, touchpads , etc. ) and the development of new underlying applications induce many changes in the use of information technology in our everyday life and in all sectors. This new use that match new needs required to rethink the foundation of the network architecture itself, which has resulted in the emergence of new concepts based on a "use-centeric" view instead of a "network-centric" view. In fact, the control mechanisms of the transmission network must not only exploit the information on data, control and management planes, but also the knowledge acquired or learned by inductive or deductive inference on the current state of the network (traffic, resources, the rendering of the application, etc.) to accelerate decision making by the control elements of the network. This thesis is dealing with this latter aspect, which makes it consistent with work done on autonomic networks. It is about conceiving and implementing methods for the management, distribution and exploitation of knowledge necessary for the proper functioning of the transmission network. The knowledge plane that we implemented is based on both the idea of developing a management within an adaptive hierarchical structure where only some selected nodes are responsible for the dissemination of knowledge and the idea of linking these nodes through a spanning set of specialized networks to facilitate the exploitation of this knowledge. Compared to traditionally used platforms, the one developed in this thesis clearly shows the interest of the developed algorithms in terms of access time, distribution and load sharing between the control nodes for knowledge management. For validation purposes, our platform was tested on two application examples : Cloud computing and smart grids

Cette thèse a pour objectif de proposer de nouvelles approches d'ordonnancement, de coopération et de gestion de la mobilité dans les réseaux sans fil de type IEEE 802.11. Le maintien de la qualité de service (QoS), au niveau MAC, représente la caractéristique fondamentale de ces approches. L'analyse des mécanismes existants nous a conduits à retenir le protocole EDCF, supportant la QoS, comme une base de travail pour l'ensemble de nos propositions. Dans le but de pallier certaines faiblesses du standard 802.11, une nouvelle architecture à base de multi-ordonnanceurs HCF-T, est proposée. Les performances obtenues sont exprimées en termes de gestion du trafic, de maintien du débit, d'élimination de collisions et de réduction de la charge du réseau. Ensuite, un schéma coopératif est présenté et analysé. Il comporte une étude de deux protocoles de relayage AAF et DAF ainsi qu'une évaluation d'un ensemble de techniques de combinaison au niveau du récepteur. Concernant la problématique de la mobilité, nous avons retenu et analysé un scénario prenant en considération les différentes situations rencontrées dans un modèle réel. Un algorithme de résolution multi-couvertures est proposé afin de traiter l'accès dans les zones de recouvrement. Cette étude a mené à distinguer trois régimes de mobilité : faible, moyen et fort. Les performances sont évaluées en fonction des métriques MAC et pour chaque mode de mobilité, un schéma de synthèse est établi / This thesis proposes a new approach relating to the packets scheduling algorithm, the cooperation scheme and the nodes' mobility for IEEE 802.11 wireless network family. Considering the QoS delivery process at the MAC level consists the main feature of the proposal research study. The analysis of the current mechanisms leads to keep the protocol EDCF as the basic model for our work platform. In order to overcome the weakness of the earlier 802.11 standard, a new model based on multi-scheduler algorithm, called HCF-T, is proposed. The achieved performances are summarized following several criteria: traffic control, throughput improving, collisions avoidance, and network load decreasing. Furthermore, in the way of getting better results according to the PHY layer, we presented and analyzed a model of cooperative diversity scheme. It included a couple of relaying protocols AAF and DAF supported by a set of combining techniques to backup the signal at the receiver. To support node's mobility within EDCF, we built-up a model of WLAN which able to track node motion and control the access as in real condition. In the case of overlapping APs ranges, we developed a Multi-coverage algorithm aiming to carry out the session associations. As a result, three levels (Low, Medium, and High) of node's speed are discerned. Finally, EDCF has been implemented on various static and dynamic scenarios. The performances, based on the main MAC-layer metrics, such as throughput, End-2-End delay, and jitter, have been classified and comprehensively evaluated

The Internet of Things (IoT) has the vision to interconnect everything of the physical world and the virtual world. Advanced automated and adaptive connectivity of objects, systems, and services is expected to be achieved under the IoT context, especially in the industrial environment. Industry 4.0 with the goal of intelligent and self-adaptable manufacturing is driven by the IoT. The Object Layer, where real-time and reliable information acquisition from the physical objects carried out, is the basic enabler in the 3-layer industrial IoT system. Such acquisition system features deterministic access, reliable communication with failure resistance mechanism, latency-aware real-time response, deployable structure/protocol, and adaptive performance on various QoS demands. This thesis proposes a reliable RFID communication system for acquisition in the industrial environment. A discrete gateway structure and a contention-free communication protocol are designed to fulfill the unique system requirements. Such gateway structure offers a flexible configuration of readers and RF technologies. It enables a full duplex communication between the objects and the gateway. The designed MF-TDMA protocol can enhance the failure resistance and emergency report mechanism thanks to the separation of control link and data link in the gateway. Specifically, an optional ARQ mechanism, an independent/uniform synchronization and control method, and a slot allocation optimization algorithm are designed besides time-division and frequency-division multiplexing. Protocol implementations for different industrial situations illustrate the system ability for supporting the demands of various QoS. Finally, a 2.4-GHz/UWB hybrid positioning platform is explored based on the introduced RFID system. Taking advantage of the UWB technology, the positioning platform can achieve positioning accuracy from meter level to centimeter level. Hybrid tag prototype and specific communication process based on the MF-TDMA protocol are designed. An SDR UWB reader network, capable of evaluating multiple algorithms, is built to realize accurate positioning with an improved algorithm proposed. / <p>QC 20161109</p>

[pt] O desenvolvimento de ambientes femto-celulares traz um considerável aumento geral na capacidade de sistemas heterogêneos, porque a distância entre o transmissor e receptor é pequena em comparação ao clássico desenvolvimento macro-celular. Mas as aplicações e serviços que estão vindo, precisam de ainda mais capacidade. Na procura desse ganho na capacidade, se criam técnicas e procedimentos que trabalham principalmente na camada física e MAC. Entre elas temos o reuso de frequência unitário, o qual não se logra explodir toda a capacidade do sistema, por isso implementamos o reuso de frequência fracionário que encara diretamente os problemas de interferência co-layer (entre femto-estações) e cross-layer (entre macro e femto estações). Este reuso fracionário de frequência se da só a nível de femto-estações, deixando à macro-estação que utilize toda a banda de frequência atribuída para a macro-célula. Os claros resultados obtidos no nível do SINR, mostram as melhoras. Tomando como base a plataforma anterior de reuso fracionário, analisamos as estrategias de programação do recurso frente a uma aplicação de vídeo. As estrategias pesquisadas são classificadas em: aquelas que tomam em consideração a qualidade do canal e aquelas que além da qualidade do canal consideram dentro da sua métrica requerimentos QoS, em especial o retardo máximo. Estas ultimas são as mais adequadas quando se opera com aplicações de tempo real (vídeo conferência e VoIP). Para contemplar a faixa de funcionamento das melhoras obtidas, todos os cenários de simulação foram sometidos a três intensidades de trafego (leve, médio e pesado). Medidas feitas da vazão, retardo, perda de pacotes e níveis de justiça na repartição mostram os benefícios do efeito combinado do reuso fracionário como o algoritmo de programação utilizado. Com os resultados obtidos fazemos uma escolha do padrão de reuso mais adequado junto com o algoritmo que proporcionam o melhor rendimento, dependendo do cenário (familiares ou empresariais) e da aplicação a utilizar. / [en] The development of femtocells environments brings a considerable increase in the capacity of the heterogeneous systems, because the distance between the transmitter and the receptor is smaller than the classic macrocell development. But the applications and services that are coming need more capacity yet. Looking for that gain of capacity, has been created techniques and methods that work mainly in the physical and MAC layer. Among them, the unitary frequency reuse, that does not achieve to exploit all the system s capacity. Hence we have implemented the fractional frequency reuse that aim directly the problems of co-layer interference (Between femto base stations) and cross-layer interference (Between macro and femto base stations). This fractional reuse of frequency is only among femto-stations, leaving the macro-station that use all the frequency band given for the macro cell. The bright results obtained in the SINR level show the improvements. Based on previous platform of fractional reuse, we analyze the scheduling strategies of the resource with a video application. The studied strategies are classified in: those that consider the quality of the channel and those that beyond the quality of channel consider QoS requirements in its metric, specially the maximum delay time. The last are more adequate when operating with video applications in real time (Video conference, VoIP). To see the operating range of the obtained improvements, all the simulation scenarios were submitted to three intensities of traffic (light, medium and heavy). Measurements of throughput, delay, packet loss ratio and fair levels in the distribution show the benefits of the joint effects of the fractional reuse as the scheduling algorithm used. With the obtained results, we do a selection of the more adequate reuse pattern together with the algorithm that provides the best performance, depending of the scenario (home or business environment) and the applications to use.