Qualidade de serviço em redes IEEE 802.16 com topologia em malha

Mestrado em Engenharia Electrónica e TelecomunicaçõesO IEEE 802.16 apresenta-se actualmente como a tecnologia mais avançada e aliciante para o acesso de banda larga metropolitano. A sua topologia pontomultiponto (PMP) foi desenvolvida desde o início com suporte para qualidade de serviço (QoS) gerida pelo controlador ou operador da rede, podendo assim complementar, as actuais soluções móveis de terceira geração. Por outro lado, a topologia opcional “em malha” (Mesh) permite a criação de redes autoconfiguráveis e com encaminhamento de tráfego através de vários pontos da rede. No entanto, as especificações e mecanismos de QoS apresentados na norma não são consistentes para estes dois modos de operação. Com a presente dissertação pretende-se estudar e avaliar uma arquitectura de QoS para o modo Mesh, baseada nos mecanismos delineados para a topologia PMP, permitindo a coexistência dos dois modos de operação. A arquitectura apresentada foca-se numa gestão eficiente da largura de banda utilizando mensagens de controlo ao nível MAC introduzidas pelo standard IEEE 802.16. Os resultados obtidos mostram a eficiência das classes de serviço implementadas, convergindo com os requisitos de QoS do modo PMP. ABSTRACT: The IEEE 802.16 standard is by now the most advanced and attractive technology for the metropolitan broadband access. The point-to-multipoint (PMP) topology was developed from the beginning with quality of service (QoS) support, managed by the network operator, thus complementing the existing third-generation mobile solutions. On the other hand, the alternative Mesh topology allows the creation of self-configuring networks with traffic routing through various nodes. However, the QoS specifications and mechanisms presented in the standard are not consistent for these two operation modes. The present work aims to study and evaluate a QoS architecture for the Mesh mode, based on mechanisms designed to PMP and thus allowing the coexistence of the two operation modes. The proposed architecture focuses on an efficient network bandwidth management, using control messages at the MAC level as suggested in the IEEE 802.16 standard. The results show the efficiency of the implemented service classes, coming to a convergence with the quality requirements announced by PMP mode

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

End to end architecture and mechanisms for mobile and wireless communications in the Internet

Architecture et mécanismes de bout en bout pour les communications mobiles et sans fil dans l'Internet. La gestion performante de la mobilité et l'amélioration des performances des couches basses sont deux enjeux fondamentaux dans le contexte des réseaux sans fil. Cette thèse apporte des solutions originales et innovantes qui visent à répondre à ces deux problématiques empêchant à ce jour d'offrir des possibilités de communication performantes et sans couture aux usagers mobiles accédant à l'Internet via des réseaux d'accès locaux sans fil (WLAN). Ces solutions se distinguent en particulier par l'impact minimum qu'elles ont sur les protocoles standards de l'Internet (niveaux transport et réseau) ou de l'IEEE (niveaux physique et liaison de données). S'inscrivant dans les paradigmes de "bout en bout" et "cross-layer", notre architecture permet d'offrir des solutions efficaces pour la gestion de la mobilité : gestion de la localisation et des handover en particulier. En outre, nous montrons que notre approche permet également d'améliorer l'efficacité des transmissions ainsi que de résoudre efficacement plusieurs syndromes identifiés au sein de 802.11 tels que les anomalies de performance, l'iniquité entre les flux et l'absence de contrôle de débit entre la couche MAC et les couches supérieures. Cette thèse résout ces problèmes en combinant des modèles analytiques, des simulations et de réelles expérimentations. Ces mécanismes adaptatifs ont été développés et intégrés dans une architecture de communication qui fournit des services de communication à haute performance pour réseaux sans fils tels que WIFI et WIMAX. ABSTRACT : Wireless networks, because of the potential pervasive and mobile communication services they offer, are becoming the dominant Internet access networks. However, the legacy Internet protocols, still dominant at that time, have not been designed with mobility and wireless in mind. Therefore, numerous maladjustments and “defaults of impedance” can be observed when combining wireless physical and MAC layers with the traditional upper layers. This thesis proposes several solutions for a pacific coexistence between these communication layers that have been defined and designed independently. Reliable mobility management and Low layer performance enhancements are two main challenging issues in the context of wireless networks. Mobility management (which is mostly based on mobile IP architecture nowadays) aims to continuously assign and control the wireless connections of mobile nodes amongst a space of wireless access networks. Low layer performance enhancements mainly focus on the transmission efficiency such as higher rate, lower loss, interference avoidance. This thesis addresses these two important issues from an original and innovative approach that, conversely to the traditional contributions, entails a minimum impact on the legacy protocols and internet infrastructure. Following the “end to end” and “cross layer” paradigms, we address and offer efficient and light solutions to fast handover, location management and continuous connection support through a space of wireless networks. Moreover, we show that such an approach makes it possible to enhance transmission efficiency and solve efficiently several syndromes that plague the performances of current wireless networks such as performance anomaly, unfairness issues and maladjustment between MAC layer and upper layers. This thesis tackles these issues by combining analytical models, simulations and real experiments. The resulting mechanisms have been developed and integrated into adaptive mobility management communication architecture that delivers high performing communication services to mobile wireless systems, with a focus on WIFI and WIMAX access networks

An Introduction to Computer Networks

An open textbook for undergraduate and graduate courses on computer networks