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

Contribution to the improvement of the performance of wireless mesh networks providing real time services

Nowadays, people expectations for ubiquitous connectivity is continuously growing. Cities are now moving towards the smart city paradigm. Electricity companies aims to become part of smart grids. Internet is no longer exclusive for humans, we now assume the Internet of everything. We consider that Wireless Mesh Networks (WMNs) have a set of valuable features that will make it an important part of such environments. WMNs can also be use in less favored areas thanks to their low-cost deployment. This is socially relevant since it facilitates the digital divide reduction and could help to improve the population quality of life. Research and industry have been working these years in open or proprietary mesh solutions. Standardization efforts and real deployments establish a solid starting point.We expect that WMNs will be a supporting part for an unlimited number of new applications from a variety of fields: community networking, intelligent transportation systems, health systems, public safety, disaster management, advanced metering, etc. For all these cases, the growing needs of users for real-time and multimedia information is currently evident. On this basis, this thesis proposes a set of contributions to improve the performance of an application service of such type and to promote the better use of two critical resources (memory and energy) of WMNs.For the offered service, this work focuses on a Video on Demand (VoD) system. One of the requirements of this system is the high capacity support. This is mainly achieved by distributing the video contents among various distribution points which in turn consist of several video servers. Each client request that arrives to such video server cluster must be handled by a specific server in a way that the load is balanced. For such task, this thesis proposes a mechanism to appropriately select a specific video server such that the transfer time at the cluster could be minimized.On the other hand, mesh routers that creates the mesh backbone are equipped with multiple interfaces from different technologies and channel types. An important resource is the amount of memory intended for buffers. The quality of service perceived by the users are largely affected by the size of such buffers. This is because important network performance parameters such as packet loss probability, delay, and channel utilization are highly affected by the buffer sizes. An efficient use of memory for buffering, in addition to facilitate the mesh devices scalability, also prevents the problems associated with excessively large buffers. Most of the current works associate the buffer sizing problem with the dynamics of TCP congestion control mechanism. Since this work focuses on real time services, in which the use of TCP is unfeasible, this thesis proposes a dynamic buffer sizing mechanism mainly dedicated for such real time flows. The approach is based on the maximum entropy principle and allows that each device be able to dynamically self-configure its buffers to achieve more efficient memory utilization. The proper performance of the proposal has been extensively evaluated in wired and wireless interfaces. Classical infrastructure-based wireless and multi-hop mesh interfaces have been considered. Finally, when the WMN is built by the interconnection of user hand-helds, energy is a limited and scarce resource, and therefore any approach to optimize its use is valuable. For this case, this thesis proposes a topology control mechanism based on centrality metrics. The main idea is that, instead of having all the devices executing routing functionalities, just a subset of nodes are selected for this task. We evaluate different centralities, form both centralized and distributed perspectives. In addition to the common random mobility models we include the analysis of the proposal with a socially-aware mobility model that generates networks with a community structure.Actualmente las expectativas de las personas de una conectividad ubicua están creciendo. Las ciudades están trabajando para alcanzar el paradigma de ciudades inteligentes. Internet ha dejado de ser exclusivo de las personas y ahora se asume el Internet de todo. Las redes inalámbricas de malla (WMNs) poseen un valioso conjunto de características que las harán parte importante de tales entornos. Las WMNs pueden utilizarse en zonas menos favorecidas debido a su despliegue económico. Esto es socialmente relevante ya que facilita la reducción de la brecha digital y puede ayudar a mejorar la calidad de vida de la población. Los esfuerzos de estandarización y los despliegues de redes reales establecen un punto de partida sólido.Se espera entonces, que las WMNs den soporte a un número importante de nuevas aplicaciones y servicios, de una variedad de campos: redes comunitarias, sistemas de transporte inteligente, sistemas de salud y seguridad, operaciones de rescate y de emergencia, etc. En todos estos casos, es evidente la necesidad de disponer de información multimedia y en tiempo real. En base a estos precedentes, esta tesis propone un conjunto de contribuciones para mejorar el funcionamiento de un servicio de este tipo y promover un uso eficiente de dos recursos críticos (memoria y energía) de las WMNs.Para el servicio ofrecido, este trabajo se centra en un sistema de video bajo demanda. Uno de los requisitos de estos sistemas es el de soportar capacidades elevadas. Esto se consigue principalmente distribuyendo los contenidos de video entre diferentes puntos de distribución, los cuales a su vez están formados por varios servidores. Cada solicitud de un cliente que llega a dicho conjunto de servidores debe ser manejada por un servidor específico, de tal forma que la carga sea balanceada. Para esta tarea, esta tesis propone un mecanismo que selecciona apropiadamente un servidor de tal manera que el tiempo de transferencia del sistema sea minimizado.Por su parte, los enrutadores de malla que crean la red troncal están equipados con múltiples interfaces de diferentes tecnologías y tipos de canal. Un recurso muy importante para éstos es la memoria destinada a sus colas. La calidad de servicio percibida por los usuarios está altamente influenciada por el tamaño de las colas. Esto porque parámetros importantes del rendimiento de la red como la probabilidad de pérdida de paquetes, el retardo, y la utilización del canal se ven afectados por dicho tamaño. Un uso eficiente de tal memoria, a más de facilitar la escalabilidad de los equipos, también evita los problemas asociados a colas muy largas. La mayoría de los trabajos actuales asocian el problema de dimensionamiento de las colas con la dinámica del mecanismo de control de congestión de TCP. Debido a que este trabajo se enfoca en servicios en tiempo real, en los cuales no es factible usar TCP, esta tesis propone un mecanismo de dimensionamiento dinámico de colas dedicado principalmente a flujos en tiempo real. La propuesta está basada en el principio de máxima entropía y permite que los dispositivos sean capaces de auto-configurar sus colas y así lograr un uso más eficiente de la memoria. Finalmente, cuando la WMN se construye a través de la interconexión de los dispositivos portátiles, la energía es un recurso limitado y escaso, y cualquier propuesta para optimizar su uso es muy valorada. Para esto, esta tesis propone un mecanismo de control de topología basado en métricas de centralidad. La idea principal es que en lugar de que todos los dispositivos realicen funciones de enrutamiento, solo un subconjunto de nodos es seleccionado para esta tarea. Se evalúan diferentes métricas, desde una perspectiva centralizada y otra distribuida. A más de los modelos aleatorios clásicos de movilidad, se incluye el análisis de la propuesta con modelos de movilidad basados en información social que toman en cuenta el comportamiento humano y generan redes con una clara estructura de comunidade

Actas da 10ª Conferência sobre Redes de Computadores

Universidade do MinhoCCTCCentro AlgoritmiCisco SystemsIEEE Portugal Sectio