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Contribution to resource management in cellular access networks with limited backhaul capacityGaleana Zapién, Hiram 25 February 2011 (has links)
La interfaz radio de los sistemas de comunicaciones móviles es normalmente considerada como
la única limitación de capacidad en la red de acceso radio. Sin embargo, a medida que se van
desplegando nuevas y más eficientes interfaces radio, y de que el tráfico de datos y multimedia va
en aumento, existe la creciente preocupación de que la infraestructura de transporte (backhaul) de
la red celular pueda convertirse en el cuello de botella en algunos escenarios. En este contexto, la
tesis se centra en el desarrollo de técnicas de gestión de recursos que consideran de manera
conjunta la gestión de recursos en la interfaz radio y el backhaul. Esto conduce a un nuevo
paradigma donde los recursos del backhaul se consideran no sólo en la etapa de dimensionamiento,
sino que además son incluidos en la problemática de gestión de recursos.
Sobre esta base, el primer objetivo de la tesis consiste en evaluar los requerimientos de
capacidad en las redes de acceso radio que usan IP como tecnología de transporte, de acuerdo a las
recientes tendencias de la arquitectura de red. En particular, se analiza el impacto que tiene una
solución de transporte basada en IP sobre la capacidad de transporte necesaria para satisfacer los
requisitos de calidad de servicio en la red de acceso. La evaluación se realiza en el contexto de la
red de acceso radio de UMTS, donde se proporciona una caracterización detallada de la interfaz
Iub. El análisis de requerimientos de capacidad se lleva a cabo para dos diferentes escenarios:
canales dedicados y canales de alta velocidad. Posteriormente, con el objetivo de aprovechar
totalmente los recursos disponibles en el acceso radio y el backhaul, esta tesis propone un marco de
gestión conjunta de recursos donde la idea principal consiste en incorporar las métricas de la red de
transporte dentro del problema de gestión de recursos. A fin de evaluar los beneficios del marco de
gestión de recursos propuesto, esta tesis se centra en la evaluación del problema de asignación de
base, como estrategia para distribuir el tráfico entre las estaciones base en función de los niveles de
carga tanto en la interfaz radio como en el backhaul. Este problema se analiza inicialmente
considerando una red de acceso radio genérica, mediante la definición de un modelo analítico
basado en cadenas de Markov. Dicho modelo permite calcular la ganancia de capacidad que puede
alcanzar la estrategia de asignación de base propuesta. Posteriormente, el análisis de la estrategia
propuesta se extiende considerando tecnologías específicas de acceso radio. En particular, en el
contexto de redes WCDMA se desarrolla un algoritmo de asignación de base basado en simulatedannealing
cuyo objetivo es maximizar una función de utilidad que refleja el grado de satisfacción
de las asignaciones respecto los recursos radio y transporte. Finalmente, esta tesis aborda el diseño
y evaluación de un algoritmo de asignación de base para los futuros sistemas de banda ancha
basados en OFDMA. En este caso, el problema de asignación de base se modela como un problema
de optimización mediante el uso de un marco de funciones de utilidad y funciones de coste de
recursos. El problema planteado, que considera que existen restricciones de recursos tanto en la
interfaz radio como en el backhaul, es mapeado a un problema de optimización conocido como
Multiple-Choice Multidimensional Knapsack Problem (MMKP). Posteriormente, se desarrolla un
algoritmo de asignación de base heurístico, el cual es evaluado y comparado con esquemas de
asignación basados exclusivamente en criterios radio. El algoritmo concebido se basa en el uso de
los multiplicadores de Lagrange y está diseñado para aprovechar de manera simultánea el balanceo
de carga en la intefaz radio y el backhaul.
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Integrated Security by using MPLS-VPN for Retail-Banking Network : Case study Mehr bank, IranH.Daryani, Sara, Taslimi, Pouria January 2010 (has links)
<p>The studied application area is a private bank with different branches located in different provinces around the country. There was not integrated security solution to provide communication among different branches. Some of these branches could communicate through the satellite and the others could communicate through a different technology, such as asynchronous transfer mode (ATM).</p><p>Different bank security policies were applied and maintained for different branches separately. In addition, the number of branches is expected to grow during coming year in each province.</p><p>The old topology was partial mesh and it could not support enough redundancy in case of disruption. If a connection between two branches failed, other branches might lose their connectivity as well. In addition, it could not achieve optimum routing.</p><p>Providing integrated quality of service (QoS) for the wide area network (WAN) by using different technologies is not easy to achieve, and it causes so many problems for the system. The bank uses a variety of protocols for different applications, depending on its demand, so the new applied technology should not depend on protocols, or at least should support different protocols at a same time. In the old technology, the bank was responsible for granting availability and connectivity maintenance. Providing proper bandwidth is an important aspect in the bank scenario and for the old technology; supplying enough bandwidth was costly.</p><p>As mentioned above, the old applied technology was dependent upon different protocols. Therefore, packets in different open system interconnection layers (OSI layers) would have to check thoroughly to find the source/ destination address, data and so on, to reach the correct destination. This might cause security problems for entire system. In addition, processing packet in each layer of the OSI model is time consuming.</p><p>One important aspect for the retail-banking scenario is considering all features of the security domain, such as security policy, information security, physical security, access level control, integrated security for the system and so on. Some features of the security domain in this project were not covering completely, such as integrated information security, merged security policy, and integrated physical security for the system.</p><p>In this project, all mentioned problems are solved by implementing a specific communication technology which can overcome the problems above. This technology supports multiple protocols, and it provides fast and secure communication. It can also cover redundancy and it does not cost as much as previous technologies like ATM and satellite. Easy provisioning is one feature of this technology. In this technology, the service provider is responsible for granting availability and connectivity maintenance.</p><p>The mentioned features of the security domain, which were not covered by the old technology, will be covered by a proper, integrated security solution. The IP-based physical security systems provide centralized monitoring and they can define a merged security policy for all different branches around the country. Specific, pre-defined scenarios are created for different events in different situations.</p>
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Integrated Security by using MPLS-VPN for Retail-Banking Network : Case study Mehr bank, IranH.Daryani, Sara, Taslimi, Pouria January 2010 (has links)
The studied application area is a private bank with different branches located in different provinces around the country. There was not integrated security solution to provide communication among different branches. Some of these branches could communicate through the satellite and the others could communicate through a different technology, such as asynchronous transfer mode (ATM). Different bank security policies were applied and maintained for different branches separately. In addition, the number of branches is expected to grow during coming year in each province. The old topology was partial mesh and it could not support enough redundancy in case of disruption. If a connection between two branches failed, other branches might lose their connectivity as well. In addition, it could not achieve optimum routing. Providing integrated quality of service (QoS) for the wide area network (WAN) by using different technologies is not easy to achieve, and it causes so many problems for the system. The bank uses a variety of protocols for different applications, depending on its demand, so the new applied technology should not depend on protocols, or at least should support different protocols at a same time. In the old technology, the bank was responsible for granting availability and connectivity maintenance. Providing proper bandwidth is an important aspect in the bank scenario and for the old technology; supplying enough bandwidth was costly. As mentioned above, the old applied technology was dependent upon different protocols. Therefore, packets in different open system interconnection layers (OSI layers) would have to check thoroughly to find the source/ destination address, data and so on, to reach the correct destination. This might cause security problems for entire system. In addition, processing packet in each layer of the OSI model is time consuming. One important aspect for the retail-banking scenario is considering all features of the security domain, such as security policy, information security, physical security, access level control, integrated security for the system and so on. Some features of the security domain in this project were not covering completely, such as integrated information security, merged security policy, and integrated physical security for the system. In this project, all mentioned problems are solved by implementing a specific communication technology which can overcome the problems above. This technology supports multiple protocols, and it provides fast and secure communication. It can also cover redundancy and it does not cost as much as previous technologies like ATM and satellite. Easy provisioning is one feature of this technology. In this technology, the service provider is responsible for granting availability and connectivity maintenance. The mentioned features of the security domain, which were not covered by the old technology, will be covered by a proper, integrated security solution. The IP-based physical security systems provide centralized monitoring and they can define a merged security policy for all different branches around the country. Specific, pre-defined scenarios are created for different events in different situations.
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