312 research outputs found

    A hybrid network/host mobility management scheme for next generation networks

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    Includes bibliographical references.The author proposes a hybrid network/host interworking scheme to allow the MN to transition smoothly between different access networks supporting two distinct mobility approaches

    Techno-economic valuation of mobile communications scenarios

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    Valuation of large projects on new communications technologies is a challenging task. Major investments are required to spread out technology and services, the characteristics of which are still largely unknown. A balanced view is needed on capabilities of the technologies, market demand, and relevant value network actors and their economies. In this dissertation, comprehensive techno-economic modelling of these aspects will be introduced for valuation of selected business scenarios. The research framework is mobile data services and business architectures in the advent of new technologies, like UMTS (Universal Mobile Telecommunications System), WLAN (Wireless Local Area Network) and WiMAX (Worldwide Interoperability for Microwave Access). The techno-economic method in this context comprises the modelling of a large set of technology, market and other factors in relation to the business operations of the analysed market actors. The many uncertainties concerning future service innovations and market development set demands on scenario creation and parameter estimation. Traditional techno-economic investment project calculation is not enough. This study gives devices for strategic decision making by analysing three different technology transitions: The modelling of Western-European incumbent operator business starting from the early 2000's indicated that the UMTS deployment should be started without delay to maximise the long-term profits from the acquired licenses, contrary to looking for short-term investment payoffs that was prevalent after the telecommunications downturn. Results also show that the emerging WLAN technology would not become a substitute for UMTS, but the public WLAN will complement the UMTS based business architecture. Modelling of the upcoming mobile WiMAX in comparison to UMTS path indicated that the mobile WiMAX cannot challenge the UMTS, as the latter one offers a better business case for the key actors. In the last transition, techno-economic delta analysis was used to quantify the benefits from the fixed-mobile convergence. The main enhancements to the techno-economic method are first the extensive classification of advanced mobile services and related modelling of service diffusion, usage patterns, capacity requirements and revenues. The second contribution is to improve the analysis of service usage in relation to technology characteristics by integrating an end-user model that gives the demand and revenue potential of each service type, per user segment and utilised technology. A novelty is also the separation of network provisioning and service provisioning part of the business architecture into separate but interlinked models. The fourth contribution to the method is the application of real options method on large communications technology deployment projects, solving option modelling problems due to the complex dependencies of the project value on the investment timing. The introduced method starts from ordinary expected cash flow valuation, but adds to that the option value related to specific flexibility in the project

    NFV orchestration in edge and fog scenarios

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    Mención Internacional en el título de doctorLas infraestructuras de red actuales soportan una variedad diversa de servicios como video bajo demanda, video conferencias, redes sociales, sistemas de educación, o servicios de almacenamiento de fotografías. Gran parte de la población mundial ha comenzado a utilizar estos servicios, y los utilizan diariamente. Proveedores de Cloud y operadores de infraestructuras de red albergan el tráfico de red generado por estos servicios, y sus tareas de gestión no solo implican realizar el enrutamiento del tráfico, sino también el procesado del tráfico de servicios de red. Tradicionalmente, el procesado del tráfico ha sido realizado mediante aplicaciones/ programas desplegados en servidores que estaban dedicados en exclusiva a tareas concretas como la inspección de paquetes. Sin embargo, en los últimos anos los servicios de red se han virtualizado y esto ha dado lugar al paradigma de virtualización de funciones de red (Network Function Virtualization (NFV) siguiendo las siglas en ingles), en el que las funciones de red de un servicio se ejecutan en contenedores o máquinas virtuales desacopladas de la infraestructura hardware. Como resultado, el procesado de tráfico se ha ido haciendo más flexible gracias al laxo acople del software y hardware, y a la posibilidad de compartir funciones de red típicas, como firewalls, entre los distintos servicios de red. NFV facilita la automatización de operaciones de red, ya que tareas como el escalado, o la migración son típicamente llevadas a cabo mediante un conjunto de comandos previamente definidos por la tecnología de virtualización pertinente, bien mediante contenedores o máquinas virtuales. De todos modos, sigue siendo necesario decidir el en rutamiento y procesado del tráfico de cada servicio de red. En otras palabras, que servidores tienen que encargarse del procesado del tráfico, y que enlaces de la red tienen que utilizarse para que las peticiones de los usuarios lleguen a los servidores finales, es decir, el conocido como embedding problem. Bajo el paraguas del paradigma NFV, a este problema se le conoce en inglés como Virtual Network Embedding (VNE), y esta tesis utiliza el termino “NFV orchestration algorithm” para referirse a los algoritmos que resuelven este problema. El problema del VNE es NP-hard, lo cual significa que que es imposible encontrar una solución optima en un tiempo polinómico, independientemente del tamaño de la red. Como consecuencia, la comunidad investigadora y de telecomunicaciones utilizan heurísticos que encuentran soluciones de manera más rápida que productos para la resolución de problemas de optimización. Tradicionalmente, los “NFV orchestration algorithms” han intentado minimizar los costes de despliegue derivados de las soluciones asociadas. Por ejemplo, estos algoritmos intentan no consumir el ancho de banda de la red, y usar rutas cortas para no utilizar tantos recursos. Además, una tendencia reciente ha llevado a la comunidad investigadora a utilizar algoritmos que minimizan el consumo energético de los servicios desplegados, bien mediante la elección de dispositivos con un consumo energético más eficiente, o mediante el apagado de dispositivos de red en desuso. Típicamente, las restricciones de los problemas de VNE se han resumido en un conjunto de restricciones asociadas al uso de recursos y consumo energético, y las soluciones se diferenciaban por la función objetivo utilizada. Pero eso era antes de la 5a generación de redes móviles (5G) se considerase en el problema de VNE. Con la aparición del 5G, nuevos servicios de red y casos de uso entraron en escena. Los estándares hablaban de comunicaciones ultra rápidas y fiables (Ultra-Reliable and Low Latency Communications (URLLC) usando las siglas en inglés) con latencias por debajo de unos pocos milisegundos y fiabilidades del 99.999%, una banda ancha mejorada (enhanced Mobile Broadband (eMBB) usando las siglas en inglés) con notorios incrementos en el flujo de datos, e incluso la consideración de comunicaciones masivas entre maquinas (Massive Machine-Type Communications (mMTC) usando las siglas en inglés) entre dispositivos IoT. Es más, paradigmas como edge y fog computing se incorporaron a la tecnología 5G, e introducían la idea de tener dispositivos de computo más cercanos al usuario final. Como resultado, el problema del VNE tenía que incorporar los nuevos requisitos como restricciones a tener en cuenta, y toda solución debía satisfacer bajas latencias, alta fiabilidad, y mayores tasas de transmisión. Esta tesis estudia el problema des VNE, y propone algunos heurísticos que lidian con las restricciones asociadas a servicios 5G en escenarios edge y fog, es decir, las soluciones propuestas se encargan de asignar funciones virtuales de red a servidores, y deciden el enrutamiento del trafico en las infraestructuras 5G con dispositivos edge y fog. Para evaluar el rendimiento de las soluciones propuestas, esta tesis estudia en primer lugar la generación de grafos que representan redes 5G. Los mecanismos propuestos para la generación de grafos sirven para representar distintos escenarios 5G. En particular, escenarios de federación en los que varios dominios comparten recursos entre ellos. Los grafos generados también representan servidores en el edge, así como dispositivos fog con una batería limitada. Además, estos grafos tienen en cuenta los requisitos de estándares, y la demanda que se espera en las redes 5G. La generación de grafos propuesta sirve para representar escenarios federación en los que varios dominios comparten recursos entre ellos, y redes 5G con servidores edge, así como dispositivos fog estáticos o móviles con una batería limitada. Los grafos generados para infraestructuras 5G tienen en cuenta los requisitos de estándares, y la demanda de red que se espera en las redes 5G. Además, los grafos son diferentes en función de la densidad de población, y el área de estudio, es decir, si es una zona industrial, una autopista, o una zona urbana. Tras detallar la generación de grafos que representan redes 5G, esta tesis propone algoritmos de orquestación NFV para resolver con el problema del VNE. Primero, se centra en escenarios federados en los que los servicios de red se tienen que asignar no solo a la infraestructura de un dominio, sino a los recursos compartidos en la federación de dominios. Dos problemas diferentes han sido estudiados, uno es el problema del VNE propiamente dicho sobre una infraestructura federada, y el otro es la delegación de servicios de red. Es decir, si un servicio de red se debe desplegar localmente en un dominio, o en los recursos compartidos por la federación de dominios; a sabiendas de que el último caso supone el pago de cuotas por parte del dominio local a cambio del despliegue del servicio de red. En segundo lugar, esta tesis propone OKpi, un algoritmo de orquestación NFV para conseguir la calidad de servicio de las distintas slices de las redes 5G. Conceptualmente, el slicing consiste en partir la red de modo que cada servicio de red sea tratado de modo diferente dependiendo del trozo al que pertenezca. Por ejemplo, una slice de eHealth reservara los recursos de red necesarios para conseguir bajas latencias en servicios como operaciones quirúrgicas realizadas de manera remota. Cada trozo (slice) está destinado a unos servicios específicos con unos requisitos muy concretos, como alta fiabilidad, restricciones de localización, o latencias de un milisegundo. OKpi es un algoritmo de orquestación NFV que consigue satisfacer los requisitos de servicios de red en los distintos trozos, o slices de la red. Tras presentar OKpi, la tesis resuelve el problema del VNE en redes 5G con dispositivos fog estáticos y móviles. El algoritmo de orquestación NFV presentado tiene en cuenta las limitaciones de recursos de computo de los dispositivos fog, además de los problemas de falta de cobertura derivados de la movilidad de los dispositivos. Para concluir, esta tesis estudia el escalado de servicios vehiculares Vehicle-to-Network (V2N), que requieren de bajas latencias para servicios como la prevención de choques, avisos de posibles riesgos, y conducción remota. Para estos servicios, los atascos y congestiones en la carretera pueden causar el incumplimiento de los requisitos de latencia. Por tanto, es necesario anticiparse a esas circunstancias usando técnicas de series temporales que permiten saber el tráfico inminente en los siguientes minutos u horas, para así poder escalar el servicio V2N adecuadamente.Current network infrastructures handle a diverse range of network services such as video on demand services, video-conferences, social networks, educational systems, or photo storage services. These services have been embraced by a significant amount of the world population, and are used on a daily basis. Cloud providers and Network operators’ infrastructures accommodate the traffic rates that the aforementioned services generate, and their management tasks do not only involve the traffic steering, but also the processing of the network services’ traffic. Traditionally, the traffic processing has been assessed via applications/programs deployed on servers that were exclusively dedicated to a specific task as packet inspection. However, in recent years network services have stated to be virtualized and this has led to the Network Function Virtualization (Network Function Virtualization (NFV)) paradigm, in which the network functions of a service run on containers or virtual machines that are decoupled from the hardware infrastructure. As a result, the traffic processing has become more flexible because of the loose coupling between software and hardware, and the possibility of sharing common network functions, as firewalls, across multiple network services. NFV eases the automation of network operations, since scaling and migrations tasks are typically performed by a set of commands predefined by the virtualization technology, either containers or virtual machines. However, it is still necessary to decide the traffic steering and processing of every network service. In other words, which servers will hold the traffic processing, and which are the network links to be traversed so the users’ requests reach the final servers, i.e., the network embedding problem. Under the umbrella of NFV, this problem is known as Virtual Network Embedding (VNE), and this thesis refers as “NFV orchestration algorithms” to those algorithms solving such a problem. The VNE problem is a NP-hard, meaning that it is impossible to find optimal solutions in polynomial time, no matter the network size. As a consequence, the research and telecommunications community rely on heuristics that find solutions quicker than a commodity optimization solver. Traditionally, NFV orchestration algorithms have tried to minimize the deployment costs derived from their solutions. For example, they try to not exhaust the network bandwidth, and use short paths to use less network resources. Additionally, a recent tendency led the research community towards algorithms that minimize the energy consumption of the deployed services, either by selecting more energy efficient devices or by turning off those network devices that remained unused. VNE problem constraints were typically summarized in a set of resources/energy constraints, and the solutions differed on which objectives functions were aimed for. But that was before 5th generation of mobile networks (5G) were considered in the VNE problem. With the appearance of 5G, new network services and use cases started to emerge. The standards talked about Ultra Reliable Low Latency Communication (Ultra-Reliable and Low Latency Communications (URLLC)) with latencies below few milliseconds and 99.999% reliability, an enhanced mobile broadband (enhanced Mobile Broadband (eMBB)) with significant data rate increases, and even the consideration of massive machine-type communications (Massive Machine-Type Communications (mMTC)) among Internet of Things (IoT) devices. Moreover, paradigms such as edge and fog computing blended with the 5G technology to introduce the idea of having computing devices closer to the end users. As a result, the VNE problem had to incorporate the new requirements as constraints to be taken into account, and every solution should either satisfy low latencies, high reliability, or larger data rates. This thesis studies the VNE problem, and proposes some heuristics tackling the constraints related to 5G services in Edge and fog scenarios, that is, the proposed solutions assess the assignment of Virtual Network Functions to resources, and the traffic steering across 5G infrastructures that have Edge and Fog devices. To evaluate the performance of the proposed solutions, the thesis studies first the generation of graphs that represent 5G networks. The proposed mechanisms to generate graphs serve to represent diverse 5G scenarios. In particular federation scenarios in which several domains share resources among themselves. The generated graphs also represent edge servers, so as fog devices with limited battery capacity. Additionally, these graphs take into account the standard requirements, and the expected demand for 5G networks. Moreover, the graphs differ depending on the density of population, and the area of study, i.e., whether it is an industrial area, a highway, or an urban area. After detailing the generation of graphs representing the 5G networks, this thesis proposes several NFV orchestration algorithms to tackle the VNE problem. First, it focuses on federation scenarios in which network services should be assigned not only to a single domain infrastructure, but also to the shared resources of the federation of domains. Two different problems are studied, one being the VNE itself over a federated infrastructure, and the other the delegation of network services. That is, whether a network service should be deployed in a local domain, or in the pool of resources of the federation domain; knowing that the latter charges the local domain for hosting the network service. Second, the thesis proposes OKpi, a NFV orchestration algorithm to meet 5G network slices quality of service. Conceptually, network slicing consists in splitting the network so network services are treated differently based on the slice they belong to. For example, an eHealth network slice will allocate the network resources necessary to meet low latencies for network services such as remote surgery. Each network slice is devoted to specific services with very concrete requirements, as high reliability, location constraints, or 1ms latencies. OKpi is a NFV orchestration algorithm that meets the network service requirements among different slices. It is based on a multi-constrained shortest path heuristic, and its solutions satisfy latency, reliability, and location constraints. After presenting OKpi, the thesis tackles the VNE problem in 5G networks with static/moving fog devices. The presented NFV orchestration algorithm takes into account the limited computing resources of fog devices, as well as the out-of-coverage problems derived from the devices’ mobility. To conclude, this thesis studies the scaling of Vehicle-to-Network (V2N) services, which require low latencies for network services as collision avoidance, hazard warning, and remote driving. For these services, the presence of traffic jams, or high vehicular traffic congestion lead to the violation of latency requirements. Hence, it is necessary to anticipate to such circumstances by using time-series techniques that allow to derive the incoming vehicular traffic flow in the next minutes or hours, so as to scale the V2N service accordingly.The 5G Exchange (5GEx) project (2015-2018) was an EU-funded project (H2020-ICT-2014-2 grant agreement 671636). The 5G-TRANSFORMER project (2017-2019) is an EU-funded project (H2020-ICT-2016-2 grant agreement 761536). The 5G-CORAL project (2017-2019) is an EU-Taiwan project (H2020-ICT-2016-2 grant agreement 761586).Programa de Doctorado en Ingeniería Telemática por la Universidad Carlos III de MadridPresidente: Ioannis Stavrakakis.- Secretario: Pablo Serrano Yáñez-Mingot.- Vocal: Paul Horatiu Patra

    HARD HANDOVER OPTIMIZATION USING TIME WINDOW BASED HANDOVER ALGORITHM

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    ABSTRACT This paper shows and solves a handover problem occurring with current power control mechanisms in cochannel Wideband Code Division Multiple Access (WCDMA) heterogeneous networks. The problem is the mismatch between the required uplink transmits power when a user is communicating to a small cell and an underlying microcellular base-station. This paper introduces Time Window Handover (TWHO) algorithm to adapt the transmit power of the small cell users during the handover regime to prevent such Signal to Interference plus Noise Ratio (SINR) drops

    A Quality of Service framework for upstream traffic in LTE across an XG-PON backhaul

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    Passive Optical Networks (PON) are promising as a transport network technology due to the high network capacity, long reach and strong QoS support in the latest PON standards. Long Term Evolution (LTE) is a popular wireless technology for its large data rates in the last mile. The natural integration of LTE and XG-PON, which is one of the latest standards of PON, presents several challenges for XG-PON to satisfy the backhaul QoS requirements of aggregated upstream LTE applications. This thesis proves that a dedicated XG-PON-based backhaul is capable of ensuring the QoS treatment required by different upstream application types in LTE, by means of standard-compliant Dynamic Bandwidth Allocation (DBA) mechanisms. First the design and evaluation of a standard-compliant, robust and fast XG-PON simulation module developed for the state-of-the-art ns-3 network simulator is presented in the thesis. This XG-PON simulation module forms a trustworthy and large-scale simulation platform for the evaluations in the rest of the thesis, and has been released for use by the scientific community. The design and implementation details of the XGIANT DBA, which provides standard complaint QoS treatment in an isolated XG-PON network, are then presented in the thesis along with comparative evaluations with the recently-published EBU DBA. The evaluations explored the ability of both XGIANT and EBU in terms of queuing-delay and throughput assurances for different classes of simplified (deterministic) traffic models, for a range of upstream loading in XG-PON. The evaluation of XGIANT and EBU DBAs are then presented for the context of a dedicated XG-PON backhaul in LTE with regard to the influence of standard-compliant and QoS-aware DBAs on the performance of large-scale, UDP-based applications. These evaluations disqualify both XGIANT and EBU DBAs in providing prioritised queuing delay performances for three upstream application types (conversational voice, peer-to-peer video and best-effort Internet) in LTE; the evaluations also indicate the need to have more dynamic and efficient QoS policies, along with an improved fairness policy in a DBA used in the dedicated XG-PON backhaul to ensure the QoS requirements of the upstream LTE applications in the backhaul. Finally, the design and implementation details of two standard-compliant DBAs, namely Deficit XGIANT (XGIANT-D) and Proportional XGIANT (XGIANT-P), which provide the required QoS treatment in the dedicated XG-PON backhaul for all three application types in the LTE upstream are presented in the thesis. Evaluations of the XGIANT-D and XGIANT-P DBAs presented in the thesis prove the ability of the fine-tuned QoS and fairness policies in the DBAs in ensuring prioritised and fair queuing-delay and throughput efficiency for UDP- and TCP-based applications, generated and aggregated based on realistic conditions in the LTE upstream

    Mobile Offloading in Residential Wireless Access Markets

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    The growth of mobile data traffic has been increasing at a tremendous pace. Currently, mobile broadband is mostly served by macro base stations. Strong attenuation occurs when the signals penetrate through buildings affecting the quality of service. Hence, mobile operators need to enhance the capacity to minimise congestion problems and improve the coverage on their macro networks for better network operation. As most of the mobile traffic occurs indoors, there is a need for indoor network deployments. A qualitative analysis employing the combination of various research methods (value network configuration, system dynamics, expert interviews) has been carried out to investigate various factors besides mobile offloading, which could lead to a large-scale deployment of femtocells in homes with the focus on Finland. This study also discusses several options to cope with the mobile traffic growth and examines different indoor network deployment scenarios. Furthermore, the scenarios of Femtocell-as-a-Service are highlighted and its possible impacts on mobile operators’ business are covered as well. The analysis is also conducted to illustrate how different actors are interrelated in the home network business. The analysis reveals that the primary factor that will contribute to the success of femtocell deployment in homes is the need for future mobile offloading. However, many other factors have important implications which require careful consideration by mobile operators. With the presence of good macro network capacity like in Finland, new services and partnership with third party providers has been identified as the most important factor. Mobile operators need to offer an incentive to attract end-users to adopt a femtocell service due to the strong positioning of WiFi in homes. Therefore, new services would also enable the penetration of femtocells into homes to compete with WiFi access points. Three factors (interference mitigation and interoperability, femtocell management system, backhaul) are also important as these are needed to ensure the femtocell networks operate reliably. As lowering the cost is essential for building scale, the model of Femtocell-as-a-Service is useful as it reduces capital investments for mobile operators. Interviews with the experts found that major mobile operators are less likely to adopt this model. This is better suited for smaller mobile operators that want to quickly enter the femtocell business

    A Development Framework to Determine the Applicability of a Dry Port to Fremantle Port Supply Chains: a Case Study

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    Fremantle Ports’ landside container transport has environmental and social impacts and, through congestion, reduces the efficiency of its hinterland links. Incorporating dry ports into supply chains can reduce these impacts and increase seaport capacity and effective life. Using dry port characteristics, common criteria and development theory with a Fremantle Ports case study and user survey, a dry port development framework is established and validated. The framework demonstrates a dry port's role in Fremantle Ports operations
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