Low-Latency Upstream Scheduling in Multi-Tenant, SLA Compliant TWDM PON

We present a multi-tenant multi-wavelength upstream transmission scheme for virtualised PONs, enabling compliance with latency-oriented Service Level Agreements (SLAs). Our analysis highlights an important trade-off between single-channel vs. multi-channel PONs, depending on ONUs tuning time

View on 5G Architecture: Version 1.0

The current white paper focuses on the produced results after one year research mainly from 16 projects working on the abovementioned domains. During several months, representatives from these projects have worked together to identify the key findings of their projects and capture the commonalities and also the different approaches and trends. Also they have worked to determine the challenges that remain to be overcome so as to meet the 5G requirements. The goal of 5G Architecture Working Group is to use the results captured in this white paper to assist the participating projects achieve a common reference framework. The work of this working group will continue during the following year so as to capture the latest results to be produced by the projects and further elaborate this reference framework. The 5G networks will be built around people and things and will natively meet the requirements of three groups of use cases: • Massive broadband (xMBB) that delivers gigabytes of bandwidth on demand • Massive machine-type communication (mMTC) that connects billions of sensors and machines • Critical machine-type communication (uMTC) that allows immediate feedback with high reliability and enables for example remote control over robots and autonomous driving. The demand for mobile broadband will continue to increase in the next years, largely driven by the need to deliver ultra-high definition video. However, 5G networks will also be the platform enabling growth in many industries, ranging from the IT industry to the automotive, manufacturing industries entertainment, etc. 5G will enable new applications like for example autonomous driving, remote control of robots and tactile applications, but these also bring a lot of challenges to the network. Some of these are related to provide low latency in the order of few milliseconds and high reliability compared to fixed lines. But the biggest challenge for 5G networks will be that the services to cater for a diverse set of services and their requirements. To achieve this, the goal for 5G networks will be to improve the flexibility in the architecture. The white paper is organized as follows. In section 2 we discuss the key business and technical requirements that drive the evolution of 4G networks into the 5G. In section 3 we provide the key points of the overall 5G architecture where as in section 4 we elaborate on the functional architecture. Different issues related to the physical deployment in the access, metro and core networks of the 5G network are discussed in section 5 while in section 6 we present software network enablers that are expected to play a significant role in the future networks. Section 7 presents potential impacts on standardization and section 8 concludes the white paper

Optical Networks and Interconnects

The rapid evolution of communication technologies such as 5G and beyond, rely on optical networks to support the challenging and ambitious requirements that include both capacity and reliability. This chapter begins by giving an overview of the evolution of optical access networks, focusing on Passive Optical Networks (PONs). The development of the different PON standards and requirements aiming at longer reach, higher client count and delivered bandwidth are presented. PON virtualization is also introduced as the flexibility enabler. Triggered by the increase of bandwidth supported by access and aggregation network segments, core networks have also evolved, as presented in the second part of the chapter. Scaling the physical infrastructure requires high investment and hence, operators are considering alternatives to optimize the use of the existing capacity. This chapter introduces different planning problems such as Routing and Spectrum Assignment problems, placement problems for regenerators and wavelength converters, and how to offer resilience to different failures. An overview of control and management is also provided. Moreover, motivated by the increasing importance of data storage and data processing, this chapter also addresses different aspects of optical data center interconnects. Data centers have become critical infrastructure to operate any service. They are also forced to take advantage of optical technology in order to keep up with the growing capacity demand and power consumption. This chapter gives an overview of different optical data center network architectures as well as some expected directions to improve the resource utilization and increase the network capacity

Supporting Diverse Customers and Prioritized Traffic in Next-Generation Passive Optical Networks

The already high demand for more bandwidth usage has been growing rapidly. Access network traffic is usually bursty in nature and the present traffic trend is mostly video-dominant. This motivates the need for higher transmission rates in the system. At the same time, the deployment costs and maintenance expenditures have to be reasonable. Therefore, Passive Optical Networks (PON) are considered promising next-generation access technologies. As the existing PON standards are not suitable to support future-PON services and applications, the FSAN (Full Service Access Network) group and the ITU-T (Telecommunication Standardization Sector of the International Telecommunication Union) have worked on developing the NG- PON2 (Next Generation PON 2) standard. Resource allocation is a fundamental task in any PON and it is necessary to have an efficient scheme that reduces delay, maximizes bandwidth usage, and minimizes the resource wastage. A variety of DBA (Dynamic Bandwidth Allocation) and DWBA (Dynamic Wavelength and Bandwidth Allocation) algorithms have been proposed which are based on different PONs (e.g. EPON, GPON, XG-PON, 10G- EPON, etc.). But to our knowledge, no DWBA scheme for NG-PON2 system, with diverse customers and prioritized traffic, has been proposed yet. In this work, this problem is addressed and five different dynamic wavelength and bandwidth allocation (DWBA) schemes are proposed. First, mixed integer linear programming (MILP) models are developed to minimize the total delay of the high priority data. Due to the MILP’s high computational complexity, heuristic algorithms are developed based on the MILP model insights. The five heuristics algorithms are: No Block-Split Heuristic (NBH), Equal Block-Split Heuristic (EBH), Priority Based No Block-Split Heuristic (P-NBH), Priority Based Equal Block-Split Heuristic (P-EBH), and Priority Based Decider Block-Split Heuristic (P-DBH). Six priority classes of requests are introduced with the goal of minimizing the total delay for the high priority data and to lessen the bandwidth wastage of the system. Finally, experiments for the performance evaluation of the five DWBA schemes are conducted. The results show that P-NBH, P-EBH, P-DBH schemes show a 47.63% less delay and 30% of less bandwidth wastage on average for the highest priority data transmission than the schemes without priority support (NBH and EBH). Among these five schemes, NBH method has the highest delay, whereas EBH and P-EBH waste more bandwidth than the other schemes. P-DBH is the most efficient among the five because this scheme offers the lowest delay for high priority data and the minimum bandwidth wastage for lower priority ones. Adviser: Byrav Ramamurth

Enhanced connectivity in wireless mobile programmable networks

Mención Interancional en el título de doctorThe architecture of current operator infrastructures is being challenged by the non-stop growing demand of data hungry services appearing every day. While currently deployed operator networks have been able to cope with traffic demands so far, the architectures for the 5th generation of mobile networks (5G) are expected to support unprecedented traffic loads while decreasing costs associated with the network deployment and operations. Indeed, the forthcoming set of 5G standards will bring programmability and flexibility to levels never seen before. This has required introducing changes in the architecture of mobile networks, enabling different features such as the split of control and data planes, as required to support rapid programming of heterogeneous data planes. Network softwarisation is hence seen as a key enabler to cope with such network evolution, as it permits controlling all networking functions through (re)programming, thus providing higher flexibility to meet heterogeneous requirements while keeping deployment and operational costs low. A great diversity in terms of traffic patterns, multi-tenancy, heterogeneous and stringent traffic requirements is therefore expected in 5G networks. Software Defined Networking (SDN) and Network Function Virtualisation (NFV) have emerged as a basic tool-set for operators to manage their infrastructure with increased flexibility and reduced costs. As a result, new 5G services can now be envisioned and quickly programmed and provisioned in response to user and market necessities, imposing a paradigm shift in the services design. However, such flexibility requires the 5G transport network to undergo a profound transformation, evolving from a static connectivity substrate into a service-oriented infrastructure capable of accommodating the various 5G services, including Ultra-Reliable and Low Latency Communications (URLLC). Moreover, to achieve the desired flexibility and cost reduction, one promising approach is to leverage virtualisation technologies to dynamically host contents, services, and applications closer to the users so as to offload the core network and reduce the communication delay. This thesis tackles the above challengeswhicharedetailedinthefollowing. A common characteristic of the 5G servicesistheubiquityandthealmostpermanent connection that is required from the mobile network. This really imposes a challenge in thesignallingproceduresprovidedtogettrack of the users and to guarantee session continuity. The mobility management mechanisms will hence play a central role in the 5G networks because of the always-on connectivity demand. Distributed Mobility Management (DMM) helps going towards this direction, by flattening the network, hence improving its scalability,andenablinglocalaccesstotheInternet and other communication services, like mobile-edge clouds. Simultaneously, SDN opens up the possibility of running a multitude of intelligent and advanced applications for network optimisation purposes in a centralised network controller. The combination of DMM architectural principles with SDN management appears as a powerful tool for operators to cope with the management and data burden expected in 5G networks. To meet the future mobile user demand at a reduced cost, operators are also looking at solutions such as C-RAN and different functional splits to decrease the cost of deploying and maintaining cell sites. The increasing stress on mobile radio access performance in a context of declining revenues for operators is hence requiring the evolution of backhaul and fronthaul transport networks, which currently work decoupled. The heterogeneity of the nodes and transmisión technologies inter-connecting the fronthaul and backhaul segments makes the network quite complex, costly and inefficient to manage flexibly and dynamically. Indeed, the use of heterogeneous technologies forces operators to manage two physically separated networks, one for backhaul and one forfronthaul. In order to meet 5G requirements in a costeffective manner, a unified 5G transport network that unifies the data, control, and management planes is hence required. Such an integrated fronthaul/backhaul transport network, denoted as crosshaul, will hence carry both fronthaul and backhaul traffic operating over heterogeneous data plane technologies, which are software-controlled so as to adapt to the fluctuating capacity demand of the 5G air interfaces. Moreover, 5G transport networks will need to accommodate a wide spectrum of services on top of the same physical infrastructure. To that end, network slicing is seen as a suitable candidate for providing the necessary Quality of Service (QoS). Traffic differentiation is usually enforced at the border of the network in order to ensure a proper forwarding of the traffic according to its class through the backbone. With network slicing, the traffic may now traverse many slice edges where the traffic policy needs to be enforced, discriminated and ensured, according to the service and tenants needs. However, the very basic nature that makes this efficient management and operation possible in a flexible way – the logical centralisation – poses important challenges due to the lack of proper monitoring tools, suited for SDN-based architectures. In order to take timely and right decisions while operating a network, centralised intelligence applications need to be fed with a continuous stream of up-to-date network statistics. However, this is not feasible with current SDN solutions due to scalability and accuracy issues. Therefore, an adaptive telemetry system is required so as to support the diversity of 5G services and their stringent traffic requirements. The path towards 5G wireless networks alsopresentsacleartrendofcarryingoutcomputations close to end users. Indeed, pushing contents, applications, and network functios closer to end users is necessary to cope with thehugedatavolumeandlowlatencyrequired in future 5G networks. Edge and fog frameworks have emerged recently to address this challenge. Whilst the edge framework was more infrastructure-focused and more mobile operator-oriented, the fog was more pervasive and included any node (stationary or mobile), including terminal devices. By further utilising pervasive computational resources in proximity to users, edge and fog can be merged to construct a computing platform, which can also be used as a common stage for multiple radio access technologies (RATs) to share their information, hence opening a new dimension of multi-RAT integration.La arquitectura de las infraestructuras actuales de los operadores está siendo desafiada por la demanda creciente e incesante de servicios con un elevado consumo de datos que aparecen todos los días. Mientras que las redes de operadores implementadas actualmente han sido capaces de lidiar con las demandas de tráfico hasta ahora, se espera que las arquitecturas de la quinta generación de redes móviles (5G) soporten cargas de tráfico sin precedentes a la vez que disminuyen los costes asociados a la implementación y operaciones de la red. De hecho, el próximo conjunto de estándares 5G traerá la programabilidad y flexibilidad a niveles nunca antes vistos. Esto ha requerido la introducción de cambios en la arquitectura de las redes móviles, lo que permite diferentes funciones, como la división de los planos de control y de datos, según sea necesario para soportar una programación rápida de planos de datos heterogéneos. La softwarisación de red se considera una herramienta clave para hacer frente a dicha evolución de red, ya que proporciona la capacidad de controlar todas las funciones de red mediante (re)programación, proporcionando así una mayor flexibilidad para cumplir requisitos heterogéneos mientras se mantienen bajos los costes operativos y de implementación. Por lo tanto, se espera una gran diversidad en términos de patrones de tráfico, multi-tenancy, requisitos de tráfico heterogéneos y estrictos en las redes 5G. Software Defined Networking (SDN) y Network Function Virtualisation (NFV) se han convertido en un conjunto de herramientas básicas para que los operadores administren su infraestructura con mayor flexibilidad y menores costes. Como resultado, los nuevos servicios 5G ahora pueden planificarse, programarse y aprovisionarse rápidamente en respuesta a las necesidades de los usuarios y del mercado, imponiendo un cambio de paradigma en el diseño de los servicios. Sin embargo, dicha flexibilidad requiere que la red de transporte 5G experimente una transformación profunda, que evoluciona de un sustrato de conectividad estática a una infraestructura orientada a servicios capaz de acomodar los diversos servicios 5G, incluso Ultra-Reliable and Low Latency Communications (URLLC). Además, para lograr la flexibilidad y la reducción de costes deseadas, un enfoque prometedores aprovechar las tecnologías de virtualización para alojar dinámicamente los contenidos, servicios y aplicaciones más cerca de los usuarios para descargar la red central y reducir la latencia. Esta tesis aborda los desafíos anteriores que se detallan a continuación. Una característica común de los servicios 5G es la ubicuidad y la conexión casi permanente que se requiere para la red móvil. Esto impone un desafío en los procedimientos de señalización proporcionados para hacer un seguimiento de los usuarios y garantizar la continuidad de la sesión. Por lo tanto, los mecanismos de gestión de la movilidad desempeñarán un papel central en las redes 5G debido a la demanda de conectividad siempre activa. Distributed Mobility Management (DMM) ayuda a ir en esta dirección, al aplanar la red, lo que mejora su escalabilidad y permite el acceso local a Internet y a otros servicios de comunicaciones, como recursos en “nubes” situadas en el borde de la red móvil. Al mismo tiempo, SDN abre la posibilidad de ejecutar una multitud de aplicaciones inteligentes y avanzadas para optimizar la red en un controlador de red centralizado. La combinación de los principios arquitectónicos DMM con SDN aparece como una poderosa herramienta para que los operadores puedan hacer frente a la carga de administración y datos que se espera en las redes 5G. Para satisfacer la demanda futura de usuarios móviles a un coste reducido, los operadores también están buscando soluciones tales como C-RAN y diferentes divisiones funcionales para disminuir el coste de implementación y mantenimiento de emplazamientos celulares. El creciente estrés en el rendimiento del acceso a la radio móvil en un contexto de menores ingresos para los operadores requiere, por lo tanto, la evolución de las redes de transporte de backhaul y fronthaul, que actualmente funcionan disociadas. La heterogeneidad de los nodos y las tecnologías de transmisión que interconectan los segmentos de fronthaul y backhaul hacen que la red sea bastante compleja, costosa e ineficiente para gestionar de manera flexible y dinámica. De hecho, el uso de tecnologías heterogéneas obliga a los operadores a gestionar dos redes separadas físicamente, una para la red de backhaul y otra para el fronthaul. Para cumplir con los requisitos de 5G de manera rentable, se requiere una red de transporte única 5G que unifique los planos de control, datos y de gestión. Dicha red de transporte fronthaul/backhaul integrada, denominada “crosshaul”, transportará tráfico de fronthaul y backhaul operando sobre tecnologías heterogéneas de plano de datos, que están controladas por software para adaptarse a la demanda de capacidad fluctuante de las interfaces radio 5G. Además, las redes de transporte 5G necesitarán acomodar un amplio espectro de servicios sobre la misma infraestructura física y el network slicing se considera un candidato adecuado para proporcionar la calidad de servicio necesario. La diferenciación del tráfico generalmente se aplica en el borde de la red para garantizar un reenvío adecuado del tráfico según su clase a través de la red troncal. Con el networkslicing, el tráfico ahora puede atravesar muchos fronteras entre “network slices” donde la política de tráfico debe aplicarse, discriminarse y garantizarse, de acuerdo con las necesidades del servicio y de los usuarios. Sin embargo, el principio básico que hace posible esta gestión y operación eficientes de forma flexible – la centralización lógica – plantea importantes desafíos debido a la falta de herramientas de supervisión necesarias para las arquitecturas basadas en SDN. Para tomar decisiones oportunas y correctas mientras se opera una red, las aplicaciones de inteligencia centralizada necesitan alimentarse con un flujo continuo de estadísticas de red actualizadas. Sin embargo, esto no es factible con las soluciones SDN actuales debido a problemas de escalabilidad y falta de precisión. Por lo tanto, se requiere un sistema de telemetría adaptable para respaldar la diversidad de los servicios 5G y sus estrictos requisitos de tráfico. El camino hacia las redes inalámbricas 5G también presenta una tendencia clara de realizar acciones cerca de los usuarios finales. De hecho, acercar los contenidos, las aplicaciones y las funciones de red a los usuarios finales es necesario para hacer frente al enorme volumen de datos y la baja latencia requerida en las futuras redes 5G. Los paradigmas de “edge” y “fog” han surgido recientemente para abordar este desafío. Mientras que el edge está más centrado en la infraestructura y más orientado al operador móvil, el fog es más ubicuo e incluye cualquier nodo (fijo o móvil), incluidos los dispositivos finales. Al utilizar recursos de computación de propósito general en las proximidades de los usuarios, el edge y el fog pueden combinarse para construir una plataforma de computación, que también se puede utilizar para compartir información entre múltiples tecnologías de acceso radio (RAT) y, por lo tanto, abre una nueva dimensión de la integración multi-RAT.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Carla Fabiana Chiasserini.- Secretario: Vincenzo Mancuso.- Vocal: Diego Rafael López Garcí

Networks for Future Services in a Smart City:Lessons Learned from the Connected OFCity Challenge 2017

The drive toward ubiquitous communications has long been encompassed by the concept of a connected or smart city. The idea that data transfer and real-time data analysis can enhance the quality of life for urban inhabitants is compelling, and one can easily envision the provision of exciting new services and applications that such an information-driven city could provide. The challenge in achieving a truly smart city stems largely from communications technologies-fixed line, wireless, backhaul, and fronthaul-and how these are combined to provide fast, reliable, and secure communications coverage. Here, we report on the key observations from the Connected OFCity Challenge competition, held at OFC 2017, which addressed the fixed and wireless access network requirements for smart cities. It is shown that from a technological perspective, future optical networks will be capable of securely supporting extremely low-latency and high-bandwidth applications. However, as shown by using Networked Music Performance as a particularly challenging example application, how readily this is achieved will depend on the interplay between wired and wireless access services. © 1979-2012 IEEE

Mecanismos para gerenciamento de banda passante em redes ópticas passivas Ethernet com clientes locatários de múltiplas unidades ópticas de redes

Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As atuais redes de acesso banda larga à Internet necessitam dar suporte às altas demandas de diversas aplicações tais como voz sobre IP (VoIP), streaming de vídeo UHD, videoconferência, internet das coisas (IoT) e jogos interativos. A tecnologia de redes ópticas passivas (PONs) é considerada promissora para fornecer alta capacidade de acesso com um custo-benefício aceitável. Existem duas diferentes tecnologias que disputam o mercado das redes ópticas; Ethernet PON (EPON) e Gigabit Capable PON(GPON). Devido ao alto custo de aquisição e manutenção de uma infraestrutura PON, muitas empresas (clientes) recorrem a fornecedores de infraestrutura (InP) para reduzir os altos custo, por meio do aluguel de uma porção dos recursos da PON. Esses clientes podem ser, por exemplo, operadores de rede móvel ou provedores de serviços virtuais, que podem adquirir múltiplas unidades da rede óptica (ONU) conectadas em uma única PON. Essa facilidade de alugar múltiplas ONUs pode gerar problemas de balanceamento de carga entre ONUs, uma vez que os atuais algoritmos de alocação de banda passante (DBA) são capazes de garantir banda para uma única ONU. Consequentemente, picos de demanda de banda passante podem ultrapassar a banda garantida em algumas ONUs e, ao mesmo tempo, subutilizar a banda garantida em outras ONUs de um mesmo cliente. Nesta dissertação, aborda-se o problema de gerenciamento de largura de banda para clientes multi-ONU nas redes EPON. Propõe-se um algoritmo de alocação dinâmica de banda passante (DBA) (MOS-IPACT) para dar suporte ao contrato de serviço (SLA) para clientes com várias ONUs. O mecanismo proposto distribui a largura de banda agregada entre ONUs de um mesmo cliente, com o objetivo de melhorar a utilização da largura de banda. Além disso propõe-se um algoritmo DBA para EPONs (subMOSIPACT) com o objetivo de garantir banda passante em diferentes níveis de granularidade. Este algoritmo é fundamental para clientes multi-ONU e que oferecem diversos tipos de serviços. Por exemplo, um operador da rede virtual pode alugar as ONUs de um InP para oferecer serviços corporativos e residenciais. Introduz-se, também, um algoritmo DBA para EPONs (coopMOS-IPACT) que permite a cooperação entre clientes. O algoritmo proposto permite que clientes cooperativos compartilhem banda passante não utilizada a fim de aumentar a banda disponível para alocação mas sem afetar seus SLAs individuais. Os resultados mostram que os três algoritmos propostos são capazes de garantir banda passante para clientes multi-ONU, mesmo em condições de tráfego desbalanceadas; Além de garantir banda passante em diferentes níveis de granularidade aumentando o suporte aos requisitos de qualidade de serviço (QoS). Resultados derivados por simulação mostraram que os algoritmos distribuem eficientemente a largura de banda entre os clientes multi-ONU bem como para clientes convencionais que possuem uma única ONU. Por fim, este trabalho mostra os benefícios do modelo de clientes cooperativos para aumentar a largura de banda disponívelAbstract: Current broadband access networks need to support the Quality of Service (QoS) requirements of diverse application such as voice over IP (VoIP), ultra-high video streaming, video conferencing, Internet of Things (IoT) and interactive gaming. Passive Optical Networks (PONs) is considered a promising solution to provides high access capacity with acceptable cost-benefit. Two different technologies share the optical access networks market: Ethernet PON (EPON) and Gigabit Capable PON (GPON). However, the deployment of PON infrastructure involves significant costs. On the other hand, Infrastructure Provider (InP) can alleviate these costs by leasing their PONs to several enterprises (customers). These customers can be Mobile Network Operators (MNOs), multi-site enterprises, or virtual service providers. New scenarios are envisioned in which customers owning multiple Optical Network Units (ONUs) (multi-ONUs customers) are connected to a single PON. However, current EPON Dynamic Bandwidth Allocation (DBA) algorithms are able to support only guaranteed bandwidth for individual ONUs. Consequently, peaks of bandwidth demand may surpass the guaranteed bandwidth for some ONUs and, at the same time, underutilize the bandwidth in other ONUs of a multi-ONU customer. In this work, the bandwidth management problem for multi-ONU customers in EPON network is addressed. This dissertation proposes a mechanisms for the support of multiONU Service Level Agreements (SLA) in DBA algorithms for EPONs. The proposed DBA algorithms (MOS-IPACT) allows customers owning multiple ONUs to redistribute the aggregated bandwidth of the group of ONUs to better balance the bandwidth utilization. This dissertation also proposes a DBA algorithm for EPON networks (subMOS-IPACT) with the objective of assuring bandwidth at different levels of granularity. This algorithm is quite important for multi-ONU customers offering diverse type of services. For example, a virtual network operator can lease ONUs from an InP to offer enterprise and residential services to its client.This work also introduce a DBA algorithm for EPONs (coopMOS-IPACT), which allows cooperation between customers. The proposed DBA algorithm allows cooperative customers share the unused bandwidth without affecting their individual multi-ONU SLAs. Results show that the three proposed Dynamic Bandwidth Allocation (DBA) algorithms are able to guarantee bandwidth for multi-Optical Network Unit (ONU) customers even in unbalancing traffic conditions. Furthermore, assuring bandwidth at different levels of granularity improves the Quality of Service (QoS) providing. Simulation results showed that the mechanisms efficiently distributes bandwidth between multi-ONU customers and traditional customers owning a single ONU. Finally, this work show the benefits of cooperative customers model in order to increase the available bandwidthMestradoCiência da ComputaçãoMestre em Ciência da Computação132308/2016-9CNP

Network slicing architecture for SDM and analog-radio-over-fiber-based 5G fronthaul networks

\u3cp\u3eThe blueSPACE project focuses on the study of innovative technologies to overcome the limitations of current fronthaul networks. The key technology proposed is space-division multiplexing, which makes it possible to increase the capacity available in conventional single-mode fibers, effectively encompassing this capacity to the forecasted bandwidth demands imposed by 5G mobile communications. In this paper, we present the innovative optical fronthaul infrastructure proposed in the project and the tailored extensions to the European Telecommunications Standards Institute network function virtualization management and orchestration architecture for this enhanced infrastructure together with practical implementation considerations.\u3c/p\u3

Contributing to the pathway towards 5G experimentation with an SDN-controlled network box

Καθώς η απαίτηση σε ευρυζωνικές υπηρεσίες κινητών επικοινωνιών αυξάνεται ραγδαία, τα υπάρχοντα δίκτυα κινητών επικοινωνιών πλησιάζουν τα όριά τους κάνοντας επιτακτική την ανάγκη εξέλιξής τους η οποία θα επέλθει με την τεχνολογική άφιξη της επόμενης γενιάς κινητών επικοινωνιών, ευρέως γνωστής ως 5G. Το 5G μεταφέρει όλες εκείνες τις δυνατότητες οι οποίες είναι απαραίτητες για να καλυφθούν οι συνεχώς αυξανόμενες ανάγκες σε ευρυζωνικές υπηρεσίες, να υποστηρίξουν το Internet of Things καθώς και να ενοποιήσουν ετερογενείς υπηρεσίες σε διαφορετικές βιομηχανίες. Η παρούσα διπλωματική εργασία στοχεύει να παρουσιάσει το “Network in a box”, ένα καινοτόμο εργαλείο που αναπτύξαμε στο εργαστήριο, το οποίο βασίζεται επάνω στους θεμέλιους λίθους του 5G, το SDN και το NFV. Με το SDN να είναι η νέα προσέγγιση στα δίκτυα κινητών επικοινωνιών, ο έλεγχος διαχωρίζεται από τα δεδομένα παρέχοντας τη δυνατότητα οποιεσδήποτε αποφάσεις ελέγχου, να λαμβάνονται κεντρικά, μετατρέποντας έτσι τις κλασικές δικτυακές συσκευές σε απλά προωθητικά στοιχεία του δικτύου. Η συγκεκριμένη διάταξη μιμείται ένα πραγματικό δίκτυο, το οποίο διαθέτει δυνατότητες αυτο-οργάνωσης και αυτο-βελτίωσης, προσομοιώνοντας τη λειτουργία του 5G δικτύου. Το συγκεκριμένο εργαλείο είναι επίσης ικανό να παράσχει KPI μετρικές του 5G δικτύου κάτω από πραγματικές συνθήκες ενόσω αληθινές δικτυακές συσκευές είναι συνδεδεμένες σε αυτό. Η δομή της παρούσας διπλωματικής εργασίας αναλύεται σε πέντε κεφάλαια. Το πρώτο κεφάλαιο παρουσιάζει τις προκλήσεις που σύντομα θα κληθούν να αντιμετωπίσουν τα δίκτυα κινητών επικοινωνιών και πώς αυτές μπορούν να καλυφθούν με την τεχνολογία του 5G. Το δεύτερο κεφάλαιο εισάγει την τάση στην αγορά των κινητών επικοινωνιών που διαφένεται πίσω από την επερχόμενη άφιξη του 5G, αποκαλύπτοντας το επιχειρηματικό πλαίσιο για επιχειρήσεις, καταναλωτές και συνεργασίες όπως επίσης και κάποιες περιπτώσεις χρήσης που αντικατοπτρίζουν την διαρκή εξέλιξη στις ευρυζωνικές υπηρεσίες κινητών επικοινωνιών. Το τρίτο κεφάλαιο εμπεριέχει μια μικρή επισκόπηση των τρέχοντων έργων πάνω στο 5G, τα οποία ξεκίνησαν υπό την αιγίδα της Ευρωπαϊκής Επιτροπής με τη συνεργασία προμηθευτών τεχνολογίας επικοινωνιών, παρόχων υπηρεσιών, μικρομεσαίων επιχειρήσεων και πανεπιστημίων. Γίνεται επίσης αναφορά στις βασικές τεχνολογίες του 5G και στις δραστηριότητες προτυποποίησής του. Προχωρώντας στο τέταρτο κεφάλαιο, περιγράφουμε σε βάθος την αρχιτεκτονική του 5G δικτύου, αναλύοντας τα SDN, NFV, MANO και εξετάζουμε πώς αυτά συνεισφέρουν στη βιωσιμότητα του δικτύου. Τέλος, στο πέμπτο κεφάλαιο εισάγουμε μια καινοτόμο ιδέα που αναπτύξαμε στο εργαστήριο δικτύων του πανεπιστημίου μας, ένα πλήρως αυτόνομο δικτυακό εργαλείο, το “Network in a box”. Παρουσιάζουμε σε βάθος πώς αυτός ο server μπορεί να εγκατασταθεί και να λειτουργήσει καθώς και τις δυνατότητές του κάτω από πραγματικές συνθήκες λειτουργίας του δικτύου, ενώ λαμβάνουν χώρα υποβάθμιση ποιότητας ή μη-διαθεσιμότητα στις δικτυακές ζεύξεις, παρέχοντας επίσης μετρικές από τη λειτουργία του δικτύου σε πραγματικό χρόνο.As the demand in mobile broadband is tremendously increased and the heterogeneity of the services to be covered is growing rapidly, current mobile networks are close to their limits imposing the need of an evolution which is going to be introduced by the next generation technology, the ITU IMT-2020, well known as 5G. 5G brings all those capabilities required to cover the increased mobile broadband needs, support the Internet of Things and bind heterogeneous services in different industries. This diploma thesis aims at presenting the “Network in a box”, an innovative tool we developed which is based on the key 5G principles, SDN and NFV. With Software Defined Networking (SDN) being the new approach in mobile networks, control and data plane are decoupled providing the ability to make any control related decisions centrally and transform legacy network devices to simple forwarding elements. This testbed is a portable emulated network device which is self-managed and self-optimised and can be connected between any real network devices, emulating how the 5G network will perform. This plug & play black-box testbed is also capable of providing KPI metrics of the 5G network under real circumstances when real network devices are connected to it. The structure of this diploma thesis is decomposed in five chapters. Chapter 1 presents the challenges mobile networks will shortly face due to the growing heterogeneous demands in communications towards the year 2020 and beyond and how these can be met with the upcoming 5G technology. Chapter 2 introduces the market trend behind the new era of 5G, revealing the business context for enterprises, consumers, verticals and partnerships as well as some use cases which reflect the continuous mobile broadband evolution. Chapter 3 includes a short overview of the ongoing 5G projects, initiated under the umbrella of the European Commission, with the collaboration of communications technology vendors, telecommunications operators, service providers, small and medium-sized enterprises (SMEs) and universities. There is also a reference in 5G key enabling technologies and standardisation activities as we move towards the next generation mobile networks technology. Moving forward, chapter 4 describes in detail the technological components of 5G network architecture such as SDN, NFV, MANO and examines how these 5G key enabling technologies contribute to the overall networks’ sustainability. Finally, in chapter 5 we introduce an innovative idea developed in our university’s communications network research laboratory, an autonomous emulated portable network testbed, the “Network in a box”. We present in-depth how this portable server is deployed, operates and demonstrate the way it can be connected to real network elements emulating a real 5G end-to-end customer network. Moreover, in this last chapter we present “Network in a box” capabilities under real network circumstances when link degradations or failures take place, providing also real-time network metrics

Network virtualization in next generation cellular networks

The complexity of operation and management of emerging cellular networks significantly increases, as they evolve to correspond to increasing QoS needs, data rates and diversity of offered services. Thus critical challenges appear regarding their performance. At the same time, network sustainability pushes toward the utilization of haring Radio Access Network (RAN) infrastructure between Mobile Network Operators (MNOs). This requires advanced network management techniques which have to be developed based on characteristics of these networks and traffic demands. Therefore it is necessary to provide solutions enabling the creation of logically isolated network partitions over shared physical network infrastructure. Multiple heterogeneous virtual networks should simultaneously coexist and support resource aggregation so as to appear as a single resource to serve different traffic types on demand. Hence in this thesis, we study RAN virtualization and slicing solutions destined to tackle these challenges. In the first part, we present our approach to map virtual network elements onto radio resources of the substrate physical network, in a dense multi-tier LTE-A scenario owned by a MNO. We propose a virtualization solution at BS level, where baseband modules of distributed BSs, interconnected via logical point-to-point X2 interface, cooperate to reallocate radio resources on a traffic need basis. Our proposal enhances system performance by achieving 53% throughput gain compared with benchmark schemes without substantial signaling overhead. In the second part of the thesis, we concentrate on facilitating resource provisioning between multiple Virtual MNOs (MVNOs), by integrating the capacity broker in the 3GPP network management architecture with minimum set of enhancements. A MNO owns the network and provides RAN access on demand to several MVNOs. Furthermore we propose an algorithm for on-demand resource allocation considering two types of traffic. Our proposal achieves 50% more admitted requests without Service Level Agreement (SLA) violation compared with benchmark schemes. In the third part, we devise and study a solution for BS agnostic network slicing leveraging BS virtualization in a multi-tenant scenario. This scenario is composed of different traffic types (e.g., tight latency requirements and high data rate demands) along with BSs characterized by different access and transport capabilities (i.e., Remote Radio Heads, RRHs, Small Cells, SCs and future 5G NodeBs, gNBs with various functional splits having ideal and non-ideal transport network). Our solution achieves 67% average spectrum usage gain and 16.6% Baseband Unit processing load reduction compared with baseline scenarios. Finally, we conclude the thesis by providing insightful research challenges for future works.La complejidad de la operación y la gestión de las emergentes redes celulares aumenta a medida que evolucionan para hacer frente a las crecientes necesidades de calidad de servicio (QoS), las tasas de datos y la diversidad de los servicios ofrecidos. De esta forma aparecen desafíos críticos con respecto a su rendimiento. Al mismo tiempo, la sostenibilidad de la red empuja hacia la utilización de la infraestructura de red de acceso radio (RAN) compartida entre operadores de redes móviles (MNO). Esto requiere técnicas avanzadas de gestión de redes que deben desarrollarse en función de las características especiales de estas redes y las demandas de tráfico. Por lo tanto, es necesario proporcionar soluciones que permitan la creación de particiones de red aisladas lógicamente sobre la infraestructura de red física compartida. Para ello, en esta tesis, estudiamos las soluciones de virtualización de la RAN destinadas a abordar estos desafíos. En la primera parte de la tesis, nos centramos en mapear elementos de red virtual en recursos de radio de la red física, en un escenario LTE-A de múltiples niveles que es propiedad de un solo MNO. Proponemos una solución de virtualización a nivel de estación base (BS), donde los módulos de banda base de BSs distribuidas, interconectadas a través de la interfaz lógica X2, cooperan para reasignar los recursos radio en función de las necesidades de tráfico. Nuestra propuesta mejora el rendimiento del sistema al obtener un rendimiento 53% en comparación con esquemas de referencia. En la segunda parte de la tesis, nos concentramos en facilitar el aprovisionamiento de recursos entre muchos operadores de redes virtuales móviles (MVNO), al integrar el capacity broker en la arquitectura de administración de red 3GPP con un conjunto míinimo de mejoras. En este escenario, un MNO es el propietario de la red y proporciona acceso bajo demanda (en inglés on-demand) a varios MVNOs. Además, para aprovechar al máximo las capacidades del capacity broker, proponemos un algoritmo para la asignación de recursos bajo demanda, considerando dos tipos de tráfico con distintas características. Nuestra propuesta alcanza 50% más de solicitudes admitidas sin violación del Acuerdo de Nivel de Servicio (SLA) en comparación con otros esquemas. En la tercera parte de la tesis, estudiamos una solución para el slicing de red independiente del tipo de BS, considerando la virtualización de BS en un escenario de múltiples MVNOs (multi-tenants). Este escenario se compone de diferentes tipos de tráfico (por ejemplo, usuarios con requisitos de latencia estrictos y usuarios con altas demandas de velocidad de datos) junto con BSs caracterizadas por diferentes capacidades de acceso y transporte (por ejemplo, Remote Radio Heads, RRHs, Small cells, SC y 5G NodeBs, gNBs con varias divisiones funcionales que tienen una red de transporte ideal y no ideal). Nuestra solución logra una ganancia promedio de uso de espectro de 67% y una reducción de la carga de procesamiento de la banda base de 16.6% en comparación con escenarios de referencia. Finalmente, concluimos la tesis al proporcionando los desafíos y retos de investigación para trabajos futuros.Postprint (published version