HDMM: deploying client and network-based distributed mobility management

Mobile operators are now facing the challenges posed by a huge data demand from users, mainly due to the introduction of modern portable devices and the success of mobile applications. Moreover, users are now capable to connect from different access networks and establish several active sessions simultaneously, while being mobile. This triggered the introduction of a new paradigm: the distributed mobility management (DMM) which aims at flattening the network and distributing the entities in charge of managing users' mobility. In this article, we review existing DMM proposals and describe a hybrid solution which benefits from combining a network-based and a client-based approach. We analyze the signaling cost and the handover latency of our proposal, comparing them with their centralized alternatives. We also include validation and performance results from experiments conducted with a Linux-based prototype, which show that achievable enhancements depend on the underlying network topology. We argue that the proposed hybrid DMM solution provides additional flexibility to the mobile network operators, which can decide when and how to combine these two approaches.The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7-ICT-2009-5) under Grant agreement n. 258053 (MEDIEVAL project) and from the Spanish Government, MICINN, under research grant TIN2010-20136-C0

An overview of internet engineering task force mobility management protocols: approaches and its challenges

In recent years, internet protocol mobility management has become one of the most popular research areas in networking. Mobility management protocols are in charge of preserving continuing communications as a user roam between different networks. All existing internet protocols (IP), like MIPv6, and PMIPv6, rely on a centralized mobility anchor to control mobile node traffic and signaling. The disadvantages of centralized mobility management (CMM) include ineffectiveness in handling massive volumes of traffic, poor scalability, wasteful use of network resources, and packet delay. When CMM is required to handle mobile media, which demands a huge amount of information and frequently needs quality of services (QoS) such as session continuance and reduced latency, these difficulties become apparent. It drives the need for distributed mobility management protocol (DMM) systems to manage the growing amount of mobile data, the overwhelming of this is video communication. DMM approaches could be regarded as an innovative and effective method to deal with mobility. An overview of the CMM protocol and its drawbacks are analyzed. This study examines the various DMM protocol techniques and their performance metrics are compared to highlight similarities and differences. The study reveals the network-based DMM protocol improves overall handoff time and packet loss

Distributed IP mobility management for hosts and networks

Includes bibliographical references.The Internet was originally designed for stationary nodes. With the advancement of mobile nodes (such as smartphones and tablets) that have wireless Internet access capability, the original design of the Internet is no longer sufficient. These mobile nodes are capable of communicating while moving and changing their point of attachment in the Internet. To maintain communication session(s) continuity for these mobile nodes, the Internet needs mobility management mechanisms. The main mobility management protocols standardised by the Internet Engineering Task Force (IETF) are mobile IP (MIPv6 and MIPv4) and their numerous extensions and variants, including proxy MIP (PMIPv6 and PMIPv4). The architectural structures of these protocols employ a centralized mobility anchor to manage the mobility of the mobile nodes in the control and data planes. The mobility anchor manages the mobility binding information and the forwarding of data packets for all mobile nodes registered in the network. However, in the context of the rapid growth in the number of mobile users and the data traffic volume, as well as the trend towards a flat architecture in mobile networks, the centralized mobility management approach provides insufficient mobility support to the mobile nodes. For example, to manage the demand for increased mobile users, a huge amount of data traffic will be pushed to the centralized mobility anchor. Yet, routing huge volumes of traffic via the centralized mobility anchor can be non-optimal in terms of routing efficiency. Thus, the centralised mobility anchor can be a potential bottleneck, and a single point of failure. Consequently, failure of the mobility anchor may lead to a service outage for a large number of mobile nodes. Ultimately, the centralized mobility management approach does not scale well with the increase in number of mobile users and the data traffic volume. These problems are also costly to resolve within the centralized mobility management approach and its related centralized network architecture. Distributed mobility management (DMM) is one recent approach that can efficiently address the shortcomings of centralized mobility management. It provides an alternative paradigm for developing IP mobility management – without employing centralized mobility anchors. In this paradigm, either the mobility anchors, or their mobility management functions, are distributed to different networks/elements. The mobility anchors, or the mobility management functions, are brought to the edge of the networks, which is closer to the mobile nodes. Distributed mobility management also offers dynamic mobility features that allow a mobile node to anchor traffic at different mobility anchors. However, to date, mobility management schemes that have been developed based on the DMM approach are still in the preliminary stages, and there is no current standard in place. These developed DMM schemes are still experiencing problems, such as long routing paths, especially for long-lasting data traffic, a lack of route optimization for ongoing communication, and a lack of synchronization of the mobile nodes‟ location in different networks. Moreover, the majority of these proposed schemes still need to be analysed, in order to quantify their feasibility. The thesis proposes three novel network-based distributed mobility management schemes, which are based on the DMM approach. The schemes enhance PMIPv6 to work in a distributed manner, in order to address the problems of centralized mobility management. Furthermore, the schemes address the following issues: (1) the lack of route optimization for ongoing communication; (2) the lack of synchronization of the mobile nodes‟ location in different networks; and (3) the long end-to-end packet delivery delay problems in recently proposed DMM schemes. The first scheme, called the network-based distributed mobility management scheme with routing management function at the gateways (DM-RMG), decomposes the logical mobility management functions of the Local Mobility Anchor (LMA) in PMIPv6 into internetwork location management (LM), routing management (RM), and home network prefix allocation (HNP) functions. After the decomposition, the RM function is collocated at the gateways of different networks. In this way, the data-plane routing function of the respective mobile nodes is served by the corresponding local RM function at the network gateway. The DM-RMG scheme offers distributed mobility management for individual mobile nodes (i.e., mobile hosts) during mobility events. DM-RMG also implements a mechanism to optimize the handover delay. The results obtained from analytical modelling and simulation show that the DM-RMG scheme outperforms the centralized mobility management schemes, as well as currently proposed distributed mobility management schemes in terms of the end-to-end packet delivery delay under different network load conditions. The optimized handover performance of the DM-RMG scheme, investigated under different traffic patterns and mobile node speeds, shows that the scheme also mitigates the internetwork handover delay and packet loss. The second proposed scheme, called network-based distributed mobility management for the network mobility (NDM-RMG), uses a similar approach to DM-RMG. However, it proposes a network-based DMM scheme for Network Mobility (NEMO). The main goal of the NDMRMG scheme is to address the problems of centralized mobility management protocols for NEMO, including the pinball routing problem in nested NEMO. NDM-RMG is compared with centralized mobility management schemes for NEMO, and recently proposed distributed IP mobility management schemes for NEMO by means of analytical modelling and simulation evaluations. NDM-RMG shows better performance in terms of reducing the packet delivery latency, the size of the packet header, and the packet overhead experienced over the wireless link. The third proposed scheme, called network-based distributed mobility management scheme with RM and HNP allocation functions distributed to the access routers (DM-RMA), distributes the RM and the HNP allocation functions at the access routers with the mobility client function. This brings the mobility-related functions closer to the mobile nodes, that is, to the edge of the network. An analytical model is developed to investigate the mobility cost performance of the scheme, due to signalling, packet delivery, and tunnelling. The analytical results indicate that DM-RMA performs better than the previous DMM schemes in terms of packet delivery, tunnelling and total costs. Network simulator-2 (ns-2) is used to model the DM-RMA scheme. The simulated scenarios confirm that DM-RMA performs better than other proposed DMM schemes in terms of reducing the location update latency at the location managers, end-to-end packet delivery delay, handover delay, and packet loss. In addition to the three proposed DMM schemes, this thesis proposes a routing optimization scheme for PMIPv6. The main goal of this scheme is to enable PMIPv6 to offer route optimization to mobile nodes in a PMIPv6 domain. The scheme reduces the route optimization-establishment latency, the packet delivery latency, and the packet loss. Using ns-2 simulations and considering different simulated scenarios, the results show that the scheme reduces route optimization-establishment latency and delayed packets during the route optimization operation, as compared to previously proposed PMIPv6 route optimization schemes. The results also show that the scheme reduces packet loss when a mobile node undergoes handover in the PMIPv6 domain

Analysis, design and experimental evaluation of connectivity management in heterogeneous wireless environments

Mención Internacional en el título de doctorThe future of network communications is mobile as many more users demand for ubiquitous connectivity. Wireless has become the primary access technology or even the only one, leading to an explosion in traffic demand. This challenges network providers to manage and configure new requirements without incrementing costs in the same amount. In addition to the growth in the use of mobile devices, there is a need to operate simultaneously different access technologies. As well, the great diversity of applications and the capabilities of mobile terminals makes possible for us to live in a hyper-connected world and offers new scenarios. This heterogeneity poses great challenges that need to be addressed to offer better performance and seamless experience to the final user. We need to orchestrate solutions to increase flexibility and empower interoperability. Connectivity management is handled from different angles. In the network stack, mobility is more easily handled by IP mobility protocols, since IP is the common layer between the different access technologies and the application diversity. From the end-user perspective, the connection manager is in charge of handling connectivity issues in mobile devices, but it is an unstandardized entity so its performance is heavily implementation-dependent. In this thesis we explore connectivity management from different angles. We study mobility protocols as they are part of our proposed solutions. In most of the cases we include an experimental evaluation of performance with 3G and IEEE 802.11 as the main technologies. We consider heterogeneous scenarios, with several access technologies where mobile devices have also several network interfaces. We evaluate how connectivity is handled as well as its influence in a handover. Based on the analysis of real traces from a cellular network, we confirm the suitability of more efficient mobility management. Moreover, we propose and evaluate three different solutions for providing mobility support in three different heterogeneous scenarios. We perform an experimental evaluation of a vehicular route optimization for network mobility, reporting on the challenges and lessons learned in such a complicated networking environment. We propose an architecture for supporting mobility and enhance handover in a passive optical network deployment. In addition, we design and deploy a mechanism for mobility management based on software-defined networking.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Arturo Azcorra Saloña.- Secretario: Ramón Agüero Calvo.- Vocal: Daniel Nunes Coruj

Algorithmes d'adressage et routage pour des réseaux fortement mobiles à grande échelle

After successfully connecting machines and people later (world wide web), the new era of In-ternet is about connecting things. Due to increasing demands in terms of addresses, mobility, scalability, security and other new unattended challenges, the evolution of current Internet archi-tecture is subject to major debate worldwide. The Internet Architecture Board (IAB) workshop on Routing and Addressing report described the serious scalability problems faced by large backbone operators in terms of routing and addressing, illustrated by the unsustainable growth of the Default Free Zone (DFZ) routing tables. Some proposals tackled the scalability and IP semantics overload issues with two different approaches: evolutionary approach (backward com-patibility) or a revolutionary approach. Several design objectives (technical or high-level) guided researchers in their proposals. Mobility is definitely one of the main challenges.Inter-Vehicle Communication (IVC) attracts considerable attention from the research com-munity and the industry for its potential in providing Intelligent Transportation Systems (ITS) and passengers services. Vehicular Ad-Hoc Networks (VANETs) are emerging as a class of wire-less network, formed between moving vehicles equipped with wireless interfaces (cellular and WiFi) employing heterogeneous communication systems. A VANET is a form of mobile ad-hoc network that provides IVC among nearby vehicles and may involve the use of a nearby fixed equipment on the roadside. The impact of Internet-based vehicular services (infotainment) are quickly developing. Some of these applications, driver assistance services or traffic reports, have been there for a while. But market-enabling applications may also be an argument in favor of a more convenient journey. Such use cases are viewed as a motivation to further adoption of the ITS standards developed within IEEE, ETSI, and ISO.This thesis focuses on applying Future Internet paradigm to vehicle-to-Internet communica-tions in an attempt to define the solution space of Future Vehicular Internet. We first introduce two possible vehicle-to-Internet use cases and great enablers for IP based services : eHealth and Fully-electric Vehicles. We show how to integrate those use cases into IPv6 enabled networks. We further focus on the mobility architectures and determine the fundamental components of a mobility architecture. We then classify those approaches into centralized and distributed to show the current trends in terms of network mobility extension, an essential component to vehicular networking. We eventually analyze the performance of these proposals. In order to define an identifier namespace for vehicular communications, we introduce the Vehicle Identification Numbers are possible candidates. We then propose a conversion algorithm that preserves the VIN characteristics while mapping it onto usable IPv6 networking objects (ad-dresses, prefixes, and Mobile Node Identifiers). We make use of this result to extend LISP-MN protocol with the support of our VIN6 addressing architecture. We also apply those results to group IP-based communications, when the cluster head is in charge of a group of followers.Cette thèse a pour objectif de faire avancer l'état de l'art des communications basée sur Internet Protocol version 6 (IPv6) dans le domaine des réseaux véhiculaires, et ce dans le cadre des évolutions récentes de IP, notamment l'avènement du Future Internet. Le Future Internet (F.I.) définit un ensemble d'approches pour faire évoluer l'Internet actuel , en particulier l'émergence d'un Internet mobile exigeant en ressources. Les acteurs de ce domaine définissent les contraintes inhérentes aux approches utilisées historiquement dans l'évolution de l'architecture d'Internet et tentent d'y remédier soit de manière évolutive soit par une rupture technologique (révolutionnaire). Un des problèmes au centre de cette nouvelle évolution d'Internet est la question du nommage et de l'adressage dans le réseau. Nous avons entrepris dans cette thèse l'étude de ce problème, dans le cadre restreint des communications véhiculaires Internet.Dans ce contexte, l'état de l'art du Future Internet a mis en avant les distinctions des approches révolutionnaires comparées aux propositions évolutives basées sur IPv6. Les réseaux véhiculaires étant d'ores-et-déjà dotés de piles protocolaires comprenant une extension IPv6, nous avons entamé une approche évolutive visant à intégrer les réseaux véhiculaires au Future Internet. Une première proposition a été de convertir un identifiant présent dans le monde automobile (VIN, Numéro d'Identification de Véhicule) en un lot d'adresses réseau propres à chaque véhicule (qui est donc propriétaire de son adressage issu de son identifiant). Cette proposition étant centrée sur le véhicule, nous avons ensuite intégré ces communications basés dans une architecture globale Future Internet basée sur IPv6 (protocole LISP). En particulier, et avec l'adressage VIN, nous avons défini un espace d'adressage indépendant des fournisseurs d'accès à Internet où le constructeur automobile devient acteur économique fournissant des services IPv6 à sa flotte de véhicules conjointement avec les opérateurs réseau dont il dépend pour transporter son trafic IP. Nous nous sommes ensuite intéressés à l'entourage proche du véhicule afin de définir un nouveau mode de communication inter-véhiculaire à Internet: le V2V2I (Angl. Vehicle-to-Vehicle-to-Infrastructure). Jusqu'à présent, les modes de transmission de données à Internet dans le monde du véhicule consistaient en des topologies V2I, à savoir véhicule à Internet, où le véhicule accède à l'infrastructure directement sans intermédiaire. Dans le cadre des communications véhiculaires à Internet, nous proposons une taxonomie des méthodes existantes dans l'état de l'art. Les techniques du Future Internet étant récentes, nous avons étendu notre taxonomie par une nouvelle approche basée sur la séparation de l'adressage topologique dans le cluster de celui de l'infrastructure. Le leader du cluster s'occupe d'affecter les adresses (de son VIN) et de gérer le routage à l'intérieur de son cluster. La dernière contribution consiste en la comparaison des performances des protocoles de gestion de mobilité, notamment pour les réseaux de véhicules et des communications de type vehicule-à-Internet. Dans ce cadre, nous avons proposé une classification des protocoles de gestion de mobilité selon leur déploiement: centralisé (basé réseau ou host) et distribué. Nous avons ensuite évalué les performances en modélisant les durées de configurations et de reconfigurations des différents protocoles concernés

A Survey and Future Directions on Clustering: From WSNs to IoT and Modern Networking Paradigms

Many Internet of Things (IoT) networks are created as an overlay over traditional ad-hoc networks such as Zigbee. Moreover, IoT networks can resemble ad-hoc networks over networks that support device-to-device (D2D) communication, e.g., D2D-enabled cellular networks and WiFi-Direct. In these ad-hoc types of IoT networks, efficient topology management is a crucial requirement, and in particular in massive scale deployments. Traditionally, clustering has been recognized as a common approach for topology management in ad-hoc networks, e.g., in Wireless Sensor Networks (WSNs). Topology management in WSNs and ad-hoc IoT networks has many design commonalities as both need to transfer data to the destination hop by hop. Thus, WSN clustering techniques can presumably be applied for topology management in ad-hoc IoT networks. This requires a comprehensive study on WSN clustering techniques and investigating their applicability to ad-hoc IoT networks. In this article, we conduct a survey of this field based on the objectives for clustering, such as reducing energy consumption and load balancing, as well as the network properties relevant for efficient clustering in IoT, such as network heterogeneity and mobility. Beyond that, we investigate the advantages and challenges of clustering when IoT is integrated with modern computing and communication technologies such as Blockchain, Fog/Edge computing, and 5G. This survey provides useful insights into research on IoT clustering, allows broader understanding of its design challenges for IoT networks, and sheds light on its future applications in modern technologies integrated with IoT.acceptedVersio

Distributed mobility management for a flat architecture in 5G mobile networks: solutions, analysis and experimental validation

In the last years, the commercial deployment of data services in mobile networks has been evolving quickly, providing enhanced radio access technologies and more efficient network architectures. Nowadays, mobile users enjoy broadband and ubiquitous wireless access through their portable devices, like smartphones and tablets, exploiting the connectivity offered by the modern 4G network. Nevertheless, the technological evolution keeps moving towards the development of next generation networks, or 5G, aiming at further improving the current system in order to cope with the huge data traffic growth foreseen in the future years. One of the possible research guidelines aims at innovating the mobile networks architecture by designing a flat system. Indeed, current systems are built upon a centralized and hierarchical structure, where multiple access networks are connected to a central core hosting crucial network functions, e.g., charging, control and maintenance, as well as mobility management, which is the main topic of this thesis. In such a central mobility management system, users’ traffic is aggregated at some key nodes in the core, called mobility anchors. Thus, an anchor can easily handle user’s mobility by redirecting traffic flows to his/her location, but i) it poses scalability issues, ii) it represents a single point of failure, and iii) the routing path is in general suboptimal. These problems can be overcome moving to a flat architecture, adopting a Distributed Mobility Management (DMM) system, where the centralized anchor is removed. This thesis develops within the DMM framework, presenting the design, analysis, implementation and experimental validation of several DMM protocols. In this work we describe original protocols for client-based and network-based mobility management, as well as a hybrid solution. We study analytically our solutions to evaluate their signaling cost, the packet delivery cost, and the latency introduced to handle a handover event. Finally, we assess the validity of some of our protocols with experiments run over a network prototype built in our lab implementing such solutions.El despliegue comercial de los servicios de datos en las redes móviles ha evolucionado rápidamente en los últimos años, proporcionando tecnologías de acceso radio más avanzadas y arquitecturas de red más eficientes. Los usuarios ya pueden disfrutar de los servicios de banda ancha desde sus dispositivos móviles, como smartphones y tablets, aprovechando la conectividad de las modernas redes 4G. Sin embargo, la evolución tecnológica sigue trazando su camino hasta el desarrollo de las redes de próxima generación, o 5G, en previsión del enorme aumento del tráfico de los años futuros. Una de las innovaciones bajo estudio aborda la arquitectura de las redes móviles, con el objetivo de diseñar un sistema plano. Efectivamente, el sistema actual se basa en una estructura centralizada y jerárquica, en la cual múltiples redes de acceso se conectan al núcleo central, dónde residen funciones cruciales para el control de la red y facturación, así como la gestión de la movilidad, que es el tema central de esta tesis. En un sistema con gestión centralizada de la movilidad, se agregan los flujos de tráfico en algunos nodos claves situados en el núcleo de la red, llamados anclas de movilidad. De este modo, un ancla puede fácilmente redirigir los flujos al lugar donde se halla el usuario, pero i) supone problemas de escalabilidad, ii) representa un punto único de fallo, y iii) el encaminamiento es en general sub-óptimo. Estos problemas se pueden resolver pasando a una arquitectura plana, cambiándose a un sistema de gestión distribuida de la movilidad (Distributed Mobility Management – DMM), donde no hay anclas centralizadas. Esta tesis se desarrolla dentro el marco propuesto por DMM, presentando el diseño, el análisis, la implementación y la validación experimental de varios protocolos de movilidad distribuida. Se describen soluciones basadas en el cliente y en la red, así como una solución híbrida. El funcionamiento de las soluciones ha sido estudiado analíticamente, para evaluar los costes de señalización, el coste del transporte de los paquetes y la latencia para gestionar el traspaso de los usuarios de una red a otra. Finalmente, la validez de los protocolos ha sido demostrada con experimentos sobre un prototipo donde se implementan algunas de las soluciones utilizando el equipamiento de nuestro laboratorio.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Arturo Azcorra Saloña.- Secretario: Ramón Agüero Calvo.- Vocal: Jouni Korhone

Descentralização da gestão da mobilidade IP nas redes do futuro

Doutoramento em Engenharia ElectrotécnicaThe massive adoption of sophisticated mobile devices and applications led to the increase of mobile data in the last decade, which it is expected to continue. This increase of mobile data negatively impacts the network planning and dimension, since core networks are heavy centralized. Mobile operators are investigating atten network architectures that distribute the responsibility of providing connectivity and mobility, in order to improve the network scalability and performance. Moreover, service providers are moving the content servers closer to the user, in order to ensure high availability and performance of content delivery. Besides the e orts to overcome the explosion of mobile data, current mobility management models are heavy centralized to ensure reachability and session continuity to the users connected to the network. Nowadays, deployed architectures have a small number of centralized mobility anchors managing the mobile data and the mobility context of millions of users, which introduces issues related to performance and scalability that require costly network mechanisms. The mobility management needs to be rethought out-of-the box to cope with atten network architectures and distributed content servers closer to the user, which is the purpose of the work developed in this Thesis. The Thesis starts with a characterization of mobility management into well-de ned functional blocks, their interaction and potential grouping. The decentralized mobility management is studied through analytical models and simulations, in which di erent mobility approaches distinctly distribute the mobility management functionalities through the network. The outcome of this study showed that decentralized mobility management brings advantages. Hence, it was proposed a novel distributed and dynamic mobility management approach, which is exhaustively evaluated through analytical models, simulations and testbed experiments. The proposed approach is also integrated with seamless horizontal handover mechanisms, as well as evaluated in vehicular environments. The mobility mechanisms are also speci ed for multihomed scenarios, in order to provide data o oading with IP mobility from cellular to other access networks. In the pursuing of the optimized mobile routing path, a novel network-based strategy for localized mobility is addressed, in which a replication binding system is deployed in the mobility anchors distributed through the access routers and gateways. Finally, we go further in the mobility anchoring subject, presenting a context-aware adaptive IP mobility anchoring model that dynamically assigns the mobility anchors that provide the optimized routing path to a session, based on the user and network context. The integration of dynamic and distributed concepts in the mobility management, such as context-aware adaptive mobility anchoring and dynamic mobility support, allow the optimization of network resources and the improvement of user experience. The overall outcome demonstrates that decentralized mobility management is a promising direction, hence, its ideas should be taken into account by mobile operators in the deployment of future networks.Na última década verificou-se uma massificação dos dispositivos móveis e das suas aplicações, o que tem vindo a aumentar o consumo de dados móveis. Este aumento dificulta o planeamento e dimensionamento das redes devido principalmente aos modelos extremamente centralizados adoptados por estas. Os operadores móveis têm vindo a estudar modelos mais até para as redes, os quais distribuem a responsabilidade de fornecer conectividade e mobilidade, no sentido de melhorar a escalabilidade e desempenho da rede. Além disso, de forma a garantir um desempenho elevado na entrega dos conteúdos, os fornecedores de serviço têm vindo a mover os servidores de conteúdos para locais mais próximos do utilizador. Apesar do esforço na procura de soluções para o crescente consumo de dados móveis, os modelos atuais de gestão de mobilidade são demasiado centralizados para conseguir assegurar a continuidade de sessão aos utilizadores conectados à rede. As arquiteturas implementadas têm um número muito reduzido de âncoras móveis centralizadas que gerem todos os dados móveis e a informação de contexto da mobilidade, o que leva a uma diminuição de desempenho e escalabilidade, solucionadas através de mecanismos de rede dispendiosos. A gestão da mobilidade precisa de ser repensada de forma a poder lidar com arquiteturas de rede até com a distribuição dos servidores de conteúdos para nós mais próximos dos utilizadores, que é o objectivo principal da Tese apresentada. Primeiro, é apresentada a caracterização da gestão de mobilidade em blocos funcionais, a interação entre eles e potenciais agrupamentos dos mesmos. A gestão da mobilidade descentralizada é estudada através de modelos analíticos e simulações, em que diferentes abordagens distribuem as funcionalidades da mobilidade pela rede. Como resultado deste estudo verificou-se que a descentralização da mobilidade traz vantagens claras. Com base nestes resultados foi proposta uma nova abordagem de gestão de mobilidade distribuída e dinâmica, que é exaustivamente avaliada através de modelos analíticos, simulações e experiências numa bancada de testes. A abordagem proposta é também integrada com mecanismos de handovers horizontais transparentes, assim como é avaliada em ambientes veiculares. Os mecanismos de mobilidade da abordagem proposta são também especificados para cenários de multihoming, de forma a proporcionar o offloading de dados com suporte de mobilidade das redes celulares para outras redes de acesso. Com o objectivo de optimizar o encaminhamento de dados móveis, foi criada uma nova estratégia para o suporte da mobilidade localizada, em que um sistema de replicação de bindings é integrado nas âncoras de mobilidade distribuídas através dos routers de acesso e dos gateways. Finalmente apresenta-se um modelo de ancoramento adaptativo para a mobilidade com base em contexto, o qual dinamicamente determina as âncoras de mobilidade que oferecem a melhor rota para uma dada sessão, baseado na informação do utilizador e da rede. A integração de conceitos de dinamismo e de distribuição na gestão da mobilidade, como o ancoramento adaptativo e o suporte dinâmico da mobilidade, permitem a optimização dos recursos da rede e uma melhor experiência por parte do utilizador. Os resultados demonstram, de uma forma geral, que a gestão descentralizada da mobilidade é um caminho promissor, logo este deve ser tomado em consideração pelas operadoras móveis aquando do desenvolvimento das redes do futuro

Towards Massive Machine Type Communications in Ultra-Dense Cellular IoT Networks: Current Issues and Machine Learning-Assisted Solutions

The ever-increasing number of resource-constrained Machine-Type Communication (MTC) devices is leading to the critical challenge of fulfilling diverse communication requirements in dynamic and ultra-dense wireless environments. Among different application scenarios that the upcoming 5G and beyond cellular networks are expected to support, such as eMBB, mMTC and URLLC, mMTC brings the unique technical challenge of supporting a huge number of MTC devices, which is the main focus of this paper. The related challenges include QoS provisioning, handling highly dynamic and sporadic MTC traffic, huge signalling overhead and Radio Access Network (RAN) congestion. In this regard, this paper aims to identify and analyze the involved technical issues, to review recent advances, to highlight potential solutions and to propose new research directions. First, starting with an overview of mMTC features and QoS provisioning issues, we present the key enablers for mMTC in cellular networks. Along with the highlights on the inefficiency of the legacy Random Access (RA) procedure in the mMTC scenario, we then present the key features and channel access mechanisms in the emerging cellular IoT standards, namely, LTE-M and NB-IoT. Subsequently, we present a framework for the performance analysis of transmission scheduling with the QoS support along with the issues involved in short data packet transmission. Next, we provide a detailed overview of the existing and emerging solutions towards addressing RAN congestion problem, and then identify potential advantages, challenges and use cases for the applications of emerging Machine Learning (ML) techniques in ultra-dense cellular networks. Out of several ML techniques, we focus on the application of low-complexity Q-learning approach in the mMTC scenarios. Finally, we discuss some open research challenges and promising future research directions.Comment: 37 pages, 8 figures, 7 tables, submitted for a possible future publication in IEEE Communications Surveys and Tutorial

Telecommunications Networks

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing