Technologies of Mobile Communication

Long-Term Evolution (LTE) is a new technology recently specified by 3GPP-Third Generation Partnership Project on the way towards fourth-generation mobile. This thesis presents the main technical features of this technology as well as its performances in terms of peak bit rate and average cell throughput, among others. LTE entails a big technological improvement as compared with the previous 3G standards. 1 However, this thesis also demonstrates that LTE performances do not fulfill the technical requirements established by ITU-R to classify one radio access technology as a member of the IMT-Advanced family of standards. Thus, this thesis describes the procedure followed by 3GPP to address these challenging requirements. Through the design and optimization of new radio access techniques and a further evolution of the system, 3GPP is laying down the foundations of the future LTE-Advanced standard, the 3GPP candidate for 4G

Context awareness and related challenges: A comprehensive evaluation study for a context-based RAT selection scheme towards 5G networks

Ο αποτελεσματικός σχεδιασμός των δικτύων είναι απαραίτητος για να αντιμετωπιστεί ο αυξανόμενος αριθμός των συνδρομητών κινητού διαδικτύου και των απαιτητικών υπηρεσιών δεδομένων, που ανταγωνίζονται για περιορισμένους ασύρματους πόρους. Επιπλέον, οι βασικές προκλήσεις για τα συνεχώς αναπτυσσόμενα δίκτυα LTE είναι η αύξηση των δυνατοτήτων των υφιστάμενων μηχανισμών, η μείωση της υπερβολικής σηματοδότησης (signaling) και η αξιοποίηση ενός αποτελεσματικού μηχανισμού επιλογής τεχνολογίας ασύρματης πρόσβασης (RAT). Υπάρχουν ποικίλες προτάσεις στην βιβλιογραφία σχετικά με αυτές τις προκλήσεις, μερικές από τις οποίες παρουσιάζονται εδώ. Ο σκοπός της εργασίας αυτής είναι να ερευνήσει τις τρέχουσες εξελίξεις στα δίκτυα LTE σχετικά με την ενσωμάτωση EPC και WiFi και την επίγνωση πλαισίου (context awareness) στην διαχείριση κινητικότητας, και να προτείνει τον αλγόριθμο COmpAsS, έναν μηχανισμό που χρησιμοποιεί ασαφή λογική (fuzzy logic) για να επιλέξει την πιο κατάλληλη τεχνολογία ασύρματης πρόσβασης για τα κινητά. Επιπλέον, έχουμε ποσοτικοποιήσει το κόστος σηματοδότησης του προτεινόμενου μηχανισμού σε σύνδεση με τις σημερινές προδιαγραφές του 3GPP και εκτελέσαμε μια ολοκληρωμένη ανάλυση. Τέλος, αξιολογήσαμε τον αλγόριθμο μέσω εκτεταμένων προσομοιώσεων σε ένα πολύπλοκο και ρεαλιστικό σενάριο χρήσης 5G, που απεικονίζονται τα σαφή πλεονεκτήματα της προσέγγισής μας όσον αφορά τη συχνότητα μεταπομπών (handover) και τις μετρήσεις βασικών QoS τιμών, όπως ρυθμός μετάδοσης και καθυστέρηση.Effective network planning is essential to cope with the increasing number of mobile internet subscribers and bandwidth-intensive services competing for limited wireless resources. Additionally, key challenges for the constantly growing LTE networks is increasing capabilities of current mechanisms, reduction of signaling overhead and the utilization of an effective Radio Access Technology (RAT) selection scheme. There have been various proposals in literature regarding these challenges, some of which are discussed here. The purpose of this work is to research the current advances in LTE networks regarding EPC - WiFi integration and context awareness in mobility management, and propose the COmpAsS algorithm, a mechanism using fuzzy logic to select the most suitable Radio Access Technology. Furthermore, we quantify the signaling overhead of the proposed mechanism by linking it to the current 3GPP specifications and performing a comprehensive analysis. Finally, we evaluate the novel scheme via extensive simulations in a complex and realistic 5G use case, illustrating the clear advantages of our approach in terms of handover frequency and key QoS metrics, i.e. the user-experienced throughput and delay

HUC-HISF: A Hybrid Intelligent Security Framework for Human-centric Ubiquitous Computing

制度:新 ; 報告番号:乙2336号 ; 学位の種類:博士(人間科学) ; 授与年月日:2012/1/18 ; 早大学位記番号:新584

Acesso banda larga sem fios em ambientes heterogéneos de próxima geração

Doutoramento em Engenharia InformáticaO acesso ubíquo à Internet é um dos principais desafios para os operadores de telecomunicações na próxima década. O número de utilizadores da Internet está a crescer exponencialmente e o paradigma de acesso "always connected, anytime, anywhere" é um requisito fundamental para as redes móveis de próxima geração. A tecnologia WiMAX, juntamente com o LTE, foi recentemente reconhecida pelo ITU como uma das tecnologias de acesso compatíveis com os requisitos do 4G. Ainda assim, esta tecnologia de acesso não está completamente preparada para ambientes de próxima geração, principalmente devido à falta de mecanismos de cross-layer para integração de QoS e mobilidade. Adicionalmente, para além das tecnologias WiMAX e LTE, as tecnologias de acesso rádio UMTS/HSPA e Wi-Fi continuarão a ter um impacto significativo nas comunicações móveis durante os próximos anos. Deste modo, é fundamental garantir a coexistência das várias tecnologias de acesso rádio em termos de QoS e mobilidade, permitindo assim a entrega de serviços multimédia de tempo real em redes móveis. Para garantir a entrega de serviços multimédia a utilizadores WiMAX, esta Tese propõe um gestor cross-layer WiMAX integrado com uma arquitectura de QoS fim-a-fim. A arquitectura apresentada permite o controlo de QoS e a comunicação bidireccional entre o sistema WiMAX e as entidades das camadas superiores. Para além disso, o gestor de cross-layer proposto é estendido com eventos e comandos genéricos e independentes da tecnologia para optimizar os procedimentos de mobilidade em ambientes WiMAX. Foram realizados testes para avaliar o desempenho dos procedimentos de QoS e mobilidade da arquitectura WiMAX definida, demonstrando que esta é perfeitamente capaz de entregar serviços de tempo real sem introduzir custos excessivos na rede. No seguimento das extensões de QoS e mobilidade apresentadas para a tecnologia WiMAX, o âmbito desta Tese foi alargado para ambientes de acesso sem-fios heterogéneos. Neste sentido, é proposta uma arquitectura de mobilidade transparente com suporte de QoS para redes de acesso multitecnologia. A arquitectura apresentada integra uma versão estendida do IEEE 802.21 com suporte de QoS, bem como um gestor de mobilidade avançado integrado com os protocolos de gestão de mobilidade do nível IP. Finalmente, para completar o trabalho desenvolvido no âmbito desta Tese, é proposta uma extensão aos procedimentos de decisão de mobilidade em ambientes heterogéneos para incorporar a informação de contexto da rede e do terminal. Para validar e avaliar as optimizações propostas, foram desenvolvidos testes de desempenho num demonstrador inter-tecnologia, composta pelas redes de acesso WiMAX, Wi-Fi e UMTS/HSPA.Ubiquitous Internet access is one of the main challenges for the telecommunications industry in the next decade. The number of users accessing the Internet is growing exponentially and the network access paradigm of “always connected, anytime, anywhere” is a central requirement for the so-called Next Generation Mobile Networks (NGMN). WiMAX, together with LTE, was recently recognized by ITU as one of the compliant access technologies for 4G. Nevertheless, WiMAX is not yet fully prepared for next generation environments, mainly due to the lack of QoS and mobility crosslayer procedures to support real-time multimedia services delivery. Furthermore, besides the 4G compliant WiMAX and LTE radio access technologies, UMTS/HSPA and Wi-Fi will also have a significant impact in the mobile communications during the next years. Therefore, it is fundamental to ensure the coexistence of multiple radio access technologies in what QoS and mobility procedures are concerned, thereby allowing the delivery of real-time services in mobile networks. In order to provide the WiMAX mobile users with the demanded multimedia services, it is proposed in this Thesis a WiMAX cross-layer manager integrated in an end-to-end all-IP QoS enabled architecture. The presented framework enables the QoS control and bidirectional communication between WiMAX and the upper layer network entities. Furthermore, the proposed cross-layer framework is extended with media independent events and commands to optimize the mobility procedures in WiMAX environments. Tests were made to evaluate the QoS and mobility performance of the defined architecture, demonstrating that it is perfectly capable of handling and supporting real time services without introducing an excessive cost in the network. Following the QoS and mobility extensions provided for WiMAX, the scope of this Thesis is broaden and a seamless mobility architecture with QoS support in heterogeneous wireless access environments is proposed. The presented architecture integrates an extended version of the IEEE 802.21 framework with QoS support, as well as an advanced mobility manager integrated with the IP level mobility management protocols. Finally, to complete the work within the framework of this Thesis, it is proposed an extension to the handover decisionmaking processes in heterogeneous access environments through the integration of context information from both the network entities and the enduser. Performance tests were developed in a real testbed to validate the proposed optimizations in an inter-technology handover scenario involving WiMAX, Wi-Fi and UMTS/HSPA

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

Mecanismos de offloading para redes móveis usando SDN em ambientes virtualizados

The exploding mobile data traffic increase in recent years has been putting a high load on both mobile cells and core network, with operators facing the need to upgrade their networks. Nowadays, to do this upgrade, operators need to purchase new specialized equipment for network functions, having to cope with a high upgrade CAPEX. Furthermore, networks are deployed with a one size fits all approach, which in some cases might not satisfy the requirements of specific services. 5G aims to solve these problems by virtualizing network functions in datacenters, decoupling the software from the hardware for network functions and using general purpose hardware instead. To support this, Software Defined Networking (SDN) is introduced, which allows the network to have a higher degree of programmability, enabling new features such as higher flexibility and network slicing, where multiple virtual networks can be created and tailored to specific requirements. This thesis addresses an architecture that evolves the Evolved Packet Core (EPC) into a core network closer to 5G by virtualizing EPC’s network functions, introducing SDN and supporting 4G to Wi-Fi traffic offloading, helping to reduce the load on mobile cells by leveraging on the smartphone’s support for dual connectivity and high density of Wi-Fi access points already deployed worldwide. The proposed architecture is then evaluated and compared to a vanilla EPC whenever possible showing that, although there is an increase in latency at the virtual EPC, the bottleneck of the system resides in the air interface. Also, a use case for this architecture was defined and evaluated. The use case considered traffic offloading and dynamic Wi-Fi slice creation, with results showing that it can seamlessly offload a video stream from 4G to Wi-Fi without affecting the user’s Quality of Experience.O explosivo aumento do tráfego móvel em anos recentes tem vindo a aumentar a carga nas células e núcleo da rede móvel, com os operadores a serem confrontados com a necessidade de atualizar as mesmas. Hoje em dia, para executar esta atualização, os operadores necessitam de adquirir equipamento novo e especializado para as funções de rede, levando a um grande CAPEX de atualização. Além disso, as redes são implementadas seguindo uma abordagem de uma solução única para todos os casos, o que nalguns pode não satisfazer os requisitos de serviços específicos. O 5G visa resolver estes problemas ao virtualizar funções de rede em datacenters, desacoplando o software do hardware para as funções de rede e ao utilizar hardware de uso geral. Para suportar isto, as redes definidas por software (SDN) são introduzidas, permitindo um maior grau de programabilidade na rede, e permitindo novas funcionalidades como maior flexibilidade e segmentação de rede, onde múltiplas redes virtuais podem ser criadas com requisitos específicos. Esta tese endereça uma arquitetura que evolui o Evolved Packet Core (EPC) para uma rede de core mais próxima do 5G ao virtualizar as funções de rede do EPC, introduzindo SDN e suportando Wi-Fi e "offloading" de tráfego da rede móvel para a rede Wi-Fi, auxiliando na redução da carga das células móveis ao tirar partido da capacidade de conectividade múltipla e da grande densidade de pontos de acesso implementados mundialmente. A arquitetura proposta é então avaliada e comparada com um EPC implementado numa máquina física sempre que possível mostrando que, apesar do aumento da latência no EPC virtualizado, a limitação do sistema é devida à interface de rádio. Um cenário para esta arquitetura é definido e avaliado, considerando o "offloading" de tráfego e instanciação dinâmica de redes segmentadas, com resultados a mostrar que o sistema consegue fazer um offload perfeito de tráfego de um stream de vídeo de 4G para Wi-Fi sem afetar a Qualidade de Experiência do utilizador.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Secure mobility at multiple granularity levels over heterogeneous datacom networks

The goal of this thesis is to define a set of changes to the TCP/IP stack that allow connections between legacy applications to be sustained in a contemporary heterogeneous datacom environment embodying multiple granularities of mobility. In particular, the thesis presents a number of solutions for flow mobility, local mobility, network mobility, and address family agility that is mobility between different IP versions. The presented mobility solutions are based on the so-called identifier-locator split approach. Due to the split, the mobile and multi-homed hosts that employ the presented solution are able to simultaneously communicate via multiple access networks, even supporting different IP versions and link layer technologies. In addition to the mobility solutions, the thesis also defines a set of weak and strong security mechanisms. They are used to protect the mobility protocols from redirection, Denial-of-Service (DoS), and privacy related attacks. The defined security mechanisms are tightly bound to the presented mobility architecture, providing alternative ways to optimize mobility management signalling. The focus is on minimizing end-to-end signalling latency, optimizing the amount of signalling and optimizing packet forwarding paths. In addition, the architecture provides identity and location privacy for hosts. The presented work defines one specific kind of engineering balance between the security, privacy, and efficient mobility signalling requirements. This thesis indicates that the added security, indirection, backwards compatibility, and inter-operable mobility solutions can overcome several of the current TCP/IP restrictions. The presented mobility architecture also provides a migration path from the existing Internet architecture to a new cryptographic-identifier-based architecture

Context-awareness for ubiquitous media service delivery in next generation networks

Les récentes avancées technologiques permettent désormais la fabrication de terminaux mobiles de plus en plus compacts et dotés de plusieurs interfaces réseaux. Le nouveau modèle de consommation de médias se résume par le concept "Anytime, Anywhere, Any Device" et impose donc de nouvelles exigences en termes de déploiement de services ubiquitaires. Cependant la conception et le developpement de réseaux ubiquitaires et convergents de nouvelles générations soulèvent un certain nombre de défis techniques. Les standards actuels ainsi que les solutions commerciales pourraient être affectés par le manque de considération du contexte utilisateur. Le ressenti de l'utilisateur concernant certains services multimédia tels que la VoIP et l'IPTV dépend fortement des capacités du terminal et des conditions du réseau d'accès. Cela incite les réseaux de nouvelles générations à fournir des services ubiquitaires adaptés à l'environnement de l'utilisateur optimisant par la même occasion ses resources. L'IP Multimedia Subsystem (IMS) est une architecture de nouvelle génération qui centralise l'accès aux services et permet la convergence des réseaux fixe/mobile. Néanmoins, l'évolution de l'IMS est nécessaire sur les points suivants :- l'introduction de la sensibilité au contexte utilisateur et de la PQoS (Perceived QoS) : L'architecture IMS ne prend pas en compte l'environnement de l'utilisateur, ses préférences et ne dispose pas d'un méchanisme de gestion de PQOS. Pour s'assurer de la qualité fournit à l'utilisateur final, des informations sur l'environnement de l'utilisateur ainsi que ses préférences doivent transiter en cœur de réseau afin d'y être analysés. Ce traitement aboutit au lancement du service qui sera adapté et optimisé aux conditions observées. De plus pour le service d'IPTV, les caractéristiques spatio-temporelles de la vidéo influent de manière importante sur la PQoS observée côté utilisateur. L'adaptation des services multimédias en fonction de l'évolution du contexte utilisateur et de la nature de la vidéo diffusée assure une qualité d'expérience à l'utilisateur et optimise par la même occasion l'utilisation des ressources en cœur de réseau.- une solution de mobilité efficace pour les services conversationnels tels que la VoIP : Les dernières publications 3GPP fournissent deux solutions de mobilité: le LTE proposeMIP comme solution de mobilité alors que l'IMS définit une mobilité basée sur le protocoleapplicatif SIP. Ces standards définissent le système de signalisation mais ne s'avancent pas sur la gestion du flux média lors du changement d'interface réseau. La deuxième section introduit une étude comparative détaillée des solutions de mobilité dans les NGNs.Notre première contribution est la spécification de l'architecture globale de notre plateforme IMS sensible au contexte utilisateur réalisée au sein du projet Européen ADAMANTIUM. Nous détaillons tout d'abord le serveur MCMS intelligent placé dans la couche application de l'IMS. Cet élément récolte les informations de qualité de services à différents équipements réseaux et prend la décision d'une action sur l'un de ces équipements. Ensuite nous définissons un profil utilisateur permettant de décrire son environnement et de le diffuser en coeur de réseau. Une étude sur la prédiction de satisfaction utilisateur en fonction des paramètres spatio-temporels de la vidéo a été réalisée afin de connaître le débit idéal pour une PQoS désirée.Notre deuxième contribution est l'introduction d'une solution de mobilité adaptée aux services conversationnels (VoIP) tenant compte du contexte utilisateur. Notre solution s'intègre à l'architecture IMS existante de façon transparente et permet de réduire le temps de latence du handover. Notre solution duplique les paquets de VoIP sur les deux interfaces actives pendant le temps de la transition. Parallèlement, un nouvel algorithme de gestion de mémoire tampon améliore la qualité d'expérience pour le service de VoIP.The latest advances in technology have already defied Moore s law. Thanks to research and industry, hand-held devices are composed of high processing embedded systems enabling the consumption of high quality services. Furthermore, recent trends in communication drive users to consume media Anytime, Anywhere on Any Device via multiple wired and wireless network interfaces. This creates new demands for ubiquitous and high quality service provision management. However, defining and developing the next generation of ubiquitous and converged networks raise a number of challenges. Currently, telecommunication standards do not consider context-awareness aspects for network management and service provisioning. The experience felt by the end-user consuming for instance Voice over IP (VoIP) or Internet Protocol TeleVision (IPTV) services varies depending mainly on user preferences, device context and network resources. It is commonly held that Next Generation Network (NGN) should deliver personalized and effective ubiquitous services to the end user s Mobile Node (MN) while optimizing the network resources at the network operator side. IP Multimedia Subsystem (IMS) is a standardized NGN framework that unifies service access and allows fixed/mobile network convergence. Nevertheless IMS technology still suffers from a number of confining factors that are addressed in this thesis; amongst them are two main issues :The lack of context-awareness and Perceived-QoS (PQoS):-The existing IMS infrastructure does not take into account the environment of the user ,his preferences , and does not provide any PQoS aware management mechanism within its service provisioning control system. In order to ensure that the service satisfies the consumer, this information need to be sent to the core network for analysis. In order to maximize the end-user satisfaction while optimizing network resources, the combination of a user-centric network management and adaptive services according to the user s environment and network conditions are considered. Moreover, video content dynamics are also considered as they significantly impact on the deduced perceptual quality of IPTV services. -The lack of efficient mobility mechanism for conversational services like VoIP :The latest releases of Third Generation Partnership Project (3GPP) provide two types of mobility solutions. Long-Term Evolution (LTE) uses Mobile IP (MIP) and IMS uses Session Initiation Protocol (SIP) mobility. These standards are focusing on signaling but none of them define how the media should be scheduled in multi-homed devices. The second section introduces a detailed study of existing mobility solutions in NGNs. Our first contribution is the specification of the global context-aware IMS architecture proposed within the European project ADAptative Management of mediA distributioN based on saTisfaction orIented User Modeling (ADAMANTIUM). We introduce the innovative Multimedia Content Management System (MCMS) located in the application layer of IMS. This server combines the collected monitoring information from different network equipments with the data of the user profile and takes adaptation actions if necessary. Then, we introduce the User Profile (UP) management within the User Equipment (UE) describing the end-user s context and facilitating the diffusion of the end-user environment towards the IMS core network. In order to optimize the network usage, a PQoS prediction mechanism gives the optimal video bit-rate according to the video content dynamics. Our second contribution in this thesis is an efficient mobility solution for VoIP service within IMS using and taking advantage of user context. Our solution uses packet duplication on both active interfaces during handover process. In order to leverage this mechanism, a new jitter buffer algorithm is proposed at MN side to improve the user s quality of experience. Furthermore, our mobility solution integrates easily to the existing IMS platform.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Localization and mobility management in heterogeneous wireless networks with network-assistance

The nowadays heterogeneous wireless network (HWN) is a collection of ubiquitous wireless networking elements (WNEs) that support diverse functional capabilities and networking purposes. In such a heterogeneous networking environment, localization and mobility management will play a key role for the seamless support of emerging applications, such as social networking, massive multiplayer online gaming, device-todevice (D2D) communications, smart metering, first-responder communications, and unsupervised navigation of communication-aware robotic nodes. Since most of the existing wireless networking technologies enable the WNEs to assess their current radio status and directly (or indirectly) estimate their relative distance and angle with respect to other WNEs of the same Radio Access Technology (RAT), the integration of such information from the ubiquitous WNEs arises as a natural solution for robustly handling localization between (not necessarily homogeneous) WNEs and mobility management of moving WNEs governed by resource-constrained operation. Under the viewpoint of investigating how the utilization of such spatial information can be used to enhance the performance of localization and mobility management in the nowadays HWN, in this work we focus and contribute in the following four research areas: i) localization and peer-discovery between non-homogeneous WNEs, ii) network-assisted D2D discovery in cellular networks, iii) energy-efficient handover (HO) decision in the macrocell – femtocell network, and iv) network-assisted vertical handover decision (VHO) for the integrated cellular and WLAN heterogeneous wireless network