The overarching goal of this thesis is to investigate network architectures, and find the trade-off between low overall energy use and maintaining the level of quality of service (QoS), or even improve it. The ubiquitous wireless communications environment supports the exploration of different network architectures and techniques, the so-called heterogeneous network. Two kinds of heterogeneous architectures are considered: a combined cellular and femtocell network and a combined cellular, femtocell and Wireless Local Area Network(WLAN) network. This thesis concludes that the investigated heterogeneous networks can significantly reduce the overall power consumption, depending on the uptake of femtocells and WLANs. Also, QoS remains high when the power consumption drops. The main energy saving is from reducing the macrocell base station embodied and operational energy. When QoS is evaluated based on the combined cellular and femtocell architecture, it is suggested that use of resource scheduling for femtocells within the macrocell is crucial since femtocell performance is affected significantly by interference when installed in a co-channel system. Additionally, the femtocell transmission power mode is investigated using either variable power level or a fixed power level. To achieve both energy efficiency and QoS, the choice of system configurations should change according to the density of the femtocell deployment. When combining deployment of femtocells with WLANs, more users are able to experience a higher QoS. Due to increasing of data traffic and smartphone usage in the future, WLANs are more important for offloading data from the macrocell, reducing power consumption and also increasing the bandwidth. The localised heterogeneous network is a promising technique for achieving power efficiency and a high QoS system.

La continuité de service est un élément important dans les communications mobiles. Avec la coexistence de différentes technologies d'accès au réseau et l'émergence de dispositifs mobiles avec plusieurs interfaces réseau, les fournisseurs de services doivent maintenir la communication en cours lorsque les mobiles voyagent entre des réseaux hétérogènes. Des services comme l'IPTV, vidéo à la demande ou la voix sur IP sont largement proposés par les opérateurs pour lesquels la continuité de service doit être garantie. Cette thèse est consacrée à la continuité du service pour des applications temps réel dans des réseaux hétérogènes. Nous abordons ce problème de deux perspectives: la mobilité de session et la mobilité de terminal. Bien que ces deux mécanismes aient le même but qui est d'assurer la continuité de service lors du changement de terminal ou de réseau d'accès, chaque technique a ses propres défis et contraintes. En ce qui concerne la mobilité de session, un nouveau protocole de signalisation a été proposé pour transférer la session entre les différents terminaux d’un utilisateur. Ce protocole a été conçu pour les scénarios de streaming vidéo. Son implémentation a permis la validation du protocole proposé ainsi que son évaluation. En outre, nous traitons le problème de l'adaptation des flux multimédias, notamment la renégociation des paramètres de la qualité de service puisque la session pourrait être transféré à un nouveau terminal avec des capacités différentes que le terminal d’origine. Cette renégociation peut être étendue pour couvrir le cas où certains paramètres internes sont dégradés au cours de la session dans le même terminal. Quand à la mobilité de terminal, nous proposons un mécanisme basé sur l’utilisation de la nouvelle norme IEEE802.21 et du protocole de mobilité FMIPv6. Le but de cette proposition est de réduire le délai du handover et la taille de l’espace mémoire dédiée au niveau des routeurs d'accès. En outre, une optimisation est proposée pour FMIPv6 afin de maximiser la probabilité de son mode prédictive. Dans le même contexte, la mobilité dans l’IP Multimédia Subsystem (IMS) est considéré et une solution adaptée est proposée pour répondre aux exigences de l’IMS. Enfin, nous menons une étude comparative entre les différentes variantes de Mobile IP dans le cas de handover vertical. En se basant sur cette comparaison, nous donnons quelques directives qui devraient aider à choisir le protocole le plus efficace suivant des paramètres spécifiques. Les solutions proposées et les études ont été évaluées avec des méthodes analytiques et/ou en faisant appel à des simulations. / Service continuity is an important component in mobile communications. With the coexistence of different access network technologies and the emergence of multi-interface mobile devices, service providers should maintain the ongoing communication when the mobile travels among heterogeneous networks. Services like IPTV, video on demand or voice over IP are widely proposed by operators for which service continuity should be guaranteed. This thesis is devoted to service continuity of real-time applications in heterogeneous networks. We tackle this problem from two perspectives: session mobility and terminal mobility. Although these two mechanisms have the same purpose which is ensuring service continuity when changing the terminal or the access network, each technique has its own challenges and constraints. As far as session mobility is concerned, a new signaling protocol has been proposed to transfer the session between different terminals. This protocol has been implemented in video streaming scenarios and evaluated in a testbed. Moreover, we address the problem of media adaptation, especially renegotiation of QoS parameters since session might be transferred to a new terminal with different capabilities than the original one. QoS renegotiation can be extended to cover the case where some internal parameters are degraded during the session in the same terminal. For terminal mobility, we propose a new handover mechanism using IEEE802.21 with Fast handover for Mobile IPv6. The purpose of this proposal is to reduce the handover delay and the dedicated buffer in access routers. In addition, an optimization is proposed for Fast handovers for Mobile IPv6 in order to maximize the probability of its predictive mode. In the same context, mobility in IMS is considered and an appropriate solution is proposed to answer IMS requirements. Finally, we conduct a comparison study between different mobile IP variants in the case of vertical handover. Based on this comparison, we give some guidelines that should help in choosing the most efficient protocol following specific parameters. The proposed solutions and studies have been evaluated analytically or/and using a simulation tool.

Nous assistons actuellement à une évolution considérable des communications mobiles. En l’absence d’accord entre les fournisseurs, changer son point d’attachement au réseau signifie encore casser la session en cours et dépendre de l'application pour récupérer les données perdues. De même, il n'est guère possible pour un utilisateur mobile de contrôler la connectivité de son appareil. L'objectif de cette thèse est de présenter le concept d'une structure technologique innovante pour le contrôle autonome des terminaux multimodes dans les environnements sans fil hétérogènes et non fédérés. Son but est de permettre à un terminal auto-configuré de se connecter et de se déplacer de manière transparente à travers des réseaux indépendants, tout en respectant les choix et préférences de son utilisateur. Le schéma obtenu implique des mécanismes d’abstraction et inter-couches. Il tient compte de contraintes basées sur les systèmes sans fil hétérogènes, les architectures autonomes, et permet l’exécution de services génériques comme le choix du réseau d'accès et la gestion de la connectivité et des sessions. Ce schéma s'applique au terminal mobile, avec des mécanismes dissociés de l'infrastructure réseau. La thèse analyse comment les technologies existantes sont améliorées et combinées avec de nouvelles fonctionnalités pour atteindre cet objectif, et donne une description de l'ensemble du concept et de sa mise en œuvre. Un modèle simulé est utilisé pour évaluer la validité de la structure proposée. Diverses applications à des systèmes réels mettant en œuvre les éléments de cette architecture sont présentées, faisant ressortir la généralité et les principaux avantages du concept. / Recent years have witnessed a massive evolution of mobile communications. When no agreement between the network providers exists, changing the attached network still means breaking the session and relying on the application to recover the lost data. In parallel, it is hardly possible for a mobile user to control the connectivity of his terminal. The objective of this thesis is to present the concept of an innovative technological framework for the autonomous control of multimode terminals in heterogeneous and non-federated wireless environments. The aim is to enable a self-configuring terminal to connect and roam seamlessly across independent networks, while respecting its user’s choices and preferences. The target scheme involves abstraction and cross-layer mechanisms. It takes into account constraints based on heterogeneous wireless systems, autonomous architectures and enables generic services such as smart access network selection, connectivity and session management. This scheme applies to the mobile terminal, with mechanisms independent of the network infrastructure. The thesis analyses how existing technologies are enhanced and combined with new features to achieve this objective and gives a description of the overall concept and of its implementation. A simulated model is used to assess the validity of the proposed framework. Diverse applications to real systems that implemented the components of this framework are presented, highlighting the generality and key benefits of the concept.

No description available.

Different techniques are being implemented in modern communication networks to ensure that their coverage, capacity, and other user-experience requirements are always met. In this thesis, I consider multi-antenna techniques, energy harvesting, and the dense deployment of small cell base stations in a two-tiered wireless powered communication network (WPCN) where multi-antenna transmitters utilize a Harvest Then Transmit (HTT) protocol to coordinate wireless energy harvesting and information transmission with their associated users. To satisfy network throughput requirements at all user positions, I formulate multi-constraint optimization problems to maximize the minimum data rate at both tier and network levels, solving the resulting non-convex expressions with an algorithm which incorporates the Perron-Frobenius non-negative matrix theory for alternate parameter optimization. I also present a less complex solution methodology, compared the performance of both and provided interesting insights on my findings. / October 2016

Data traffic demand has been increasing exponentially and this trend will continue over theforeseeable future. This has forced operators to upgrade and densify their mobile networks toenhance their capacity. Future networks will be characterized by a dense deployment of different kinds of base stations (BSs) in a hierarchical cellular structure. However network densification requires extensive capital and operational investment which limits operator revenues and raises ecological concerns over greenhouse gas emissions. Although networks are planned to support peak traffic, traffic demand is actually highly variable in both space and time which makes it necessary to adapt network energy consumption to inevitable variations in traffic demand. In this thesis, stochastic geometry tools are used to perform simple and tractable analysis of thecoverage, rate and energy performance of homogeneous networks and heterogeneous networks(HetNets). BSs in each tier are located according to independent Poisson Point Processes(PPPs) to generate irregular topologies that fairly resemble practical deployment topologies. The homogeneous network is optimized to determine the optimal BS density and transmit power configuration that minimizes its area power consumption (APC) subject to both coverage and average rate constraints. Results show that optimal transmit power only depends on the BSpower consumption parameters and can be predetermined. Furthermore, various sleep modemechanisms are applied to the homogeneous network to adapt its APC to changes in userdensity. A centralized strategic scheme which prioritize BSs with the least number of usersenhances energy efficiency (EE) of the network. Due to the complexity of such a centralizedscheme, a distributed scheme which implements the strategic algorithm within clusters of BSsis proposed and its performance closely matches that of its centralized counterpart. It is more challenging to model the optimal deployment configuration per tier in a multi-tier HetNet. Appropriate assumptions are used to determine tight approximations of these deployment configurations that minimize the APC of biased and unbiased HetNets subject tocoverage and rate constraints. The optimization is performed for three different user associationschemes. Similar to the homogeneous network, optimal transmit power per tier also depends onBS power consumption parameters only and can also be predetermined. Analysis of the effect of biasing on HetNet performance shows appropriate biasing can further reduce the deploymentconfiguration (and consequently the APC) compared to an unbiased HetNet. In addition, biasing can be used to offload traffic from congesting and high-power macro BSs to low-power small BSs. If idle BSs are put into sleep mode, more energy is saved and HetNet EE improves. Moreover, appropriate biasing also enhances the EE of the HetNet.

Wireless sensor networks (WSNs) is a virtual layer in the paradigm of the Internet of Things (IoT). It inter-relates information associated with the physical domain to the IoT drove computational systems. WSN provides an ubiquitous access to location, the status of different entities of the environment, and data acquisition for long-term IoT monitoring. Since energy is a major constraint in the design process of a WSN, recent advances have led to project various energy-efficient protocols. Routing of data involves energy expenditure in considerable amount. In recent times, various heuristic clustering protocols have been discussed to solve the purpose. This article is an improvement of the existing stable election protocol (SEP) that implements a threshold-based cluster head (CH) selection for a heterogeneous network. The threshold maintains uniform energy distribution between member and CH nodes. The sensor nodes are also categorized into three different types called normal, intermediate, and advanced depending on the initial energy supply to distribute the network load evenly. The simulation result shows that the proposed scheme outperforms SEP and DEEC protocols with an improvement of 300% in network lifetime and 56% in throughput.

No description available.

The concept of Software Defined Networking (SDN) may be a way to face the fast growing computer network infrastructure with its demands and requirements. The concept is attracting the interest of enterprises to expand their respective network infrastructures, but one has to consider the impacts of migrating from an existing network infrastructure to an SDN network. One way that could minimize the impacts is to proceed a soft migration from a traditional IP network to SDN, creating what is so called a heterogeneous network. Instead of fully replacing the network infrastructure and face the impacts of it, the idea of the soft migration is to replace a part of it with an environment of SDN and examine the performance of it. This thesis work will analyze the performance of a network consisting of a traditional IP network combined with SDN. It is essential during this work to identify the differences in performance when having a heterogeneous network in comparison with having a dedicated traditional IP network. Therefore, the questions that will be addressed during this thesis work is to examine how such a heterogeneous network can be designed and measure the performance of it in terms of throughput, jitter and packet losses. By the method of experimentation and the studying of related works of the SDN fundamentals, we hope to achieve our goals with this thesis work, to give us and the reader a clearer insight.

Based on the targets outlined by the EU Horizon 2020 (H2020) framework, it is expected that heterogeneous networking will play a crucial role in delivering seamless end-to-end ubiquitous Internet access for users. In due course, the current GSM-Railway (GSM-R) will be deemed unsustainable, as the demand for packet-oriented services continues to increase. Therefore, the opportunity to identify a plausible replacement system conducted in this research study is timely and appropriate. In this research study, a hybrid satellite and terrestrial network for enabling ubiquitous Internet access in a high-speed train environment is investigated. The study focuses on the mobility management aspect of the system, primarily related to the handover management. A proposed handover strategy, employing the RACE II MONET and ITU-T Q.65 design methodology, will be addressed. This includes identifying the functional model (FM) which is then mapped to the functional architecture (FUA), based on the Q.1711 IMT-2000 FM. In addition, the signalling protocols, information flows and message format based on the adopted design methodology will also be specified. The approach is then simulated in OPNET and the findings are then presented and discussed. The opportunity of exploring the prospect of employing neural networks (NN) for handover is also undertaken. This study focuses specifically on the use of pattern classification neural networks to aid in the handover process, which is then simulated in MATLAB. The simulation outcomes demonstrated the effectiveness and appropriateness of the NN algorithm and the competence of the algorithm in facilitating the handover process.