Dense deployment of small cells underlaying the traditional macrocells is considered as a key enabling technique for the emerging fifth generation (5G) cellular networks. However, the diverse transmit powers of the base stations (BSs) in such a network lead to uneven distribution of the traffic loads among different BSs when received signal power (RSP)-based user association is used. Moreover, provisioning of efficient and economical backhauling for these small cells is a crucial challenge. To combat this, wireless backhauling is been considered as a viable and cost-effective approach that allows operators to obtain end-to-end control of their network rather than leasing third party wired backhaul connections. But the scarcity of radio frequency (RF) spectrum in the licensed bands is still a major constraint which necessitates efficient spectrum planning for backhaul/access links of small cells. Emerging communications techniques such as full-duplexing, which allows transmission and reception in the same spectrum band, can be used to tackle the problem of spectrum scarcity. In the above contexts, the objective of the research work presented in this thesis is to develop efficient user association and wireless backhauling schemes for small cell networks and analyze their performances. In particular, i) A channel-access aware user association scheme is proposed to tackle the problem of uneven distribution of traffic load among different BSs, ii) Performance analysis of full-duplex (FD) wireless backhauling of small cells is carried out when compared to half-duplex (HD) wireless backhauling), iii) A method for downlink spectrum allocation for in-band and out-of-band wireless backhauling of full-duplex small cells is presented to optimally allocate spectrum for access and backhaul links, iv) A method for optimal channel and power allocation is presented for downlink access and backhaul links for half-duplex small cells. The proposed methods and performance analysis models will be useful for optimizing the design and deployment of small cell networks. / October 2017

In multi-tier cellular networks, user performance is largely a ected by the varying transmit powers, distances, and non-uniform tra c loads of di erent base stations (BSs) in both the downlink (DL) and uplink (UL) directions of transmission. In presence of such heterogeneity, decoupled UL-DL user association (DUDe), which allows users to associate with di erent BSs for UL and DL transmissions, can be used to optimize network performance. Again, in-band full-duplex (FD) communi- cation is considered as a promising technique to improve the spectral e ciency of future multi-tier fth generation (5G) cellular networks. Nonetheless, due to severe UL-to-DL and DL-to-UL interference issues arising due to FD communications, the performance gains of DUDe in FD multi-tier networks are inconspicuous. To this end, this thesis develops a comprehensive framework to analyze the usefulness of DUDe in a full-duplex multi-tier cellular network. We rst formulate a joint UL and DL user association problem (with the provision of decoupled association) that maximizes the sum-rate for UL and DL transmission of all users. Since the formulated problem is a mixed-integer non-linear programming (MINLP) problem, we invoke approxi- mations and binary constraint relaxations to convert the problem into a Geometric Programming (GP) problem that is solved using Karush-Kuhn-Tucker (KKT) opti- mality conditions. Given the centralized nature and complexity of the GP problem, the solution of which serves as the upper bound for any sub-optimal solution, we formulate a distributed two-sided iterative matching game and develop a solution to obtain the solution of the game. In this game, the users and BSs rank one another using preference metrics that are subject to the externalities (i.e., dynamic interfer- ence conditions). The solution of the game is guaranteed to converge and provides Pareto-e cient stable associations. Finally, we derive e cient light-weight versions of the iterative matching solution, i.e., non-iterative matching and sequential UL-DL matching algorithms. The performances of all the solutions are critically evaluated in terms of aggregate UL and DL rates of all users, the number of unassociated users, and the number of coupled/decoupled associations. Simulation results demonstrate the e cacy of the proposed algorithms over the centralized GP solution as well as traditional coupled and decoupled user association schemes. / October 2016

<p>The aim of the study is to understand the level of co-operation between emerging and commercial farmers in a Water User Associations. The effort is expected to inform policy and improve practice in the building of new water institutions as government strives to implement IWRM.</p>

Future wireless networks are evolving to become ever more heterogeneous, including small cells such as picocells and femtocells, and direct device-to-device (D2D) communication that bypasses base stations (BSs) altogether to share stored and personalized content. Conventional user association schemes are unsuitable for heterogeneous networks (HetNets), due to the massive disparities in transmit power and capabilities of different BSs. To make the most of the new low-power infrastructure and D2D communication, it is desirable to facilitate and encourage users to be offloaded from the macro BSs. This dissertation characterizes the gain in network performance (e.g., the rate distribution) from offloading users to small cells and the D2D network, and develops efficient user association, resource allocation, and interference management schemes aiming to achieve the performance gain. First, we optimize the load-aware user association in HetNets with single-antenna BSs, which bridges the gap between the optimal solution and a simple small cell biasing approach. We then develop a low-complexity distributed algorithm that converges to a near-optimal solution with a theoretical performance guarantee. Simulation results show that the biasing approach loses surprisingly little with appropriate bias factors, and there is a large rate gain for cell-edge users. This framework is then extended to a joint optimization of user association and resource blanking at the macro BSs – similar to the enhanced intercell interference coordination (eICIC) proposed in the global cellular standards, 3rd Generation Partnership Project (3GPP). Though the joint problem is nominally combinatorial, by allowing users to associate to multiple BSs, the problem becomes convex. We show both theoretically and through simulation that the optimal solution of the relaxed problem still results in a mostly unique association. Simulation shows that resource blanking can further improve the network performance. Next, the above framework with single-antenna transmission is extended to HetNets with BSs equipped with large-antenna arrays and operating in the massive MIMO regime. MIMO techniques enable the option of another interference management: serving users simultaneously by multiple BSs – termed joint transmission (JT). This chapter formulates a unified utility maximization problem to optimize user association with JT and resource blanking, exploring which an efficient dual subgradient based algorithm approaching optimal solutions is developed. Moreover, a simple scheduling scheme is developed to implement near-optimal solutions. We then change direction slightly to develop a flexible and tractable framework for D2D communication in the context of a cellular network. The model is applied to study both shared and orthogonal resource allocation between D2D and cellular networks. Analytical SINR distributions and average rates are derived and applied to maximize the total throughput, under an assumption of interference randomization via time and/or frequency hopping, which can be viewed as an optimized lower bound to other more sophisticated scheduling schemes. Finally, motivated by the benefits of cochannel D2D links, this dissertation investigates interference management for D2D links sharing cellular uplink resources. Showing that the problem of maximizing network throughput while guaranteeing the service of cellular users is non-convex and hence intractable, a distributed approach that is computationally efficient with minimal coordination is proposed instead. The key algorithmic idea is a pricing mechanism, whereby BSs optimize and transmit a signal depending on the interference to D2D links, who then play a best response (i.e., selfishly) to this signal. Numerical results show that our algorithms converge quickly, have low overhead, and achieve a significant throughput gain, while maintaining the quality of cellular links at a predefined service level. / text

<p>The aim of the study is to understand the level of co-operation between emerging and commercial farmers in a Water User Associations. The effort is expected to inform policy and improve practice in the building of new water institutions as government strives to implement IWRM.</p>

Aujourd'hui, l'extension des exigences du trafic de données sans fil dépasse le taux de croissance de la capacité des nouvelles technologies d'accès sans fil. Par conséquent, les réseaux sans fil mobiles de la future génération proposent des architectures hétérogènes, généralement appelées réseaux sans fil hétérogènes (HWN). HWN se caractérisent par l'intégration des réseaux cellulaires et des réseaux locaux sans fil (WLAN) pour répondre aux besoins des utilisateurs et améliorer la capacité du système. En fait, l'intégration de différents types de technologies d'accès sans fil dans HWN offre des choix flexibles pour que les utilisateurs soient associés au réseau qui répond le mieux à leurs besoins. Dans ce contexte, cette thèse traite le problème d'association d'utilisateurs et le problème d'allocation de ressources dans un système sans fil hétérogène basé sur des points d'accès Wi-Fi intégrés et des stations de base L TE. Les contributions de cette thèse pourraient être divisées en trois parties principales. Dans la première partie, un nouveau problème d'association d'utilisateurs et d'optimisation de l'allocation des ressources est formulé pour maximiser la satisfaction globale des utilisateurs dans le système. La satisfaction de l'utilisateur est basée sur une fonction de profit pondérée qui vise à améliorer la puissance relative du signal reçu et la diminution de la consommation d'énergie des terminaux mobiles (MT). Étant donné qu'un MT n'est autorisé à être associé qu'à un seul réseau à la fois, le problème d'optimisation formulé est binaire avec une complexité NP complète. Ensuite, plusieurs solutions centralisées avec une complexité à temps polynomial sont proposées pour résoudre le problème formulé. Les solutions proposées sont basées sur des approches heuristiques et sur la relaxation continue du problème d'optimisation binaire formulé. La deuxième partie de la thèse vise à fournir une solution distribuée pour le problème formulé. La solution distribuée proposée déploie la technique de détente lagrangienne pour convertir le problème global formulé en plusieurs problèmes de Knapsack distribués, chaque réseau traite son problème Knapsack correspondant. La méthode de sous gradient est utilisée pour trouver les multiplicateurs lagrangiens optimaux ou sous optimaux. Enfin, la troisième partie de la thèse étudie de nouvelles perspectives de la formulation du problème d'optimisation et ses solutions centralisées et distribuées correspondantes. Un problème d'association d'utilisateurs et d'allocation de ressources basé sur la priorité est formulé. Le problème est ensuite réduit en plusieurs problèmes résolus à l'aide des solutions proposées réparties et centralisées. En outre, une nouvelle solution de maximisation de l'efficacité énergétique est proposée en modifiant les objectifs du problème d'optimisation originalement formulé. / It is indicated that the expansion of the wireless data traffic requirements exceeds the capacity growth rate of new wireless access technologies. Therefore, next-generation mobile wireless networks are moving toward heterogeneous architectures usually referred to as heterogeneous wireless networks (HWNs). HWNs are usually characterized by the integration of cellular networks and wireless local area networks (WLANs) to meet user requirements and enhance system capacity. In fact, integrating different types of wireless access technologies in HWNs provides flexible choices for users to be associated with the network that best satisfies their needs. In this context, this thesis discusses the user association and downlink resource allocation problem in a heterogeneous wireless system that is based on integrated Wi-Fi access points (APs) and long-term evolution (L TE) base stations (BSs). The contributions of this thesis could be divided into three main parts. In the first part, a novel user association and resource allocation optimization problem is formulated to maximize the overall user satisfaction in the system. The user satisfaction is based on a weighted profit function that aims at enhancing the relative received signal strength and decreasing the power consumption of mobile terminals (MTs). Since a MT is only allowed to be associated with a single network at a time, the formulated optimization problem is binary with an NP-complete complexity. Then, multiple centralized solutions with polynomial-time complexities are proposed to solve the formulated problem. The proposed centralized solutions are based on heuristic approaches and on the continuous re laxation of the formulated binary optimization problem. The second part of the thesis aims at providing a distributed solution for the formulated problem. The proposed distributed solution deploys the Lagrangian relaxation .technique in order to convert the global formulated problem into multiple distributed Knapsack problems each network processes its corresponding Knapsack problem. The sub-gradient method is used in order to find the optimal, or near optimal, Lagrangian multipliers. Finally, the third part of the thesis studies new perspectives of the formulated optimization problem and its corresponding centralized and distributed solutions. Mainly, a generalized priority-aware user association and resource allocation problem is formulated. The priority-aware problem is then reduced into multiple problems that are solved using the proposed centralized and distributed solutions. Moreover, a novel power efficiency maximization solution is proposed by altering the objectives of the main formulated optimization problem.

Magister Philosophiae (Integrated Water Resource Management) - MPhl(IWM) / The aim of the study is to understand the level of co-operation between emerging and commercial farmers in a Water User Associations. The effort is expected to inform policy and improve practice in the building of new water institutions as government strives to implement IWRM. / South Africa

La thèse porte sur l'analyse de l'action publique dans le domaine de l'eau d'irrigation au Maroc. Nous analysons la rencontre entre un projet étatique d'aménagement, et un territoire rural au Maroc, à travers les configurations des acteurs et les enjeux locaux de ses composantes sociales et politiques. Comment le projet d'irrigation a-t-il permis d'accélérer une reconfiguration des rapports de pouvoirs et du leadership local, que nous avons analysé à travers les logiques des différents acteurs. Nous avons adopté un cadre analytique emprunté à la sociologie politique et basé sur l'analyse de l'action publique dans le domaine de l'irrigation. Ce cadre analytique nous a permis de mobiliser en parallèle deux modèles d'analyse : 1) le modèle synoptique pour l'analyse d'une action publique monopolisée par les acteurs publics, 2) celui des ajustements mutuels pour l'analyse d'une multitude d'acteurs dans une situation où l'Etat n'a plus le monopole de l'action publique. Nous avons fais le choix méthodologique d'analyser les acteurs en action, en privilégiant un travail empirique basé sur l'analyse des pratiques, et en décryptant une généalogie fine du projet d'irrigation du Moyen Sebou au Maroc. C'est une zone aménagée par les pouvoirs publics dans une perspective de gestion centralisée par l'administration agricole. Les négociations avec le bailleur de fonds, surgies lors du débat international sur la Gestion Participative en Irrigation, ont amené l'administration à confier la gestion de l'irrigation après aménagement à des agriculteurs organisés en associations. / The subject of this thesis is the analysis of public action in the field of irrigation water in Morocco. We analyze the confrontation of a state-led irrigation project, and a rural territory in the North of Morocco, by looking at the configuration and interaction of actors and local issues of its social and political components. How did the irrigation project contribute to the acceleration of a reconfiguration of power relations and local leadership in the area? Our analysis examined this question through the logic of the different actors. We worked within an analytical framework borrowed from political sociology and based on the analysis of state action in the field of irrigation. This analytical framework allowed us to identify two parallel models of analysis: 1) the synoptic model for the analysis of public action monopolized by public actors, 2) the mutual adjustments for the analysis of a multitude of actors in a situation where the state no longer has the monopoly of public action. We have made the methodological choice of analyzing the actors in action, focusing on empirical work based on the analysis of practices, and by decrypting a fine genealogy of the Moyen Sebou scheme in Morocco. The area is managed by public authorities in the context of a state-centralized management of the agricultural administration. Negotiations with the financial donors, that took place during the international debate on ‘Participative Irrigation Management', led the public administration to entrust the management of irrigation to farmers who are active in associations.

Cette recherche porte sur la place des petits périmètres irrigués (PPI) dans le système national de gestion de l’eau en Afrique du Sud. Nous avons choisi une approche par les représentations pour étudier et expliquer les difficultés rencontrées au sein des PPI par la création des water user associations (WUA) prévues par la réforme sur l’eau de 1998. Cette étude mène en parallèle un travail de déconstruction de la politique publique sud-africaine et un travail d’exploration des représentations sociales de petits agriculteurs. L’analyse des interprétations et des choix réalisés par les politiques dans la définition et la mise en place des WUA met en évidence une négation progressive de la capacité de participation des PPI par le biais de révisions successives du modèle de WUA. L’étude des représentations des agriculteurs est menée à l’aide d’un protocole de recherche novateur combinant méthodes discursives et visuelles. Elle révèle des représentations de la gestion de l’eau dépersonnalisées et dissociées du concept de contrôle. La notion de contrôle, centrale au discours des politiques, cristallise les problèmes rencontrés dans la participation des PPI au système national de gestion de l’eau : elle est la marque d’une divergence de représentations entre politiques et agriculteurs et la marque de la marginalisation des PPI. Notre recherche conclut en proposant de redéfinir le rôle des comités d’irrigation existants au sein des PPI mais oubliés de la réforme sur l’eau. Elle propose d’en faire des sous-comités des WUA à la fois indépendants et intégrés, des catalyseurs de la participation des PPI, et des intermédiaires entre agriculteurs et politique nationale de gestion de l’eau. / This research examines the role of small irrigation schemes (SIS) in the South African water management system. We chose to study and interpret the difficulties surrounding the creation of water user associations (WUA), undertaken following the 1998 water reform, in SIS, using a representational approach. This research consists both of a deconstruction of the South African water management policy and an exploration of farmers’ social representations using three case studies. Analysing the interpretations and choices made by officials in the definition and implementation of WUA, the study shows repeated revisions of the institution’s design leading to a gradual exclusion of SIS from participation and undermining of their capacities to contribute meaningfully to the national water management system. The study of farmers’ social representations is conducted using an innovative research design combining discursive and visual methods. It shows depersonalized representations of water management isolated from the concept of control. This concept, central to the political discourse, is at the very core of the difficulties surrounding SIS participation in the national water management system: it symbolizes the discrepancies between farmers’ and officials’ representations and the marginalisation of SIS. Our research concludes by proposing a redefinition of the role of existing irrigation committees in SIS neglected by the water reform until now. It proposes to transform irrigation committees into sub-committees of the WUA, to make them both independent and integrated, to allow them to drive SIS participation, and to establish them as intermediaries between farmers and the national water management policy.

Dans les réseaux d'accès sans fil, l'un des défis les plus récents est la réduction de la consommation d'énergie du réseau, tout en préservant la qualité de service perçue par les utilisateurs finaux. Cette thèse propose des solutions à ce problème difficile considérant deux objectifs, l'économie d'énergie et la minimisation du délai de transmission. Comme ces objectifs sont contradictoires, un compromis devient inévitable. Par conséquent, nous formulons un problème d’optimisation multi-objectif dont le but est la minimisation conjointe de la puissance consommée et du délai de transmission dans les réseaux sans-fil. La minimisation de la puissance est réalisée en ajustant le mode de fonctionnement des stations de base (BS) du réseau d’un niveau élevé de puissance d’émission vers un niveau d'émission plus faible ou même en mode veille. La minimisation du délai de transmission est réalisée par le meilleur rattachement des utilisateurs avec les BS du réseau. Nous couvrons deux réseaux sans-fil différents en raison de leur pertinence : les réseaux locaux sans-fil (IEEE 802.11 WLAN) et les réseaux cellulaires dotés de la technologie LTE. / In wireless access networks, one of the most recent challenges is reducing the power consumption of the network, while preserving the quality of service perceived by the end users. The present thesis provides solutions to this challenging problem considering two objectives, namely, saving power and minimizing the transmission delay. Since these objectives are conflicting, a tradeoff becomes inevitable. Therefore, we formulate a multi-objective optimization problem with aims of minimizing the network power consumption and transmission delay. Power saving is achieved by adjusting the operation mode of the network Base Stations (BSs) from high transmit power levels to low transmit levels or even sleep mode. Minimizing the transmission delay is achieved by selecting the best user association with the network BSs. We cover two different wireless networks, namely IEEE 802.11 wireless local area networks and LTE cellular networks.