Le monde des communications par satellite est dominé par les systèmes de diffusion de la télévision. Cependant, des satellites de communication offrent aussi des services de téléphonie et de données. Ils sont regroupés dans les familles des systèmes fixes et mobiles et ciblent des marchés de niche. Dans cette thèse, nous avons la volonté d’étendre les scénarios d’utilisation de ces systèmes. Notre vision nous dicte que leur développement est lié à l’utilisation de réseaux hybrides mobiles satellite-terrestre. En effet, une utilisation complémentaire des deux segments permet de s’affranchir d’une concurrence trop féroce des réseaux de télécommunications terrestres. Pour cela, nous optons pour deux applications qui nous paraissent prometteuses : un réseau mobile LTE (Long Term Evolution) avec des stations de base qui possèdent un backhaul satellite et un réseau MANET (Mobile Ad-hoc NETwork) qui s’interconnecte à des réseaux extérieurs grâce à des liaisons satellite. Nous soulevons l’un des problèmes les plus contraignants du réseau mobile LTE avec des backhauls satellite : la gestion de la mobilité. L’analyse du standard nous a conduits à conclure quant à la nécessité d’optimiser les procédures du handover. Ceux qui nécessitent des modifications surviennent entre des stations de base qui n’utilisent pas le même backhaul satellite et entre une station de base avec un backhaul satellite vers une avec un backhaul terrestre. Deux points nous ont semblé importants : la phase de préparation et le mécanisme qui permet d’éviter les pertes. Nous proposons donc une nouvelle phase de préparation qui prend en compte le retard induit par la liaison satellite ainsi qu’une phase de préparation à double décision combinée avec une préparation de multiples stations de base. Nous tentons ainsi de maximiser les chances de réaliser un handover avec succès. Puis, nous avons imaginé un mécanisme qui permet à la fois d’éviter les pertes lors de l’exécution du handover et de sauvegarder les précieuses ressources du satellite. Les réseaux MANET associés à des liaisons satellite offrent des caractéristiques très intéressantes pour les communications d’urgence, telles que l’indépendance vis-à-vis des infrastructures terrestres susceptibles d’être endommagées par des catastrophes ainsi qu’un déploiement rapide pour une intervention sur le théâtre des opérations. Nous avons souhaité améliorer l’un des points cruciaux dans le cadre d’une hybridation : la sélection de la passerelle satellite. Nous avons donc développé un mécanisme qui prend en compte la charge sur les passerelles satellite ainsi que le phénomène d’oscillation de passerelle souvent négligé dans la littérature. Ces optimisations ont pour but de favoriser le développement de réseaux hybrides satellite terrestres en améliorant les performances de ces réseaux. L’avenir nous semble prometteur quant à l’utilisation de la technologie LTE avec un backhaul satellite pour lequel nous avons proposé une nouvelle gestion de la mobilité qui est primordiale pour son développement. / Satellite communications are leaded by television broadcasting. Yet, fixed and mobile satellite systems provide voice services as well as IP-based applications. In this thesis, we try to develop user scenarios in order to extend their targeted market. Our vision to reach this objective consists to use hybrid satellite and terrestrial mobile networks. This network design avoids a competition between both segments in which a satellite success is difficult to imagine. Furthermore, hybrid networks may draw benefits from both segments. Two promising scenarios have been selected. The first one consists in a mobile LTE network (Long Term Evolution) with base stations backhauled by satellite links whereas the second scenario is composed of a Mobile Ad-hoc Network (MANET) connected to external networks thanks to satellite systems. One of the main problems in the hybrid LTE scenario is caused by mobility procedures. As a consequence of the standard analysis, we have decided to optimize the mobility management in two cases: a handover between two base stations for which the backhaul is provided by two different satellite terminals and a handover from a base station with a satellite backhaul to one with a terrestrial backhaul. Two procedures have drawn our attention: the preparation phase and the loss avoidance mechanism during the execution phase. First of all, we design a new procedure for the preparation which takes into account the delay induced by the satellite link. This new phase is based on a twofold decision preparation associated with multiple preparations. This solution leads to an increase of handover success. The second optimization aims to avoid losses during the execution phase and, at the same time, save satellite resources. MANET and satellite hybridization leads to very interesting characteristics for public safety communications. Indeed, these networks are independent of terrestrial infrastructures that can be impaired or destroyed. Furthermore, they can be rapidly deployed in the theater of operation. Gateway selection is a crucial problem linked to hybrid MANET. Therefore, we have focused our work on this mechanism taking into account the measured load on the satellite links as well as an oftenneglected phenomenon, the gateway flapping. These optimizations tend to promote hybrid satellite and terrestrial networks improving their performance. A promising future is foreseen for the hybrid LTE technology and we have proposed a solution to a problem that may be very detrimental to its deployment.

Drastic growth and chaotic deployment of Wireless Local Area Networks (WLANs) in dense urban areas are some of the common issues of many Internet Service Providers (ISPs) and Wi-Fi users. These issues result in a substantial reduction of the throughput and impede the balanced distribution of bandwidth among the users. Most of these networks are using unmanaged consumer-grade Access Points (APs) and there is no cooperation among them. Moreover, the conventional association mechanism that selects APs with the strongest Received Signal Strength Indicator (RSSI) aggravates this situation. In spite of all these challenges, there is a great opportunity to build cooperative overlay networks among the APs that are owned by different ISPs, companies or individuals in dense urban areas. In fact, ISPs can distribute the resources among their customers in a cooperative fashion using a shared overlay platform which is constructed on top of the existing infrastructures. This approach helps the ISPs with efficient utilization of their resources and promoting the Quality of their Services (QoS). For instance, cooperative association control among the APs of different ISPs enables them to alleviate the drastic impact of interference in populated areas and improves the network throughput. Indeed, all Wi-Fi customers can associate to the APs from different ISPs and it leads to the construction of a large unified WLAN that expands the network coverage, significantly. Moreover, it results in a notable reduction of deployment costs and enhancement of customer satisfaction. Hence, as one of the key contributions of this dissertation, a cooperative framework for fine-grained AP association in dense WLANs is presented. On top of this framework, a thorough formulation and a heuristic solution to solve the aforementioned problems are introduced. The key enabler of the proposed solution is Software Defined Networking (SDN) which not only gives us an exceptional level of granularity but also empowers us to utilize high-performance computing resources and more sophisticated algorithms. Also, over the past few years, some of the largest cellular operators restricted their unlimited data plans and proposed tiered charging plans enforced by either strict throttling or large overage fees. While cellular operators are trying to guarantee the QoS of their services in a cost-effective and profitable manner, WLANs and Wi-Fi Mesh Networks (WMNs) as viable complements can be used to form a multihop backhaul connection between the access and the core networks. Indeed, the utilization of WMNs provides an opportunity to achieve a high network capacity and wide coverage by the employment of inexpensive commercial off-the-shelf products. Moreover, by bridging the WMNs and cellular networks, and the fine-grained traffic engineering of network flows, it is possible to provide a cost-effective Internet access solution for people who cannot afford the high cost of data plans. However, there are certain requirements in terms of QoS for different services over multi-hop backhaul networks. In addition, the process of service provisioning in WMNs incorporates tightly correlated steps, including AP association, gateway selection, and backhaul routing. In most of the prior studies, these steps were investigated as independent NP-hard problems and no unified formulation that considers all these steps (at different tiers of WMNs) has been presented. Hence, as another contribution of this dissertation, a structured and thorough scheme to address the demands of end-users over SDN-aware WMNs is introduced. In contrast to most of the former work, this scheme takes the key characteristics of wireless networks into account, especially for Multi-Channel Multi-Radio WMNs. The proposed solution can be applied to the large-scale scenarios and finds a near-optimal solution in polynomial time. Furthermore, since the presented solution may split the packets of a single flow among multiple paths for routing and there are non-trivial drawbacks for its implementation, a randomized single-path flow routing for SDN-aware WMNs is introduced. The randomized nature of the introduced solution avoids the complexities of implementing a multi-path flow routing and it presents a viable routing scheme that guarantees certain performance bounds. The functionality and performance of all the presented solutions have been assessed through extensive numerical results and real testbed experimentations as a proof of concept. It is important to note that the solutions presented in this dissertation can be utilized to provide a large variety of services for Wi-Fi users, while they guarantee different QoS metrics. / Graduate