In the last decade, cellular networks have been characterized by an ever-growing user data demand. This caused increasing capacity shortfall and coverage issues, aggravated by inefficient fixed spectrum management policies and obsolete network structures. From a practical point of view, novel technical and architectural solutions have been proposed to frame next generation cellular networks, capable of meeting the identified target performance to satisfy the user data demands. Specifically, new spectrum management policies based on the so-called dynamic spectrum access (DSA), together with hierarchical approaches to network planning, where a tier of macro base stations is underlaid with a tier of massively deployed low-power small base stations, are seen as promising candidates to achieve this scope. The resulting two-tiered network layout may improve the capacity of current networks in several ways, thanks to a better average link quality between the devices, a more efficient usage of spectrum resources and a potentially higher spatial reuse. In this thesis, we focus on the challenging problem arising when the two tiers share the transmit band, to capitalize on the available spectrum and avoid possible inefficiencies. In this case, the coexistence of the two tiers is not feasible, if suitable interference management techniques are not designed to mitigate/cancel the mutual interference generated by the active transmitters in the network. This thesis is divided in three main parts, and proposes a rather exhaustive approach to the development of new DSA and interference management techniques, to go from the theoretical basis up to a proof-of-concept development.

Au cours de la dernière décennie, les réseaux cellulaires ont connu une augmentation exponentielle de la demande de données. En conséquence, nous constatons des chutes de capacités occasionnelles et des problèmes de couverture, aggravés par des politiques de gestion du spectre inefficaces et des structures réseaux obsolètes. Le développement de nouvelles politiques pour le management du spectre, telles que les schémas de dynamic spectrum access (DSA), permettra, avec le déploiement de réseaux multi-niveaux, de traiter les problèmes précédemment évoqués et encadrer les réseaux mobiles de prochaine génération. Un réseau ainsi conçu pourra augmenter la capacité offerte par les réseaux actuels et atteindre les niveaux de performance requis par les demandes de data des utilisateurs, via une utilisation plus efficace du spectre disponible et une meilleure réutilisation spatiale. Dans cette thèse, nous nous concentrons principalement sur le problème inhérent au fait de posséder deux niveaux de transmission au sein de notre réseau (mini et macro stations de base) qui doivent dès lors se partager une bande commune, capitaliser sur le spectre disponible et éviter les situations d’interférences où elles s’annihilent mutuellement. Dans ce cas, la question de la coexistence se pose et elle ne peut être atteinte que si des techniques de management d’interférence sont développées pour mitiger/annuler l’interférence générée par ces deux transmetteurs. Le travail se décompose en trois parties et propose une approche plutôt exhaustive pour le développement de nouvelles techniques de DSA et gestion de l'interférence, d’un niveau purement théoriques aux premières trames de preuve de concept. / In the last decade, cellular networks have been characterized by an ever-growing user data demand. This caused increasing capacity shortfall and coverage issues, aggravated by inefficient fixed spectrum management policies and obsolete network structures. From a practical point of view, novel technical and architectural solutions have been proposed to frame next generation cellular networks, capable of meeting the identified target performance to satisfy the user data demands. Specifically, new spectrum management policies based on the so-called dynamic spectrum access (DSA), together with hierarchical approaches to network planning, where a tier of macro base stations is underlaid with a tier of massively deployed low-power small base stations, are seen as promising candidates to achieve this scope. The resulting two-tiered network layout may improve the capacity of current networks in several ways, thanks to a better average link quality between the devices, a more efficient usage of spectrum resources and a potentially higher spatial reuse. In this thesis, we focus on the challenging problem arising when the two tiers share the transmit band, to capitalize on the available spectrum and avoid possible inefficiencies. In this case, the coexistence of the two tiers is not feasible, if suitable interference management techniques are not designed to mitigate/cancel the mutual interference generated by the active transmitters in the network. This thesis is divided in three main parts, and proposes a rather exhaustive approach to the development of new DSA and interference management techniques, to go from the theoretical basis up to a proof-of-concept development.