Wireless networks increasingly utilize diverse spectral bands, which exhibit vast differences in transmission range, bandwidth and available airtime. While tremendous efforts have been devoted to enable efficient mobile access of single-band networks and increase their throughput, e.g., via network coding, such single-band solutions are unfortunately oblivious to the diversity and abundance of the available spectral bands. In this thesis, I present and evaluate novel schemes for mobile access and for throughput increase using network coding, schemes that are designed for diverse-band wireless networks, i.e., networks operating in multiple diverse bands. Specifically, I introduce the first scheme designed for mobile clients to evaluate and select both APs and spectral bands in diverse-band networks. The fundamental problem is that the potentially vast number of spectrum and AP options may render scanning prohibitive. Thus, my key technique is for clients to infer the critical metrics of channel quality and available airtime for their current location and bands using limited measurements collected in other bands and at other locations. I evaluate my scheme via experiments and emulations, which are enabled by a four-band testbed that I deploy. A key finding is that under a diverse set of operating conditions, mobile clients can accurately predict their performance without a direct measurement at their current location and spectral bands. Moreover, I introduce the first band selection schemes designed for diverse-band networks exploiting overheard packets to enable network coding. The main problem is that band selections in such networks are challenged by conflicting factors affecting throughput: while the number of overhearing nodes generally increases with decreasing frequency, channel width and spatial reuse unfortunately decrease. Thus, the key technique of the proposed schemes is to jointly incorporate coding gains, channel width and spatial reuse in band selections. I evaluate these schemes via simulations employing a physical-layer model driven by measurements collected using the deployed four-band testbed. An important finding is that the proposed schemes can outperform coding-oblivious spectrum access in terms of throughput, as their band selection enables more coding opportunities. My work has two key implications. First, it can significantly improve throughput performance in networks enabled by today’s unlicensed spectrum and by the billion-dollar industry of white-space networking. Second, I anticipate that this thesis will highly impact future research, as I open new research areas in a domain that has attracted such tremendous commercial and research interest.

Dans cette thèse, on s'intéresse à deux problèmes de conception de réseaux, utilisant la technologie OFDM multi-bandes. Le premier problème concerne la conception d'un réseau mono-couche avec contraintes spécifiques. Nous donnons une formulation en PLNE pour ce problème et étudions le polyèdre associé à sa restriction sur un arc. Nous introduisons deux familles d'inégalités valides définissant des facettes et développons un algorithme de coupes et branchements pour le problème. Nous étudions la variante multicouche du problème précédent et proposons plusieurs PLNE pour le modéliser. Nous identifions plusieurs familles de facettes et discutons des problèmes de séparation associés. Nous développons un algorithme de coupes et branchements utilisant l'ensemble des contraintes identifiées. Enfin, une formulation compacte et deux formulations basées sur des chemins sont proposées pour le problème. Nous présentons deux algorithmes de génération de colonnes et branchements pour le problème. / In this thesis we consider two capacitated network design (CND) problems, using OFDM multi-band technology. The first problem is related to single-layer network design with specific requirements. We give an ILP formulation for this problem and study the polyhedra associated with its arc-set restriction. We describe two families of facet defining inequalities. We devise a Branch-and-Cut algorithm for the problem. Next, we investigate the multilayer version of CND using OFDM technology. We propose several ILP formulations and study the polyhedron associated with the first (cut) formulation. We identify several classes of facets and discuss the related separation problem. We devise a Branch-and-Cut algorithm embedding valid inequalities of both single-layer and multilayer problems. The second formulation is compact, and holds a polynomial number of constraints and variables. Two further path formulations are given which yield two efficient Branch-and-Price algorithms for the problem.