PhD defense of Alvinice Kodjo

PhD Alvinice Kodjo

  • Title: “Design and Optimization of Wireless Backhaul Networks”
  • When: December 18, 2014 — 14:30
  • Where: Polytech-Nice Sophia Antipolis, salle E+131 (Amphi Gradiné Templiers 2)
  • Committee:
  • Abstract: The main work of this thesis focuses on the wireless backhaul networks. This type of network has the advantage of allowing rapid and easy deployment at relatively low costs while offering capacity of up to 1Gbps over links of a hundred of kilometers. We studied different optimization problems in such networks that represent real challenges for industrial sector.
    The first issue addressed in this thesis concerns the capacity allocation on the links at minimum cost. It was solved by a linear programming approach with column generation. Our method solves the problems on large size networks. In addition, we quickly obtain very good quality solutions.
    We then studied the problem of network infrastructure sharing between virtual operators. The objective is to maximize the revenue of the operator of the physical infrastructure while satisfying the demands (constraints of quality of service) of virtual operators customers of the network. In this context, we proposed a model to the problem using mixed integer linear programming. Our formulation is robust to changes in traffic demands of virtual operators.
    Another operational expenditure in this type of network is the energy consumption. Many operators are now seeking to reduce network energy consumption, both by using more efficient equipments and by using more appropriate routing solutions. We proposed a robust energy-aware routing solution for the network. The proposed model is based on backbone networks, but it can easily be adapted to wireless back- haul networks. Our solution was formulated using a mixed integer linear program. We also proposed heuristics to find efficient solutions for large networks.
    The last work of this thesis focuses on cognitive radio networks and more specifically on the problem of bandwidth sharing. We formalized it using a linear program with a different approach to robust optimization. This model differs from other cases of robust optimization discussed above by the position of the uncertain terms in the model. We based our solution on the 2-stage linear robust formulation proposed by Michel Minoux.
    This thesis was carried out in partnership with the SME 3ROAM ( and in collaboration with various researchers from different universities in the world. It was co-funded by the PACA province and the SME 3ROAM.

  • Keywords: Backhaul networks, Wireless networks, Operations Research, Robust optimization.