On facility-network design for broadband communications

Abstract

This thesis is concerned with the topological design of a facility network for broadband communications. In designing the facility network, transmission facilities such as concentrators, multiplexers and digital cross-connect systems are usually introduced to use the communication cable efficiently. In consideration of the fact that the hubbing topology is recommended as one of the economic and attractive structures for broadband communication network, we concentrate the research interest on the design of facility network with hubbing topology. To design such network, three kinds of major cost components are considered: fixed cost of establishing a hub facility, fixed cost of placing conduit and variable cost of installing cables. The tradeoffs between these major costs will be fully accounted for in this thesis. It is, however, such an immensely complicated task to optimally capture the tradeoffs between all these costs. Owing to the serious drawback of the conventional approach of partitioning the whole problem into three subproblems, it is desired to directly deal with the problem in an integrated framework. In this respect, we will develop the unified model to design facility networks with hubbing topology having the minimal total cost, and also develop efficient solution methods. First, we consider the design of facility network for centralized communication systems, which is commonly found in the local access communication networks. By introducing a dummy node and some dummy arcs, we formulated the problem as a variant of classical network design model, allowing the incorporation of the well-known dual-ascent solution strategy. Despite the complexity inherent on the design problem, the performance of the proposed solution heuristic is shown via the extensive computational experiments with large-scale test problems. Second, we deal with the problem for a facility network design of large-scale communication systems with regional restrictions, which is usual...