Fiber optical network design problems : case for Turkey

Abstract

The problems within scope of this thesis are based on an application arising from one of the largest Internet service providers operating in Turkey. There are mainly two different problems: the green field design and copper field re-design. In the green field design problem, the aim is to design a least cost fiber optical network from scratch that will provide high bandwidth Internet access from a given central station to a set of aggregated demand nodes. Such an access can be provided either directly by installing fibers or indirectly by utilizing passive splitters. Insertion loss, bandwidth level and distance limitations should simultaneously be considered in order to provide a least cost design to enable the required service level. On the other hand, in the re-design of the copper field application, the aim is to improve the current service level by augmenting the network through fiber optical wires. Copper rings in the existing infrastructure are augmented with cabinets and direct fiber links from cabinets to demand nodes provide the required coverage to distant nodes. Mathematical models are constructed for both problem specifications. Extensive computational results based on real data from Kartal (45 points) and Bakırköy (74 points) districts in Istanbul show that the proposed models are viable exact solution methodologies for moderate dimensions.