Andalucía assesses the investment needed to deploy a fiber-optic network

The setup of fiber-optic telecommunication networks involves high investment efforts. The Regional Government of Andalusia assigned us the development of a tool capable of evaluating the deployment cost of a network that was not to be limited only to connecting large cities, but also to include smaller towns, in order to prevent them from staying behind the progress of the Information Society. The Andalusian regional Government aimed to deploy a network capable of accessing most of the municipalities in the region, even those municipalities that could not be profitable from a monetary perspective. We developed a nonlinear mathematical programming model with special focus on the investment costs. The costs included the parts corresponding to the civil-engineering works, as well as those related to the telematic link deployment. The solution of such a complex problem was found by a genetic algorithm, which was previously tested with a set of trial problems. The results were used to persuade private companies to expand their fiber-optic networks to reach small towns

Optimisation of connections to a fibre network

Stronger competition together with the development of new technologies have forced the Telecom Service Providers (TSP's) in the Netherlands to look for sophisticated optimisation methods to reduce the costs of their communication services especially for new areas such as the application of fibre technology.Fibre is being considered as the transmission medium of the future because fibre deadens the signals much less than the traditional media such as copper and coax, a lot of data can be transmitted at the same time and there are only a few failures. Another advantage is that fibre cables are thin and light so that they can be put into the ground rather easily.This article describes optimisation models with the objective to minimise the costs of constructing and managing a fibre network.The optimisation models have been developed to support decisions about the design and use of a fibre network and are based on the practical situation at Enertel being one of the new TSP’s. For Enertel a national backbone was already realised. The main problem to be solved concerned the optimisation of the access to the fibre network.

Optimisation of connections to a fibre network

Stronger competition together with the development of new technologies have forced the Telecom Service Providers (TSP's) in the Netherlands to look for sophisticated optimisation methods to reduce the costs of their communication services especially for new areas such as the application of fibre technology. Fibre is being considered as the transmission medium of the future because fibre deadens the signals much less than the traditional media such as copper and coax, a lot of data can be transmitted at the same time and there are only a few failures. Another advantage is that fibre cables are thin and light so that they can be put into the ground rather easily. This article describes optimisation models with the objective to minimise the costs of constructing and managing a fibre network. The optimisation models have been developed to support decisions about the design and use of a fibre network and are based on the practical situation at Enertel being one of the new TSP’s. For Enertel a national backbone was already realised. The main problem to be solved concerned the optimisation of the access to the fibre network

Multicommodity capacitated network design

Network design models have wide applications in telecommunications and transportation planning; see, for example, the survey articles by Magnanti and Wong (1984), Minoux (1989), Chapter 16 of the book by Ahuja, Magnanti and Orlin (1993), Section 13 of Ahuja et al. (1995). In particular, Gavish (1991) and Balakrishnan et al. (1991) present reviews of important applications in telecommunications. In many of these applications, it is required to send flows (which may be fractional) to satisfy demands given arcs with existing capacities, or to install, in discrete amounts, additional facilities with fixed capacities. In doing so, one pays a price not only for routing flows, but also for using an arc or installing additional facilities. The objective is then to determine the optimal amounts of flows to be routed and the facilities to be installed. Document type: Part of book or chapter of boo

Satellite Network, Design, Optimization, and Management

We introduce several network design and planning problems that arise in the context of commercial satellite networks. At the heart of most of these problems we deal with a traffic routing problem over an extended planning horizon. In satellite networks route changes are associated with significant monetary penalties that are usually in the form of discounts (up to 40%) offered by the satellite provider to the customer that is affected. The notion of these rerouting penalties requires the network planners to consider management problems over multiple time periods and introduces novel challenges that have not been considered previously in the literature. Specifically, we introduce a multiperiod traffic routing problem and a multiperiod network design problem that incorporate rerouting penalties. For both of these problems we present novel path-based reformulations and develop branch-and-price-and-cut approaches to solve them. The pricing problems in both cases present new challenges and we develop special purpose approaches that can deal with them. We also show how these results can be extended to deal with traffic routing and network design decisions in other settings with much more general rerouting penalties. Our computational work demonstrates the benefits of using the branch-and-price-and-cut procedure developed that can deal with the multiperiod nature of the problem as opposed to straightforward, myopic period-by-period optimization approaches. In order to deal with cases in which future demand is not known with certainty we present the stochastic version of the multiperiod traffic routing problem and formulate it as a stochastic multistage recourse problem with integer variables at all stages. We demonstrate how an appropriate path-based reformulation and an associated branch-and-price-and-cut approach can solve this problem and other more general multistage stochastic integer multicommodity flow problems. Finally, we motivate the notion of reload costs that refer to variable (i.e., per unit of flow) costs for the usage of pairs of edges, as opposed to single edges. We highlight the practical and theoretical significance of these cost structures and present two extended graphs that allow us to easily capture these costs and generate strong formulations

Komputerowe narzędzia do wspomagania decyzji w sektorze telekomunikacyjnym. Telekomunikacja i Techniki Informacyjne, 2000, nr 3-4

Dokonano przeglądu zastosowań systemów wspomagania decyzji w sektorze telekomunikacyjnym. Przedstawiono najbardziej reprezentatywne przykłady wykorzystania narzędzi komputerowych do wspomagania procesów decyzyjnych: hurtownie danych, analizę finansową i modelowanie matematyczne. Wskazano też perspektywy wspomagania decyzji w zarządzaniu strategicznym na przykładzie negocjacji umów, dotyczących połączeń międzyoperatorskich

Matheuristics:survey and synthesis

In integer programming and combinatorial optimisation, people use the term matheuristics to refer to methods that are heuristic in nature, but draw on concepts from the literature on exact methods. We survey the literature on this topic, with a particular emphasis on matheuristics that yield both primal and dual bounds (i.e., upper and lower bounds in the case of a minimisation problem). We also make some comments about possible future developments

Capacity expansion in contemporary telecommunication networks

Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2007.Includes bibliographical references (p. 155-160).We study three capacity expansion problems in contemporary long distance telecommunication networks. The first two problems, motivated by a major long distance provider, address capacity expansion in national hybrid long distance telecommunication networks that use both the traditional TDM technology and more recent VoIP technology to transport voice calls. While network capacity expansion in general is known to be hard to approximate, we exploit the unique requirements associated with hybrid networks to develop compact models and algorithms with strong performance guarantees for these problems. For a single period single facility capacity expansion problem in a hybrid network, using a decomposition approach we design a (2 + E)-factor approximation algorithm. Generalizing this idea, we propose a Decentralized Routing Scheme that can be used to design approximation algorithms for many variations of hybrid network capacity expansion. For the Survivable Capacity Expansion Problem in hybrid networks, in which we are required to install enough capacity to be able to support all demands even if a single link fails, we propose a compact integer program model. We show that this problem is APX-Hard, and present two heuristics with constant worst case performance guarantees. Finally, we consider the capacity planning problem when peak demands occurring at different times can share network capacity. We propose a general model for capturing time variation of demand, and establish a necessary and sufficient condition for a capacity plan to be feasible. Using a cutting plane approach, we develop a heuristic procedure. Computational experiments on real and random instances show that the proposed procedure performs well, producing solutions within 12% of optimality on average for the instances tested. The tests also highlight the significant savings potential that might be obtained by capacity planning with time sharing.by Raghavendran Sivaraman.Ph.D

Decomposition methods for large-scale network expansion problems

Network expansion problems are a special class of multi-period network design problems in which arcs can be opened gradually in different time periods but can never be closed. Motivated by practical applications, we focus on cases where demand between origin-destination pairs expands over a discrete time horizon. Arc opening decisions are taken in every period, and once an arc is opened it can be used throughout the remaining horizon to route several commodities. Our model captures a key timing trade-off: the earlier an arc is opened, the more periods it can be used for, but its fixed cost is higher, since it accounts not only for construction but also for maintenance over the remaining horizon. An overview of practical applications indicates that this trade-off is relevant in various settings. For the capacitated variant, we develop an arc-based Lagrange relaxation, combined with local improvement heuristics. For uncapacitated problems, we develop four Benders decompositi