A Heuristic Algorithm for a Prize-Collecting Local Access Network Design Problem

Abstract

This paper presents the main findings when approaching an optimization problem proposed to us by a telecommunication company in Austria. It concerns deploying a broadband telecommunications system that lays optical fiber cable from a central office to a number of end-customers, i.e., fiber to the home technology. End-customers represent buildings with apartments and/or offices. It is a capacitated network design problem that requires an installation of optical fiber cables with sufficient capacity to carry the traffic from the central office to the end-customers at minimum cost. This type of problem arises in the design of a Local Access Network (LAN) and in the literature is also named Single-Source Network Loading. In the situation motivating our work the network does not necessarily need to connect all customers (or at least not with the best available technology). Instead, some nodes are potential customers. The aim is to select the customers to be connected to the central server and to choose the cable capacities to establish these connections. The telecom company takes the strategic decision of fixing a percentage of customers that should be served, and aims for minimizing the total cost of the network proving this minimum service. For that reason the underlying problem is called the Prize-Collecting LAN problem (PC-LAN). We propose a sophisticated heuristic to solve real-world instances with up to 86000 nodes and around 1500 potential customers.