Simultaneous optimization of network structure and circuit routing in transmission networks

Abstract

A telecommunications network can be separated into a switching and a transmission network. Using the idea of this separation, the planning and optimization of telecommunication networks is divided into two distinct but interlinked stages as the switching network optimization and the transmission network optimization. Furthermore, a modular approach is chosen to solve these sub-problems. In this study, the first two modules of the transmission network optimization problem, namely, the network structure and circuit routing optimization modules, will be handled. Unlike the algorithms contained in literature, a simultaneous optimization procedure is adopted in this study. The developed solution procedure considers this problem both as a development (no existing transmission media) and as a capacity expansion (taking account of the existing network) problem. One of the most important features of this problem is the existence of economies of scale in the link cost functions for installing transmission systems. These link cost functions can be decomposed into a fixed and a variable cost component. In the case of using alternate systems, these functions become piecewise concave, that is, concave in the range covered by any single technology. Some of the major characteristics of the developed algorithm are as follows: it can take into account the existing network, consider mixed technology and alternate transmission systems, handle economies of scale and fixed charges present in the problem, together with the capacity limits and the parallel links in the network.