Energy efficiency in wired telecommunication networks: approaches, methodologies and results

This PhD thesis describes the research activities carried out with the Department of Electronics and Telecommunications of Politecnico di Torino. Most of the research activities have been developed inside the European project TREND (Towards Real Energy-efficient Network Design), a Network of Excellence financed by the European Union. In particular, collaborations have been conducted with Orange Labs, Networks and Carriers, of Lannion (France), Technische Universitat Berlin (Germany) and FASTWEB (Italy). The target of this thesis is the improvement of the energy efficiency in wired telecommunication networks. Indeed, several research studies have underlined that the already huge energy consumption is destined to increase in the next years since the traffic in telecommunication networks will continue to grow constantly due to the increasing popularity of new bandwidth-consuming applications, and the increase of population using them. This situation thus urges to find strategies that can mitigate the demand of energy in the networks. The aim of the thesis is indeed to propose energy-aware strategies, that can improve the energy efficiency in the networks, and to evaluate which could be the real benefits of introducing these strategies. In particular, during the three years of research, proposals dedicated to the various network segments have been examined. Indeed, studies reported that each network segment is or will be responsible of the critical energy situation of the networks. For instance, the energy consumed in access and aggregation networks represents the largest contribute in the consumption of wired telecommunication networks and no reduction is expected in the future. While, in core networks, the growth of the consumption will be consistent, more than doubling its energy consumption quota in about 10 years. Finally, attention has been devoted also to the performance and economical aspects. Indeed, the improvement of the energy efficiency may affect the performance perceived by the users and also it may require additional investments, which can be compensated by the economical savings obtained by reducing the energy bill.