Willem Vereecken

Worldwide energy needs for ICT: The rise of power-aware networking

As Information and Communication Technology (ICT) is becoming more and more wide-spread and pervasive in our daily life, it is important to get a realistic overview of the worldwide impact of ICT on the environment in general and on energy and electricity needs in particular. This paper reports on a detailed study to estimate this impact today and to predict how this will evolve in the future. From this survey, important conclusions for the future of ICT industry and the Internet will be drawn, and challenges and research directives will be deduced.

Power consumption in telecommunication networks: overview and reduction strategies

One of the main challenges for the future of information and communication technologies is reduction of the power consumption in telecommunication networks. The key consumers are the home gateways at the customer premises for fixed line access technologies and the base stations for wireless access technologies. However, with increasing bit rates, the share of the core networks could become significant as well. In this article we characterize the power consumption in the different types of networks and discuss strategies to reduce the power consumption.

Power consumption modeling in optical multilayer networks

The evaluation of and reduction in energy consumption of backbone telecommunication networks has been a popular subject of academic research for the last decade. A critical parameter in these studies is the power consumption of the individual network devices. It appears that across different studies, a wide range of power values for similar equipment is used. This is a result of the scattered and limited availability of power values for optical multilayer network equipment. We propose reference power consumption values for Internet protocol/multiprotocol label switching, Ethernet, optical transport networking and wavelength division multiplexing equipment. In addition we present a simplified analytical power consumption model that can be used for large networks where simulation is computationally expensive or unfeasible. For illustration and evaluation purpose, we apply both calculation approaches to a case study, which includes an optical bypass scenario. Our results show that the analytical model approximates the simulation result to over 90% or higher and that optical bypass potentially can save up to 50% of power over a non-bypass scenario.

Worldwide electricity consumption of communication networks

There is a growing research interest in improving the energy efficiency of communication networks. In order to assess the impact of introducing new energy efficient technologies, an up-to-date estimate for the global electricity consumption in communication networks is needed. In this paper we consider the use phase electricity consumption of telecom operator networks, office networks and customer premises equipment. Our results show that the network electricity consumption is growing fast, at a rate of 10 % per year, and its relative contribution to the total worldwide electricity consumption has increased from 1.3% in 2007 to 1.8% in 2012. We estimate the worldwide electricity consumption of communication networks will exceed 350 TWh in 2012.

Overall ICT footprint and green communication technologies

Green communication technologies currently receive a lot of attention. In this paper we give an overview of the environmental issues related to communication technologies en present an estimation of the overall ICT footprint. Additionally we present some approaches on how to reduce this footprint and how ICT can assist in other sectors reducing their footprint.

Energy-efficiency in telecommunications networks: Link-by-link versus end-to-end grooming

The large share of energy consumption in telecommunication networks is expected to shift from access networks to core networks. Estimating the power consumption of core networks is not easy, as they vary a lot in size and topology. Using an exemplary but realistic core network, we estimate its power consumption for both a link-by-link grooming and an optical end-to-end grooming scenario. We show that optical end-to-end grooming consumes about half the power of the alternative scenario.

Comparison of power consumption of mobile WiMAX, HSPA and LTE access networks

Nowadays, wireless access networks are a large contributor to the CO2 emissions of ICT. Today, ICT is responsible for 4 % of the annual energy consumption and this number is expected to grow drastically in the coming years. The power consumption of these wireless access networks will thus become an important issue in the coming years. In this paper, the power consumption of wireless base stations for mobile WiMAX, HSPA and LTE is modelled and compared for a future scenario. For our research, we assume a suburban area and a physical bit rate of 10 Mbps. We compare the wireless technologies for a SISO and three MIMO systems. For each case, we give a ranking of the wireless technologies as a function of their power consumption, range and energy eff ciency. Based on these results, we cover a specif ed area with each technology and determine which technology is the best solution for the specif ed area. We also compare the power consumption of the wireless access networks with the power consumption of the wired access networks.

Power consumption in wireless access network

The power consumption of wireless access networks will become an important issue in the coming years. In this paper the power consumption of base stations for mobile WiMAX, fixed WiMAX and UMTS is modelled. This power consumption is evaluated in relation to the coverage. For a physical bit rate of 2 Mbps, a power consumption of approximately 5600 W and a range of 1 km is obtained with UMTS. Fixed WiMAX covers 70 % and mobile WiMAX only 40 % of this range. However, fixed and mobile WiMAX consume roughly 50 % less than UMTS. In a suburban area and for a physical bitrate of 2 Mbps, fixed WiMAX base stations consume approximately 6 W per user, mobile WiMAX base stations 17 W per user, and UMTS base stations 5 W per user. The power consumption of these wireless access networks is compared with other access network technologies and research challenges concerning these access networks are presented.

Reducing the Power Consumption in Wireless Access Networks: Overview and Recommendations

Due to growing importance of wireless access and the steeply growing data volumes being transported, the power consumption of wireless access networks will become an important issue in the coming years. This paper presents a model for this power consumption and investigates three base station types: macrocell, microcell, and femtocell base stations. Based on these models, the coverage effectiveness of the three base station types is compared and the influence of some power reducing techniques such as sleep modes and MIMO (Multiple Input Multiple Output) is evaluated.

Power reduction techniques in multilayer traffic engineering

Automatically switched multilayer IP-over-optical networks offer extensive flexibility in coping with offered traffic. Multilayer traffic engineering (MLTE) takes advantage of this through online IP logical topology reconfiguration in addition to the more traditional rerouting. Although MLTE typically optimizes towards resource usage, bandwidth throughput and QoS performance, energy efficiency has become an equally important objective recently. In this paper, we examine two types of power reduction techniques and their interaction with the MLTE scheme: simple down-scaling of equipment power requirements, or more radical equipment architecture innovations which concentrate on reducing idle energy consumption. We show that both techniques require a different MLTE approach, and compare total power requirements for both scenarios.