Green Communications

Principles, Concepts and Practice

Konstantinos Samdanis, Peter Rost, Andreas Maeder, Michela Meo, Christos Verikoukis, Konstantinos Samdanis, Peter Rost, Andreas Maeder, Michela Meo, Christos Verikoukis, Konstantinos Samdanis, Christos Verikoukis

• Publisher: Wiley
• Year: 2015
• Print ISBN: 9781118759264
• eBook ISBN: 9781118759233
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Mobile & Wireless Communications
• Index: Technology & Engineering

This book provides a comprehensive view of green communications considering all areas of ICT including wireless and wired networks.  It analyses particular concepts and practices, addressing holistic approaches in future networks considering a system perspective.  It makes full use of tables, illustrations, performance graphs, case studies and  examples making it accessible for a wide audience.

Chapter 1
Introduction

Konstantinos Samdanis¹, Peter Rost¹, Michela Meo², Christos Verikoukis³ and Andreas Maeder¹

¹NEC Europe Ltd, Heidelberg, Germany

²Politecnico di Torino, Torino, Italy

³Telecommunications Technological Centre of Catalonia, Barcelona, Spain

1.1 Origins of Green Communications

Climate change and energy crisis are not just a vague future problems, as their effects are becoming apparent at a rapid pace. Greenhouse emissions, such as

and methane, cause global warming with catastrophic consequences on planet and on the human society as documented in Ref. [1]. The Kyoto protocol to the United Nations Framework Convention on Climate Change (UNFCCC) established in 1997 indicates that mainly the developed countries are responsible for the current levels of greenhouse gases, followed by a strong objective to take action against global warming. In the Conference of the Parties (COP) 17 climate change conference in Durban, 2011 scientists raised concerns that the measures taken so far are not sufficient to avoid global warming beyond

(a limit established in the G8 meeting in L'Aquila in June 2009 to avoid unpredictable environmental damage) and more urgent action is needed. Besides environmental concerns, the energy crisis becomes apparent with claims stating that approximately 50% of the world petroleum resources are already exploited [2], creating major obstacles for power supply with negative consequences on the economy. In general, energy pricing influenced by fuel prices is showing an increasing trend according to the forecast study performed by the Energy Information Administration (EIA) of the US Department of Energy [3].

As the use of Information Communication Technology (ICT) becomes an essential part of human daily lifestyle allowing social and business interaction on a local and global scale, the pace of development and integration of new technologies is performed on an accelerating rate. According to ITU estimations, Internet users reached around 2.7 billion by the end of 2013, almost 40% of the world's population, whereas mobile cellular subscribers approach 7 billion, with the mobile broadband being the most dynamic market with 2.1 billion subscribers globally [4]. Effectively, such enormous adoption of ICT is accompanied by a massive growth of the number of user devices, wireless, indoor, transport, core and data center networks and services, raising significant cost and sustainability concerns. In particular, ICT across a wide range of applications currently accounts for 5.7% of the world's electricity consumption and 1.8% of

emissions [5], stressing the need for enhancing energy efficiency in ICT products. Data from different telecommunication operators globally confirms their huge consumption of electricity as summarized in Ref. [6].

To comprehend the energy consumption of modern telecommunication systems considering the expected scale of increase, a summary of historic and near-future global traffic volumes for the mature markets over the decade 2010–2020 regarding mobile access, wireline and core networks is illustrated in Table 1.1 [7]. From the traffic growth projections, it becomes evident that there is a significant increase on mobile access, but with the wireline access and core networks still carrying the majority of user traffic. Multimedia applications and particularly video is one of the main contributors of such significantly higher traffic volumes, with Cisco Internet traffic projection forecasting that in 2015 the video consumption will reach one million video minutes per second, which is equivalent of 674 days [8]. Such tremendous data growth also as a consequence of the increasing population of users that can afford ICT services, raises new economic and sustainability challenges for network operators, which face the need of expanding their deployed network infrastructure in order to cope with the continuously increasing traffic volumes. Furthermore, the introduction of novel architectures and technologies, for example, machine-to-machine communications, smart grid, automotive, social media, smart cities, adds an extra degree of complexity to the network design, generating a compulsory need for holistic end-to-end approaches for the network operation.

Table 1.1 Traffic projections between 2010 and 2020 for the mobile access, wireline access and core networks modeled by GreenTouch for the Mature Market segment [7]

	Mature market traffic projections (PB/month)
Year	Mobile access	Wireline access	Core network
2010	161	7,727	10,707
2015	3,858	33,879	45,402
2020	14,266	74,462	103,085
2020/2010	89x	9.6x	9.6x

The telecommunication networks' greenhouse emissions growth rate is expected to continuously increase as illustrated in Figure 1.1. Wireless and wireline networks accounted for an equal share on greenhouse emissions between 2002 and 2011 with a footprint of 0.13 and 0.20 gigatons of

equivalent (GtCO₂e), respectively. However, the remarkably high data volumes in the mobile communications sector and the launch of fourth-generation (4G) long-term evolution (LTE) networks have the consequence of increasing the wireless greenhouse footprint to 0.16 GtCO₂e compared to a wireline equivalent of 0.14 GtCO₂e anticipating the adoption of fiber optics that significantly lower the energy consumption.

Figure 1.1 Telecommunication system emissions between 2002 and 2020 showing wireless and wireline contributions [9]

Besides economic and environmental matters, energy efficiency in telecommunication systems is particularly crucial for developing countries providing a means for bridging the digital divide. In such cases, cost is the main barrier and hence energy efficiency may reduce the operational expenses provisioning affordable ICT services. In addition, green communications relying on alternative energy sources may provide the means of equipping remote areas without or with limited power supply creating an environmental friendly ICT adoption in developing countries. Furthermore, energy efficient mechanisms and practices could prove critical for telecommunication systems in disaster situations, where the power generation or the distribution infrastructure is damaged. Specifically, network equipment that supports a low-power mode may sustain a basic operation available only for critical services.

1.2 Energy Efficiency in Telecommunication Systems: Then and Now

The problem of energy efficiency in telecommunication systems is not entirely new. Indeed, energy efficiency has always been a significant issue for maximizing the battery lifetime of handheld devices and wireless sensor nodes that operate autonomously without a power grid supply. Early solutions considering the field of cellular and portable communications focus on wireless and mobile terminals, notebooks, and personal digital assistants (PDAs). The main objective was to establish power saving modes or states, in where devices either operate with minimal power consumption or simply sleep, that is, freeze their prior operating state. Common examples are the idle mode of global system for mobile (GSM) communication devices or the hibernate/standby mode of laptops and PDAs.

Similarly, studies on ad hoc and wireless sensor networks have devoted major efforts on energy optimization with the goal of extending the entire system lifetime. A plethora of different energy saving techniques including device sleeping patterns, clustering and head selection for minimizing the energy expenditure of the ad hoc or sensor system as well as energy-aware routing and data aggregation protocols have been extensively analyzed [10, 11]. However, these studies concentrated primarily on the energy management of each device considering the ad hoc or sensor network in isolation. Probably the most widely studied energy problem concentrates on the transmission efficiency considering medium access control (MAC) protocols, error correction, and radio channel gain techniques [12]. Again the focus concentrates on the device energy efficiency since transmission and radio optimizations simply reduce the device processing and forwarding.

These early efforts attempt to extend the lifetime of devices without a power supply. Fundamentally, this is different from the current trend of green communications and energy efficiency in ICT, which seeks solutions to reduce the energy consumption and the

footprint of network equipment and ICT systems irrespective of power supply limitations usually at off-peak time or when equipment are not in use. Effectively, strategies, mechanisms, and protocols, which stretch along home and enterprise networks, wireless access and cellular networks, transport, and the Internet, are considered with the goal to introduce adaptive operations based on load variations and new equipment design and system architectures with reduced the energy consumption needs.

Such a green communication vision has also got momentum within ICT government and regulatory bodies, especially since the launch of the Kyoto protocol, which aimed to create policies and recommendations for developing and using ICT equipment and systems. Early efforts from the US environmental Protection Agency concentrated on energy efficiency of personal computers (PCs), peripherals, and monitors, establishing a voluntary labeling program referred to as Energy Star in 1992. The European Commission (EC) recognized since 1999 the need for further actions toward energy efficiency and green communications, introducing the code-of-conduct [13] to drive policies and recommend...

Table of contents

• Cover
• Title Page
• Copyright
• Table of Contents
• List of Contributors
• Preface
• List of Abbreviations
• Chapter 1: Introduction
• Chapter 2: Green Communication Concepts, Energy Metrics and Throughput Efficiency for Wireless Systems
• Chapter 3: Energy-Efficiency Metrics and Performance Trade-Offs of GREEN Wireless Networks
• Chapter 4: Embodied Energy of Communication Devices: Modeling Embodied Energy for Communication Devices
• Chapter 5: Energy-Efficient Base Stations
• Chapter 6: Energy-Efficient Mobile Network Design and Planning
• Chapter 7: Green Radio
• Chapter 8: Energy-Efficient Operation and Management for Mobile Networks
• Chapter 9: Green Home and Enterprise Networks
• Chapter 10: Towards Delay-Tolerant Cognitive Cellular Networks
• Chapter 11: Green MTC, M2M, Internet of Things
• Chapter 12: Energy Saving Standardisation in Mobile and Wireless Communication Systems
• Chapter 13: Green Routing/Switching and Transport
• Chapter 14: Energy Efficiency in Ethernet
• Chapter 15: Green Optical Networks: Power Savings versus Network Performance
• Chapter 16: Energy-Efficient Networking in Modern Data Centers
• Chapter 17: SDN-Enabled Energy-Efficient Network Management
• Chapter 18: Energy-Efficient Protocol Design
• Chapter 19: Information-Centric Networking: The Case for an Energy-Efficient Future Internet Architecture
• Chapter 20: Energy Efficiency Standards for Wireline Communications
• Chapter 21: Conclusions
• Index
• End User License Agreement