Greener, Energy-Efficient and Sustainable Networks: State-Of-The-Art and New Trends

Abstract

Although information and communications technologies (ICTs) have the potential of enabling powerful social, economic and environmental benefits, ICT systems give a non-negligible contribution to world electricity consumption and carbon dioxide (CO₂) footprint. This contribution will sustain since the increased demand for user's connectivity and an explosion of traffic volumes necessitate continuous expansion of current ICTs services and deployment of new infrastructures and technologies which must ensure the expected user experiences and performance. In this paper, analyses of costs for the global annual energy consumption of telecommunication networks, estimation of ICT sector CO₂ footprint contribution and predictions of energy consumption of all connected user-related devices and equipment in the period 2011-2030 are presented. Since presented estimations of network energy consumption trends for main communication sectors by 2030 shows that highest contribution to global energy consumption will come from wireless access networks and data centres (DCs), the rest of the paper analyses technologies and concepts which can contribute to the energy-efficiency improvements of these two sectors. More specifically, different paradigms for wireless access networks such as millimetre-wave communications, Long-Term Evolution in unlicensed spectrum, ultra-dense heterogeneous networks, device-to-device communications and massive multiple-input multiple-output communications have been analysed as possible technologies for improvement of wireless networks energy efficiency. Additionally, approaches related to the DC resource management, DCs power management, green DC monitoring and thermal management in DCs have been discussed as promising approaches to improvement of DC power usage efficiency. For each of analysed technologies, future research challenges and open issues have been summarised and discussed. Lastly, an overview of the accepted papers in the Special Issue dedicated to the green, energy-efficient and sustainable networks is presented.

Keywords: 5G; ICT; IoT; data centre; energy-efficiency; green; networks; power; sustainable; wired access; wireless.

Figure 1

Estimated: (a) contribution of different industry sectors to global carbon-dioxide equivalent (CO_2e) reduction by 2030 [1], (b) information and communications technology (ICT) sector CO_2e “footprint” contribution and enabled reductions to global CO_2e emissions expressed in Gt [2].

Figure 2

Estimation of (a) costs for the global annual energy consumption of telecommunication networks in period 2011–2025 [2], (b) expected total annual energy consumption per different ICT systems in period 2010–2030 [10].

Figure 3

Estimations of energy consumption of all connected user-related devices and equipment for the period 2011–2025 [3].

Figure 4

Estimated network energy consumption for main communication sectors in: (a) 2013 and (b) 2025 [3].

Figure 5

Techniques for energy-efficiency improvement of radio access networks.

Figure 6

Techniques for energy-efficiency improvement of data centres.