DOES YOUR NETWORK USE MORE ENERGY THAN IT SHOULD?

The GreenTouch initiative hopes to make networks 90% more efficient by 2020.

Internet traffic in the next decade is expected to grow exponentially with the continued dramatic rise of applications, services, devices and machines – all connected to ICT networks. One of the challenges for next-generation networks is their ability to support this traffic in a sustainable and economically viable way. While increased energy consumption is a primary concern with rising energy costs, the environmental impact of networks and socially conscious consumers and service providers are all part of the equation, demanding that our future communication and data networks are greener and more sustainable.

Recognizing this challenge and the growing gap between the traffic growth and the network energy-efficiency improvements, the GreenTouch initiative was formed in 2010. GreenTouch is a global research consortium of equipment providers, operators, research institutes and academic organizations tasked with delivering architectures, specifications and solutions, and demonstrating key technologies that – if combined in an end-to-end network architecture – will enable increasing network energy efficiency by a factor of 1,000 compared with 2010 levels.

The consortium’s initial research indicates the significant opportunity to increase the energy efficiency in today’s communication and data networks, as well as to improve overall network performance and support projected traffic growth. To this end, the group is developing a roadmap of technology assets for a sustainable internet, while also enabling efficient solutions to lower the carbon footprint of other industry sectors touched directly and indirectly by ICT.

To date, GreenTouch has built an extensive research portfolio and strategic research directions around five major themes, including wireline access, mobile communications, switching and routing, optical networking and services, applications and trends. Among the large set of projects, the Large Scale Antenna System (LSAS) and the Bit Interleaved Passive Optical Networks (Bi-PON) technology have recently been showcased in public demonstrations. Recently, GreenTouch conducted and announced a comprehensive research study called the Green Meter that assesses the overall and the relative energy-efficiency benefits possible from the portfolio of technologies, architectures, components, devices, algorithms and protocols being investigated, developed and projected by GreenTouch. It is an assessment of the progress of the consortium toward its goal and an outlook of further opportunities for improving the energy efficiency in communication networks. This is a first-of-its-kind study due to its breadth and depth of technologies being included, encompassing mobile networks, fixed access networks and core networks. The study does not just quantify the energy benefits of a single technology but looks at the end-to-end network perspective and includes a full range of technologies. It also explicitly includes the traffic growth into the calculations of future network energy efficiencies and energy consumption.

Results from the Green Meter study demonstrate that it is possible to reduce the net energy consumption in communication networks by up to 90% by 2020. This dramatic net energy reduction in networks will be made possible through a combination of new technologies, architectures, components, algorithms and protocols, and was calculated taking into account the dramatic increase in traffic. The study’s modeling shows significant improvements in the energy efficiencies of the component networks. These include improvements by a factor 1,043 for mobile networks, a factor 449 for fixed-access networks and a factor 95 for core networks.

The Greentouch Green Meter
To arrive at the Green Meter results, GreenTouch developed network architectures and models that assess the impact of the new technologies, traffic growth projections and their relative impact on the overall power consumption and energy efficiency of communication networks, including mobile, wireline and core networks. Energy efficiency is defined as the ratio of the traffic being carried by the network and the total energy required to support that traffic over the duration of one year. The energy efficiencies in different component networks were evaluated through a combination of forecasting and trend projections, theoretical and analytical calculations, semi-analytical optimizations and network simulation. Some components were also demonstrated through lab implementations and prototyping activities.

The Green Meter is an effective comparison of the energy efficiency and energy consumption of communication networks between the baseline year 2010 and a future reference year 2020. For the baseline year we consider its traffic volumes along with the most energy-efficient, commercially available technologies, which are assumed to be universally deployed throughout the network to support the traffic. It should be noted that this does not necessarily represent a typically deployed network in 2010, considering all the legacy equipment and different technologies deployed that year.

For the 2020 network model we include the most energy-efficient technologies, components and solutions that are being researched by GreenTouch, but also include some other ‘business-as-usual’ evolutions, such as Moore’s Law for electronics. These technologies will not necessarily be universally deployed by 2020 but we believe they are realistic and could be commercially available. The target year of 2020 is chosen as a basis for the projected traffic levels and service requirements to serve as the target requirements for the GreenTouch goals.

For the purpose of calculating the projected network energy efficiency in 2020, it is assumed that the next-generation energy-efficient network equipment, architectures and technologies being considered are deployed throughout the network. This is a projected network scenario and does not fully take into account standardization, development time, commercial availability, deployment times, backward-compatibility and cost.

Of course, such considerations will be taken into account when the technologies are productized and deployed in real networks, but these aspects are beyond the scope and mission of the GreenTouch consortium. Our mission is to investigate new research directions, to invent, develop, demonstrate and de-risk new technologies, and to quantify their impact for future energy-efficient networks.

The Green Meter study includes a whole set of diverse ideas and technologies. Here we provide pointers to some of the technologies being considered, which include, among others:

* For mobile wireless networks: (1) infrastructure-sharing and cooperation between operators for efficient spectrum usage; (2) heterogeneous network architecture with small cells; (3) remote radio heads with free cooling; (4) larger channel bandwidth; (5) micro sleep modes and discontinuous transmission based on traffic volumes; (6) lower power base station hardware; and (7) energy-efficient optical backhauling from all the access points.

* For wireline/fixed-access networks: (1) low-power electronics and photonics components; (2) power shedding; (3) sleep modes; (4) energy-efficient hardware designs; (5) virtual home gateway functionalities; (6) transparent and quasi-passive customer premise equipment; and (7) new data transmission formats and protocols, such as bit interleaved passive-optical networks.

* For core backbone networks: (1) improved components with lower power consumption; (2) mixed line rates; (3) sleep modes; (4) network topology optimization; and (5) optical bypass.

The significance of the Green Meter research is that it demonstrates we can support the predicted traffic growth in future networks, while reducing the total energy consumption of the networks significantly. It also describes a roadmap and a portfolio of technologies for equipment vendors and service providers, and quantifies the relative energy-efficiency benefits of the individual technologies. Deploying these technologies would have a significant economic impact (through reduced operational expenses) and environmental impact (through reduced energy consumption and carbon emissions) for operators and service providers, while at the same time providing value to consumers and businesses and revenue-generating opportunities through the delivered applications and services.

GreenTouch is well on its way to accomplishing its ambitious goals, and through the publication of its research hopes to stimulate discussions, research and focus on energy efficiency in communications networks.