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Green 5G Lights the Way to Low-Carbon

What are the major strategies, solutions, and technological directions for ensuring that 5G is positioned at the vanguard of green ICT?

By Jiang Xudong, President of Huawei's SRAN Product Line

Although GSMA reports that telecommunications represents just 0.4% of global carbon emissions, operators have extended their green strategies from minimizing network-derived carbon emissions to boosting energy efficiency in vertical industries. Equipment vendors must therefore innovate green products and solutions to help operators build green 5G networks and achieve net zero goals while fulfilling growing demand for diverse services.

1.5°C threshold and 1:10 enablement

Climate change is one of the most pressing global challenges and one that will have a huge impact on future generations. In its latest report Climate Change 2021: the Physical Science Basis, the Intergovernmental Panel on Climate Change (IPCC) found that once rare weather extremes have become more common. For example, severe heat waves that happened only once every 50 years are now happening roughly once a decade. 

UN Secretary-General António Guterres warns that, "We are at imminent risk of hitting 1.5 degrees in the near term. The only way to prevent exceeding this threshold, is by urgently stepping up our efforts, and pursuing the most ambitious path."

Another GSMA report, The Enablement Effect, concludes that, "With a European and North American scope, mobile technologies had a 1:5 enablement ratio compared to the footprint of the industry in 2015." 

This means that one kWh of power consumed by mobile networks will lead to a 5-kWh reduction in electricity used by other industries. GSMA believes the ratio will rise to 1:10 by 2025.

Operators globally have introduced clear targets for energy conservation and reducing carbon emissions. At its carbon peak and neutrality conference on July 15, 2021, China Mobile announced that it plans to cut carbon emissions by 1.6 billion tons in the next five years, after achieving a reduction of 800 million tons from 2016 to 2020. It will also expand the use of 5G to help verticals raise energy efficiency and reduce carbon emissions. For example, the operator has teamed up with education companies to provide online learning services for primary and secondary school students based on cloud platforms, serving 400 million users and cutting carbon emissions by 23 million tons compared to traditional methods.

The Drivers of Efficiency

Customer-driven efficiency gains

During more than 20 years of developing wireless technologies, we've prioritized developing green products, and solutions geared towards boosting network energy efficiency. The best innovations are customer-driven and based on understanding customer pain points before development begins.

Distributed Base Stations

In 2005, Huawei launched the first-ever distributed base station. By moving RF modules from indoor equipment rooms to outdoor sites closer to antennas, distributed base stations improve signal quality while reducing air-conditioning costs. They minimize cable loss and overcome insufficient space and cooling capacity.

SingleRAN

Launched in 2007, the Huawei SingleRAN solution changed how sites are deployed and relaxed deployment requirements by enabling one RF module to work on multiple bands and support multiple radio access technologies. Operators could then more easily adapt to different access technologies, build converged networks, and smoothly evolve their networks. Using 50% less power than traditional solutions, SingleRAN was first deployed in Europe and is now mainstream worldwide, contributing heavily to energy savings and lower electricity bills.

PowerStar

Global operators once showed mixed attitudes towards software energy-saving functions — they were enthusiastic about potential energy-efficiency improvements, but concerned about degraded network performance. This dilemma ended in 2018 when Huawei launched its unique energy-saving solution, PowerStar, which uses AI to help operators balance energy use and network performance. More than 50 operators have deployed the solution in live networks. In China, 800,000 sites are running PowerStar, saving 400 million kWh per year.

Green 5G 

The ITU has set the objective of reducing ICT carbon emissions by more than 45% by 2030. Many operators have announced their own carbon neutrality targets and action plans, including for 5G.

We've moved to establish a green network assessment system based on energy efficiency and developed eight technological directions for building green 5G target networks. From the perspective of network evolution, these suggestions will be key to helping operators achieve their strategic carbon goals.

What makes a network green?

A networks vary in scale, energy efficiency is a better measure than absolute energy use. Moreover, as networks develop at different stages and serve different purposes, energy efficiency should consider two factors: traffic and experience. Traffic links to energy consumption based on demand. Experience relates to how controlling user experience can control energy use.

We've made significant advances in site integration, site simplification, and intelligent networks. Moving forward, networks must be less dependent on natural environments.

Eight Directions 

In addition to standards for measuring green networks, technological directions are essential if operators are to develop green 5G networks.

Direction 1: Multi-antenna RF reduces per-bit energy consumption and increases transmission efficiency: 5G AAU uses a multi-antenna, multi-channel architecture, and spatial multiplexing to significantly boost system capacity. Signal phases and amplitudes can be tweaked to concentrate radio energy in narrower beams that point to users more precisely, increasing energy transmission efficiency and ramping up per-bit energy efficiency. Our test results show that the energy efficiency per bit of 64T64R modules is 20 times higher than it is in 4T4R modules. The AAU will become an essential tool for operators to meet constantly growing traffic demand from individuals and industries.

This year, we added a new component to the AAU — an ultra-large antenna array. It includes new baseband algorithms and energy-saving antennas that theoretically consume 30% less electricity but deliver the same level of coverage and experience for users in cell-edge areas.

Direction 2: Ultra-broadband multi-band devices reduce energy consumption: Higher integration enables a device module to expand its RF capability from single to multiple bands and provide ultra-large bandwidth. This transforms site construction from deployment of one band on one RRU or AAU module to one integrated module that supports multiple bands. Operators can use one module to provide various services that previously required multiple modules, lowering costs and overall energy consumption.

One of our customers in the Netherlands replaced two RF modules on 800 MHz and 900 MHz with one ultra-broadband RF module that can provide services on 700 MHz, 800 MHz, and 900 MHz bands using the same amount of power. 

Direction 3: Hardware enhancement for nearly linear power usage changes with varying load levels to reduce low- and medium-low energy consumption: RF hardware transmits at higher efficiency as traffic loads increase. Refined, granular hardware sleeping mechanisms can shut devices down more responsively and at deeper levels when traffic loads are low, wasting less power, increasing the overall RF efficiency of hardware modules in low-traffic periods, and boosting device reliability.

Operators in China have demonstrated that deep hibernation can reduce power consumption by more than 60% in networks under a light load.

Direction 4: Simplified sites without equipment rooms and air conditioners: Air conditioning accounts for 30% to 40% of total site energy consumption. We have proposed two directions: 

A centralized BBU deployment can enable one air conditioner to cool multiple sites rather than one air conditioner cooling one site, and liquid-based and natural cooling methods are a good option for equipment rooms. China Unicom has saved 17,000 kWh of electricity in each site per year with centralized BBU deployment. 

Outdoor equipment cabinets are better choices. One site, one cabinet, and blade site deployment can replace one air conditioner at each site. With one site and one cabinet, cooling media works closely with heat-producing devices, facilitating precise and targeted cooling, which slashes energy consumption. Blade site deployment focuses on saving energy by mounting devices on poles, which maximizes the effect of natural cooling, producing a 60% to 97% increase in energy efficiency.

Direction 5: Linked site energy improves comprehensive energy efficiency: Power feeding and consumption systems, such as power supplies and transmission systems, are "dumb devices" that cannot sense each other, collaborate, or sense service load and running status, thus wasting energy and lowering efficiency.

Linking services to site power supply, storage, and use for increased efficiency is a major direction for green sites. Services and solar power, power supply, battery, the main grid, and temperatures should be linked to enable precise, real-time control on temperature and power operations in line with service loads to ensure efficient energy usage. 

Based on one of our cases in Greece, solar power can produce more than 50% of the total energy of a site linked to solar generators, substantially cutting carbon emissions.

Direction 6: Intelligence for energy-saving and network performance: Intelligent technologies can adapt spectrum and many other resources to real-time service changes and service scenarios in networks.

Launched in 2018, PowerStar was designed with intelligent technology to lower network energy consumption. This year, PowerStar2.0 adds a number of enhancements such as extending energy-saving periods from off-peak hours to all day, expanding three energy-saving dimensions to four, and narrowing KPI optimization down from days to seconds. Operators can double the energy-saving effect and deliver the same network performance.

The commercial deployment of PowerStar2.0 in China's Sichuan province has lowered energy consumption in mobile networks by more than 25%.

Direction 7: Switching services to 5G can maximize energy-efficiency advantages: 4G is 7 to 10 times more energy-efficient than 3G, and 5G is 20 times more efficient than 4G. And its energy efficiency will improve exponentially as it continues to evolve. 

Statistics on mobile networks in Hangzhou, China, show a 3.5-times increase in energy efficiency from 2019 to 2021, even though just 20% of network traffic is carried on 5G networks.

Direction 8: Full-Lifecycle recycling reduces dependence on natural resources: Procedures like design, manufacturing, and transportation are equally as important to a low-carbon future. For product packaging, for example, we've developed a dual-density expanded polypropylene (EPP) process. Two different-density materials can improve cushioning and recycle materials can reduce the size and volume of packaging and materials. 

These eight directions represent our E2E commitment to sustainability. We will continue to work closely with operators and partners to help operators build green 5G networks and enable verticals to use less energy and cut carbon emissions.