5G innovation promotes green and low-carbon development

Energy conservation is the key support for achieving the goals of "carbon peak and carbon neutrality". The accelerated development of new-generation information technologies such as 5G has provided networked, digital, and intelligent technical means for the green development of the economy and society, and has become an important engine for promoting social energy conservation and emission reduction.

In the three years since the issuance of 5G licenses in my country, 5G commercial development has been rapid. The integration of 5G and other ICT technologies has initially shown results in enabling the digital transformation of thousands of industries. New formats and models are constantly being explored, helping the digital economy to show a vigorous development momentum. 5G has accelerated the digitalization process of various industries and promoted energy conservation and emission reduction in the whole society. It also urgently needs to move towards green and low-carbon. The energy consumption per bit of 5G is 1/5 of that of 4G, but the peak rate has increased by 20 times. The overall energy consumption of 5G networks is higher than that of 4G. The high power consumption and cost of 5G base stations have attracted widespread attention. According to GSMA data, the energy consumption cost (electricity bill) of communication networks accounts for as much as 20% to 40% of operators' operating expenditures (OPEX). Under my country's "dual carbon" goal, 5G energy conservation and emission reduction are imminent. It is urgent to accelerate the research of 5G network energy-saving technologies and explore the path of green development of 5G networks.

Building Green 5G with Both Soft and Hard Approaches

5G is not a "natural power hog". Its power consumption per bit is 80% lower than that of 4G. However, as communication operators increase the construction of 5G base stations, the number of 5G base stations has increased significantly, and data traffic has exploded. The overall power consumption is 2.5 to 3.5 times that of 4G base stations. "The main energy consumption of mobile operators lies in the wireless access network, that is, the wireless base station. Research in the industry shows that due to the huge number of base stations, the energy consumption of the wireless access network may reach about 70% of the energy consumption of the entire network." Yang Guang, a senior analyst in the field of wireless communications at SA, said in an interview with reporters.

Liu Qiang, director of the Energy Teaching and Research Section of the Institute of Quantitative and Technical Economics of the Chinese Academy of Social Sciences, believes that 5G is currently in a large-scale construction period. The 5G network is not only a connection between people, but also extends to the connection between people and things, and things and things. As a result, the increase in 5G energy consumption is naturally very significant. Liu Qiang said: "In addition to the energy consumption of wireless networks, core networks, transmission networks, data centers and other management and operations, infrastructure construction itself also has indirect energy consumption, such as steel, cement, etc. The construction of infrastructure such as base stations and computer rooms will also generate indirect energy consumption. In addition, we must deal with 6G and Musk's "Starlink Project" or other situations that may compete with 5G, which may also lead to a sharp increase in energy consumption."

With the continuous advancement of mobile communication technology, multi-frequency and multi-standard networks will coexist for a long time. So how can we help operators reduce network energy consumption while meeting performance requirements? Relevant experts pointed out that first of all, multi-frequency technology needs to be introduced into wireless networks. A device supports multiple frequency bands and realizes dynamic power sharing between frequency bands, which can greatly improve energy efficiency. Secondly, multi-antenna technology needs to be introduced. Through multi-antenna technology, the coverage capability of base stations can be greatly improved, the number of base stations can be reduced, and seamless and comprehensive coverage can be achieved. In these ways, the energy consumption of operator networks can be reduced.

In view of the high energy consumption of 5G networks, the industry needs to strengthen the research on energy-saving technologies to continuously reduce the energy consumption of equipment and networks. In this regard, experts from the China Academy of Information and Communications Technology pointed out that according to the consensus of the industry, the industry generally adopts a three-level architecture of equipment level, site level and network level to carry out research on key energy-saving technologies and related evaluation systems.

Key technologies for equipment-level energy saving include hardware energy saving and software energy saving. For example, China Telecom has guided the industry chain to adopt new materials, new architectures and improved integration in 5G hardware to further reduce the basic power consumption of base stations; in terms of 5G software functions, it has adopted methods such as symbol shutdown, carrier shutdown, channel shutdown and deep sleep to continuously improve the refinement and intelligence of software energy saving and continuously reduce the power consumption of base station operation.

The key technologies for energy saving at the site level are mainly aimed at the energy saving of supporting facilities such as air conditioners and power supplies that constitute the site together with the main equipment. At present, the energy consumption of supporting facilities is mainly reduced by exploring new wireless access network architectures. For example, China Mobile has jointly developed high-efficiency materials, new devices, and new structures for base stations with industry partners, achieving a 35% reduction in the power consumption of a single 5G station compared to the initial commercial use, which is close to 2.5 times that of 4G; it has carried out exploration and verification of energy-saving dynamic voltage regulation, BBU sleep and pooling, and achieved large-scale deployment and performance optimization of energy-saving functions such as sub-frame silence, channel silence, shallow sleep, and deep sleep. It has put 5G base station devices into sleep mode based on business load, achieving 10%~30% power saving in low-load scenarios and more than 50% power saving in extremely low-load scenarios.

"The supporting equipment of base stations, such as air conditioners, are often large energy consumers. By adopting new system designs and new heat dissipation designs, we can also lower the ambient temperature requirements for base station operation, thereby reducing air conditioning energy consumption." Yang Guang said.

The key technology for network-level energy saving is to carry out multi-network collaboration by combining artificial intelligence algorithms. Network-level energy saving technology is closely related to network operation. By collecting data and processing big data on the network management side, it can automatically identify coverage cells and capacity cells in multi-frequency and multi-mode network states, and perform timely cell silencing and awakening, which can effectively achieve energy saving effects.

"It is necessary to consider the overall network energy consumption from the network perspective. For example, we can take advantage of the volatility of network business traffic. During business low periods, while ensuring network coverage, we can appropriately shut down some carriers or even some base stations, which can significantly reduce network energy consumption. In addition, the early replacement of old equipment with new equipment is also conducive to improving network energy efficiency. The energy efficiency of new 4G and 5G base stations is much higher than that of old 2G and 3G base stations. The early withdrawal of 2G and 3G from the network will also help improve the energy efficiency of the entire network." Yang Guang said. For example, in order to reduce the energy consumption of 5G base stations and realize large-scale commercial use, China Unicom has proposed a "deep sleep" energy-saving algorithm and system-level intelligent energy-saving technology. After three years of hard work, compared with the initial stage of 5G construction, China Unicom has achieved a 60% reduction in 5G idle energy consumption and a 30% reduction in comprehensive energy consumption, making 5G base stations initially capable of large-scale commercial use.

Energy conservation and emission reduction is a systematic project

The 2022 Mobile Net Zero Emissions Report recently released by GSMA shows that although mobile network data traffic increased by 31% last year, related carbon emissions only increased by 2%, which means that the industry has achieved phased results in green and low-carbon mobile communication networks.

Energy conservation and emission reduction is a systematic project involving all aspects of measures, which depends on the joint efforts of the entire industry and even the whole society. Many companies including Huawei, ZTE, CITIC Mobile, Ericsson, Nokia, etc. have helped operators to save energy and reduce consumption in all aspects at the component level, equipment level, network level, etc., and have made continuous progress.

"Reducing energy consumption is an issue for the entire industry chain, and requires the joint efforts of operators, system equipment manufacturers, component manufacturers, and even supporting manufacturers such as power supplies and air conditioners. While reducing energy consumption, we can also expand the application scope of new energy and use more renewable energy such as solar energy and wind energy to power network equipment, which will also help achieve the goal of reducing carbon emissions." Yang Guang suggested.

At present, "carbon peak and carbon neutrality" have become a consensus of the whole society. Improving network energy efficiency and reducing carbon emissions are social responsibilities that telecom operators must bear. On the other hand, energy consumption costs are also an important part of network operating costs. With the continuous growth of data traffic carried by the network, improving energy efficiency will help operators control costs and improve profitability. Therefore, energy conservation and consumption reduction are of great significance to the sustainable development of operators, both from the perspective of business operations and social responsibility.