In 2007, China Mobile green-lighted the Green Action Plan as part of their ongoing commitment to reduce environmental impact. The plan tightly focuses on saving energy and decreasing emissions by building eco-friendly networks. By using alternative energy and adopting cutting-edge technologies on BTSs and sites, they have quickly implemented new networks in China.
Fresh greenery by Qinghai Lake
"With perfect sincerity and integrity, we will strive to fulfill our triple-sided responsibilities: our economic responsibility, our social responsibility and our environmental responsibility." China Mobile published its 2007 Corporate Social Responsibility Report in February 2008 in a commitment to equate its environmental responsibility with both its economic and social responsibilities. The Green Program, which derives from the Green Action Plan, has been ratified as one of China Mobile's five major programs for 2008.
Focusing on energy saving and emission reduction, the Plan was initiated in early December 2007. Its implementation is based on strategic partnerships with Huawei, three other main equipment suppliers, and over ten auxiliary equipment suppliers. This article provides an account of the Green Mobile Network jointly constructed by Huawei and China Mobile on the picturesque edge of Qinghai Lake.
Green mobile network
Qinghai is a province of China, named after Qinghai Lake. It borders Tibet Autonomous Region on the southwest. China Mobile Qinghai's legacy GSM network was mainly supported by European equipment suppliers. Ageing equipment, however, has resulted in high energy consumption by the network BTSs which, coupled with unsatisfactory communication quality, has emerged as a long-standing problem for China Mobile.
In order to promote network quality and save energy, China Mobile Qinghai and Huawei launched their GSM network adjustment and expansion project in April 2008. Extending across Xining City (the capital of Qinghai Province) and a number of other cities, the scheme involves more than 400 BTSs and is integral to the realization of the Green Action Plan. Moreover, it solidifies China Mobile's selection of Huawei to construct its green trial network in Qinghai.
For operators and equipment suppliers, the green mobile network embodies a complex system that aims to extend beyond simply reducing energy consumption. It must also satisfy a multitude of requirements spanning energy, materials, land, and labor saving. The green network also seeks to reduce operating expenditure (OPEX) and control CO2 emissions in a win-win balance of environmental protection and economic benefits.
The green mobile network is achievable via a number of measures. Initially, advanced technologies such as the Distributed Base Station (DBS) can be applied to the main BTS equipment to realize energy savings and flexible deployment potential. In addition, software upgrades can facilitate the capacity of the major equipment to support multiple systems, reuse hardware, and maximally protect long-term investment.
Secondly, adjustments to intelligent ventilation facilities are necessary to improve equipment room and site construction. Methods such as direct ventilation and natural heat dissipation reduce equipment rooms' air conditioning requirements, while integrated equipment shelter curtails total energy consumption.
Thirdly, natural, clean energy such as solar, wind, and firedamp energy must be applied to BTSs to realize zero CO2 emissions.
Making green action a reality
China Mobile Qinghai's energy saving and emission reduction trial network will verify the green mobile network solution in three major ways: BTS equipment, sites, and green energy.
- BTS energy savings: The origins
It is well known that the mobile access layer uses 90% of the energy totally consumed in a mobile network. High energy-demanding equipment elevates the energy consumed by auxiliary facilities and air-conditioners in equipment rooms, and consequently increases the whole system's total energy usage. Energy savings afforded by BTS equipment are integral to network-wide savings, given that only BTSs can reduce the power needs of auxiliary facilities and air-conditioners. Moreover, green energy sources can only be applied to BTSs which consume low amounts of power.
Huawei's green GSM BTS achieves energy saving and emission reduction in four layers. In the first layer, the BTS employs the power amplification chip and the Doherty-enhanced power amplifier, which are both highly-efficient culminations of the latest technology. Together these have elevated power amplifier efficiency from 33% in 2006 to present levels of 45%, which is forecast to rise to 50% in 2009. In the second layer, green energy-saving software prevents emission and efficiently reduces static power consumption by more than 60% thanks to shutdown technologies such as TRX, timeslot, and channel shutdown. In the third layer, the BTS adopts multi-density TRX and broadband radio frequency technologies to allow a single module to support between four and six carrier frequencies. This gives rise to a smaller and lighter BTS that is less dependent on auxiliary equipment. In the fourth layer, the DBS's Base Band Unit (BBU) can be installed in the reserved space of existing site equipment, such as in the Advanced Power Management (APM) cabinet and the transmission cabinet. At the same time, the RRU can be freely installed on a pole, on a tower, or against a wall.
The Qinghai Lake green network project adopts a series of Huawei's low-energy GSM BTS products, including the BTS3012E, the industry's most energy-efficient macro BTS; the Quadruple Transceiver Unit (QTRU) that supports multi-density TRX module; and the distributed BTS-DBS3036.
The BTS3012E incorporates green energy-saving software that reduces S4/4/4 GSM BTS power to 1000W. This compares with the power of other identically configured GSM BTSs that is 1600W on average. A single BTS3012E saves as much as 5694kWh of energy every year. The average electricity generator produces 1kWh of power for every 300g of coal used. In these terms, a single BTS can save 1.7 tons of coal a year.
The BTS3012E introduces the latest multi-density transceiver QTRU, the application of which positions the BTS3012E as the world's densest BTS. A single basic cabinet supports at most 36 carrier frequencies, or 6 QTRUs, and is able to support a maximum configuration of S12/12/12. The number of cabinets can be reduced by a third, mitigating the conflict between increasingly high traffic and relatively few equipment rooms. Not only are significant CAPEX savings achieved, but standard energy consumption per carrier frequency reduces from 150W/TRX to 55W/TRX.
The DBS3036 comprises the BBU and the Remote Radio Unit (RRU), which combine IP65 outdoor protection and natural heat dissipation. The BBU can be installed against a wall or in any 19-inch cabinet, such as the outdoor APM, while the RRU is installed near to antenna feeders. The two units are connected via optical fibers, which effectively expedites network construction by negating the need for equipment rooms. This solution significantly reduces auxiliary costs and energy consumption.
- Green site construction
Generally, brick and concrete equipment rooms entail considerable time and energy investments in terms of construction, decoration, and other civil engineering.
Based on its experience in various network construction scenarios and with the construction of a genuinely green site in mind, Huawei delivered its Integrated Telecommunication Shelter (ITS) solutions in late 2007.
The ITS provides customers with comprehensive equipment room solutions, which integrate all network and auxiliary equipment, and feature rapid deployment capabilities, low energy consumption, minimized TCO, and high reliability. The ITS1000 and ITS2000 are mutually complementary, and completely lack deployment restrictions, accommodating all terrain including mountains, roofs, and plains.
In this project, the Yanxiao site uses ITS2000 equipment shelter. The ITS2000 forms an integrated communication equipment room based on 10-inch standardized containers. It provides a reliable network operating environment, is theft resistant, accelerates site construction, and reduces energy use.
- Green energy: Nature's gift
Wind and solar power describe two inexhaustible energy sources yielded by nature. Given the increasingly severe global energy pressures, attention is shifting to natural energy sources. This drives technological development in this field, enabling the gradual application of wind and solar power to the communications arena.
Qinghai Province lies in the northwest of Qinghai-Tibet Plateau in the center of northwest China. The whole province sits on a plateau, from which it derives two particular climatic features: 1) intense solar radiation and 2) abundant wind energy. Qinghai is one of the most solar intensive provinces in China, receiving over 2,500 hours of sunshine per year, rendering its solar radiation resources one of the highest nationally. Meanwhile, the western region of the Qingnan plateau and the central and western Qilian mountains create average windspeeds that exceed 4m/s. Moreover, wind power utilization potential exceeds over 5,000 hours across the central and western parts of Qingnan plateau, the Caidam basin, the environs of Qinghai Lake, and the southern area of Hainan mesa.
This unique climate provides the mobile network with rich, natural green energy resources. The complementary wind and solar sources culminate in a comparatively steady power output system that requires no material costs and little maintenance within the lifecycle of its solar power components and wind power generator.
For example, in the Jiayi Village, the network covers all the major lines along Qinghai Lake, which is surrounded by grass land. To ensure required coverage in the tourist season, this scheme adopted the S2/2/4 BTS. This BTS reduced equipment energy consumption to 600W, which laid the foundations for wind and solar energy deployment. To react to solar power interruptions caused by spells of continuous rain, the site implements wind energy as an alternative, thus improving the BTS's reliability. This solution adopts two 1000W wind power generators, twenty-two 160W solar power battery boards, and one group of 12,000AH batteries, which guarantee three days' backup power.
Entering into the green telecom era
In November, 2007, China Mobile cooperated with Huawei to successfully complete GSM network coverage for Mount Qomolangma. Under this scheme, solar power was deployed as the BTS power supply system in several sites. This provides a firm example of the green ethos becoming reality. The beginning of December, 2007 marked the inception of the strategic Green Action Plan agreement between China Mobile and Huawei. The two companies have since been closely cooperating to save energy and reduce emission in a wide range of projects spanning BTSs, core networks, logistics, and business-to-business. Moreover, China Mobile and Huawei have united to construct energy saving and emission reduction trial offices in a range of domestic locations including Sichuan and Qinghai. This demonstrates the partners' joint commitment to implement green schemes and protect the environment.
Mining city gets green
Jixi City, a predominantly coal-mining city of one million population in the northeast of China, expanded their large capacity base stations in the downtown area with equipment rooms that are 83% smaller while cutting energy usage by 70%. Moreover, Enhanced Data Rates for GSM Evolution (EDGE) was realized in the entire network and the over -80dBm coverage areas grew from 76.40% to 94.88%.
Breaking the bottleneck
Jixi is the second largest mining area in China. Like many other areas in the country, there is rapid economic development, fast-growing mobile communications traffic, and communications networks are struggling to keep pace. China Mobile Jixi had an urgent need for bigger capacity and network modifications, and turned to Huawei for an innovative solution after hitting a bottleneck.
The original equipment used a lot of energy and consequently was expensive to operate. In addition, they were at odds with the national energy conservation and environmental protection guidelines. Poor equipment performance and complex networking lead to a continuous rise in operation and maintenance expenditures. The most troublesome issue was that equipment rooms were already full and had no room for expansion. Promotion of network capacity and performance conflicted with energy conservation and the available space.
In April 2008, without extra space for the equipment room or more energy consumption, China Mobile Jixi handily completed the expansion of large-capacity base stations in the downtown area with significantly enhanced performance. The multi-density Huawei QTRU base station made it seamless.
The innovative multi-density QTRU base station is a type of energy saving base station featuring large capacity, small size and low power consumption. This type of base station lets the operator swiftly upgrade the inefficient original mobile network to a high performance future-oriented green communications network.
China Mobile Jixi is now strategically green. During development, a network needs to be expanded every two or three years and the traditional small-capacity GSM base station requires more and more cabinets. If the original equipment room has no extra space, renting a new equipment room is necessary with a corresponding increase in network construction and operation expenditures. The expansion becomes more difficult and more expensive.
In addition, to build a network with large capacity, sound coverage and good performance, a mobile operator has to deploy thousands of base stations. Traditional base stations use a lot of power, making major mobile operators big spenders on energy. Not only do they have growing OPEX, but are also perceived as wasting energy, neither reducing emissions nor protecting the environment.
To meet the telecom network development, Huawei has rolled out solutions that are green and energy saving.
In the third quarter of 2007, Huawei rolled out the GSM multi-density QTRU base station, adopting advanced DPD+Doherty digital power amplification and 3G multi-carrier technologies. At the time of this printing, Huawei is the only vendor who is able to provide the multi-density GSM base station.
The Huawei multi-density QTRU is a type of green base station with large capacity, small size and low power consumption. With the same size of a traditional 12-carrier base station, the multi-density QTRU has three times the capacity. One QTRU RF module supports the processing of six carrier signals and one full-configured QTRU base station supports 36 carriers, while using 50% less power.
For example, to build an S12/12/12 site, three 12-carrier cabinets are typically required, but only one QTRU cabinet is needed. According to 2007 statistics, the typical power consumption of an S12 base station is about 1,300W, whereas a traditional S12/12/12 site consumes about 3,900W. However, the typical power consumption of a Huawei S12/12/12 QTRU base station is 2,000W, or uses nearly 50% less power than a traditional station.
- Saving space and cutting maintenance
At many sites, one QTRU base station can replace three to six traditional base stations. Generally, the configuration of a single QTRU base station exceeds S10/10/10. In most cases, S12/12/12 full configuration is adopted. As a result, the space for two to five base stations is available for future expansion or for 3G base stations. Expenditure on expansion or 3G network building is lowered.
If the capacity of a base station does not reach 36 carriers, a software upgrade can lessen the expansion workload. In the China Mobile Jixi project, 70% less cabinets were needed, from 196 cabinets to 53. It is safe to say that fewer cabinets mean less maintenance hours.
- Energy conservation and emission reduction
The QTRU base station consumes 50% less power than a traditional base station, and the equipment room air conditioners have less to do, making the reduction even greater.
The poorly integrated original equipment used by China Mobile Jixi took up a lot of space. Before replacement, the power consumption per cabinet was 1,500W, with a 36-carrier base station reaching upwards of 6,000W. A Huawei 36-carrier QTRU base station consumes only 2,000W. The overall power consumption per site then drops by 70%, thanks to less power used by the air conditioners.
The QTRU base station truly helps create a green communications network, cutting OPEX with energy conservation and emission reduction.
- Promoting performance and the future
In addition to the advanced power amplification and multi-carrier technologies, the QTRU base station uses advanced digital IF combiner technology to avoid using a traditional combiner, preventing -3dB losses in the high power RF combiner.
The QTRU base station can dynamically adjust the power of each carrier according to the distance between the subscriber and the base station, allowing for a large capacity and wide coverage. China Mobile Jixi used the QTRU base stations to modify the original network to a green mobile network and overall network performance was markedly enhanced. Network coverage is up by 1%. EDGE is realized in the whole network, paving the way to the mobile Internet era.
Energy conservation and environmental protection is a social responsibility for all people. Huawei is implementing a green communications strategy and will invest more in R&D, innovatively designing large capacity base stations with sound performance, high integration, and low power consumption. The success of the Huawei multi-density QTRU base station at China Mobile Jixi definitely colors mobile communications a brighter shade of green.
We only have one earth. For the sake of future generations who will inherit our environmental legacy, Huawei looks to confidently stride into the green telecom era in the spirit of cooperation.