Is 5G truly 'green'? How can operators ensure greater network efficiency?

5G technologies aimed at significant energy efficiency improvements

Sponsored In terms of the amount of data bits delivered for a given unit of energy consumed under different predefined traffic load scenarios, 5G radio access network technology is significantly more efficient than 4G and legacy technologies. This advantage has been made possible through optimized processor and transmitter technologies and implementation of network-sharing mechanisms.

Presently, energy cost already accounts for 20-25% of network total cost of ownership (TCO) for 4G operators. GSMA estimates that high-performing 5G-era mobile networks will require up to 140% more energy in some deployment scenarios.

“Operators' annual electricity expenses for network operation are an important part of their operational expense,” said Mr Jason Tu, Principal Scientist of NFV/SDN at ZTE Corporation. “Power consumption of network is mainly concentrated in four parts: Base station, transmission, power supply and air conditioner of data center.”

While the electricity expense of the base station accounts for about 80% of overall network power consumption, power is mainly consumed by the Remote Radio Unit (RRU) or the Active Antenna Unit (AAU). According to data gathered from ZTE's 5G/4G networks in China, power consumption of a 5G base station is 2.5 to 3.5 times that of a 4G base station.

5G-era energy perspective

Yet, an important purpose of 5G technologies is to improve energy efficiency. 5G technologies will manage significantly higher bandwidth and deliver a higher throughput to serve more users simultaneously than 4G and legacy technologies based on the same energy consumed per bit of transmission.

“The energy efficiency of 5G will be greatly improved considering the bandwidth of 5G,” Mr Tu said. “The targeted energy efficiency improvement of the 5G network exceeds 90% at least.”

To this end, ZTE’s award-winning Massive Multiple Input Multiple Output (MIMO) technology promises both spectrum and energy efficiency. Unlike conventional point-to-point communication, the technology directly sends out signals of the base station like a flashlight to a termination point, minimising energy absorbed by the environment (buildings, pedestrians, trees and cars). Mr Tu added that by converging the energy, it achieves the same signal strength but at up to 10-100 times lower energy consumed.

The good news is that while 5G base stations consume more electricity than 4G counter-parts, their energy efficiency can be about 25 times that of 4G base stations. In some busy hours, based on power consumption of 1000 watts, the 5G base station will support the transmission of 5425 GB traffic, compared with the 4G base station’s 200 GB.

“However, 5G base stations also consume more energy than 4G base stations when the network is idle, so base station shutdown methods should be used to reduce the idle energy consumption of 5G base stations,” suggested Mr Tu.

“In the coming two to three years, a large-scale 5G network will be built around the globe,” said Ms. LiuMingming, VP and General Manager of Cloud Video and Energy Planning Department at ZTE Corporation. Operators adding 5G equipment to existing sites of 2/3/4G networks or building new sites will have to grapple with significant power supply challenges, such as costly and lengthy building up of AC mains capacity or re-location to new sites or both.

Other critical considerations include replacement of cabinets for 5G equipment to increase power capacity. Operators will need to install new power distribution units, replace cables and boost unit configuration for load distribution, and support short-term large-current dis-charge via battery backup. Requirements will be higher for energy supply reliability, stream-lined management, and efficient operations and maintenance (O&M) to support the large number of 5G sites.

Simple, efficient and modular path

Focused on harnessing the potential efficiencies of 5G, ZTE is proposing a 5G power sup-ply architecture that is simple and efficient, modular, intelligent, and networked. It aims to enable faster 5G installations, smooth capacity expansions, efficient energy consumption, and simpler O&M.

ZTE’s key approaches include:

• Extreme simplicity and efficiency: Ultra-efficient and high-power-density power sup-ply is used to build the ZTE One-Cabinet Site. The ZTE PAD power supply and battery are used to build a full-PAD site, thus achieving rapid deployment and reduced construction and operating costs.
• Modularity: A modular architecture design – including the rectifier module, AC/DC power distribution, power sub-rack, power system, heat dissipation component, and energy storage system – facilitates smooth expansion from components to the system, flexible configuration, and investment protection.
• Intelligence: Smart synergy, intelligent control of hybrid energy, smart shaving, intelligent lithium battery, and intelligent O&M boost energy efficiency and reduce operating expenses.
• Networked energy: An intelligent platform harnesses big data and artificial intelligence (AI) to provide multi-level and multi-service network energy management that enables customers to develop value-added services with lower O&M effort and cost. For example, ZTE’s AI-based PowerPilot 4G/5G solution identifies services, analyses service energy efficiency, and actively navigates services to the most appropriate network layer to attain the lowest energy consumption per bit of data.

As network operators seek enhanced and efficient network energy consumption in their 5G deployment strategies, one major consideration is to consider attracting more traffic first since the peak energy efficiency of 5G networks can only be much higher than that of 4G networks. “More traffic will lead to high efficiency and lower network access cost per bit,” explained Mr Tu.

Compared to 4G, 5G’s greater bandwidth and energy efficiency clearly creates opportunity for significant network cost reduction. This will make it feasible for more low-value Internet of Things terminals to be connected to the network. Other measures to save energy include the AI-based base station shutting down automatically at night when network traffic is low.

Mr Tu added that since 5G’s energy efficiency exceeds that of 4G, and that of 4G is better than that of 3G, it is good strategy to implement 3G spectrum refarming to 4G or even 5G.

At the same time, “the conversion efficiency and power density of the power supply system are key indicators for energy efficiency improvement,” pointed out Ms Liu. “The new-generation super-efficient rectifier launched by ZTE increases the conversion efficiency from 96% to 98%, reducing the loss by 50%. The rectifier with higher power density is un-der test, which will further improve energy efficiency and reduce power usage. Modular power supply product with large capacity, ultra-high efficiency, ultra-high power density will become the first choice for 5G base stations.”

The cooling system of the data centre is another major source of energy consumption. Ad-dressing this, ZTE’s indirect evaporative cooling system harnesses natural cooling sources to cool equipment rooms, especially in hyper-scale data centres, to enable energy savings of up to 60% while achieving fast deployment and easy O&M.

As power consumption and the number of sites in the 5G network increase, requirements will escalate for energy storage density, charging and discharging performance, and intelligence. For instance, traditional lead-acid batteries cannot meet the requirements of 5G networks’ rapid development. Replacing lead-acid batteries with lithium batteries has been an inevitable trend.

But ordinary lithium batteries lack intelligence capabilities to effectively solve 5G network problems in deployment, capacity expansion, O&M and management. For this reason, ZTE’s smart lithium batteries feature 5G-focused capabilities such as intelligent mixed use, voltage increase, anti-theft, parallel operation, and cloud management.

All these evolving solutions continue to improve the integrated intelligence level of 5G net-work power supply. By doing so, they help to maximize network power supply efficiency and reduce TCO.

Sponsored by ZTE Corporation