Control the power of your network – Power-saving software for your network

Hana Gazoli   November 20, 2023

Much has been said of the power consumption of 5G networks. The expectations across the industry are for a significant increase. Exact estimates differ by source, but MTN says the industry consensus is that 5G will double to triple energy consumption for mobile operators, once networks scale. As a result, awareness of the issue has caused the standards bodies to include specific measures in the standard to improve power efficiency.

Powering 5G networks is becoming a tough-to-afford luxury

Consumption increases are attributed to a number of factors:

i. More energy is required to power a higher capacity network- Due to the increases in throughput, advanced mobile networks consume an increasing amount of power, a trend that began before 5G. The simple fact is that high-speed, high capacity networks require a lot of juice and the past 20 years have seen a tenfold increase in energy requirements.

ii. The introduction of massive MIMO- It takes nearly double the amount of energy to power a 5G cell site using a massive MIMO (multiple input, multiple output) array than it does a standard 4G cell site. According to Chris Nicoll, principal analyst with ACG, a 4G cell site currently uses about 6 kilowatts to power a three-sector, 12-radio antenna. A 5G cell site using massive MIMO technology uses 10 kilowatts of power and with wide adoption of massive MIMO, those energy requirements will likely double again in the next couple of years.

iii. New components- According to Huawei data on RRU/BBU needs per site, the typical 5G site has power needs of over 11.5 kilowatts, up nearly 70% from a base station deploying a mix of 2G, 3G and 4G radios. 5G macro base stations may require several new, power-hungry components, including microwave or millimeter wave transceivers, field-programmable gate arrays (FPGAs), faster data converters and high-power/low-noise amplifiers. It is estimated that telcos spend on average 5-6%(!) of their operating expenses (excluding depreciation and amortization) on energy costs. Clearly any increase in this budget item will strain their profit margins and jeopardize the ROI for 5G upgrades.

Power savings may be the key to profitability

The 5G standard and evolutionary improvements to equipment have combined to make 5G networks more power efficient than 4G, on a watt/bit basis. However, these are minor tweaks in comparison with the overall rise in power consumption of 5G, so the energy bill will continue to grow for mobile network operators.

With the right ecosystem and smarter software solutions, however, there are a number of interesting options to reduce power consumption.

• Micro-sleep- The 5G standard allows gaps in transmission up to 20 ms for 5G Standalone and 160 ms in 5G Non-Standalone mode, which are 100 to 800 times longer than what is allowed in LTE. The requirements for maintaining “always-on” signaling have also been relaxed, so components can be put in power-suspension, or sleep mode, more often and for longer durations. These micro-improvements, which occur millions of times a day, have the potential to reduce overall energy consumption.

• Full 5G SA- Early 5G NSA implementations rely on LTE for control-plane communications and add more processing (and power) demand as a result. As 5G SA adoption grows to cover a larger part of the network, the efficiency (consumption on a watt/bit basis) will improve. In addition, 5G standards include a “Lean Carrier” design that is intended to reduce energy consumption by up to 60% over legacy 4G networks. Deploying an end-to-end 5G ecosystem that is compliant with specifications will unlock those power savings.

• Adaptive transmission power- 4G LTE antennas apply an egalitarian approach to individual users within the cell service area, so each device receives the same “energy attention” from the antenna, regardless of factors such as distance from the cell, current traffic, interference and overlap with adjacent cells. Smarter RAN equipment allows adaptive transmission power, ensuring that the correct energy level is applied to each transmission.

• Implementing a cluster-based architecture- Relying on BBUs at the cell site level to apply available cell resources effectively is wasteful and prevents a broader, more efficient use of network resources. Adopting a cluster-based architecture allows broader flexibility to selectively power-down under used cells, reduce transmission power of adjacent cells to minimize overlapping signals and achieve schedule and spectrum efficiency to reduce interference.

Making the right technological choices

In order for a mobile network to be in position to benefit from the above power savings, there are a number of underlying decisions to be made. For example, many software improvements use advanced machine learning and AI to model usage and resource allocation policies. The rate of development of such software cannot be synced with hardware development, and indeed cannot be limited to specific hardware vendors. Furthermore, hardware vendors have different roadmap priorities than software vendors, so it is likely that software specialists will be better and faster at providing power saving solutions. Breaking the locks of a vertically integrated ecosystem, for example by adopting an Open RAN architecture, is necessary in order to be able to apply the most advanced software with whichever hardware has been deployed.

Furthermore, on the control plane, deploying solutions that support a cluster-based architecture is a key step to unleash network-wide optimization of resources, equipment and energy consumption. This can lead to lower power consumption of each cell as well as fewer cells.

Energy costs will continue to appear as a central item in the budgets of mobile network operators for the foreseeable future. Increases in power consumption will drive the profitability of those budgets dangerously lower. In order to prevent these costs from skyrocketing in the future, operators need to start applying power saving measures at every level right now.