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The rollout of 5G technology promises faster speeds, lower latency, and the ability to support an ever-growing number of connected devices. However, as with any major technological advancement, 5G brings its own set of challenges—one of the most pressing being energy efficiency. As we transition into this new era of connectivity, the need for sustainable solutions to manage the energy demands of 5G networks has never been more critical. This blog explores the energy efficiency challenges posed by 5G and highlights emerging technologies aimed at creating greener communications and networking systems.
For over a century, communication networks have been designed with a focus on optimizing performance metrics such as data rate, throughput, and latency. However, in the last decade, energy efficiency has emerged as a crucial metric, driven by economic, operational, and environmental concerns. The Information and Communications Technology (ICT) industry, responsible for approximately 10% of the world’s energy consumption, has made energy efficiency a key performance indicator (KPI). As we transition to the next generation of wireless communications, energy efficiency is becoming even more critical as it severely effects the human life on the earth surface mainly on two factors global warming due to CO2 emission and sea level raise.
Traditional mobile networks spend about 15 to 20 percent of overall power consumption on actual data traffic. The unused energy is wasted. Increasing energy efficiency has a huge potential to harness wasted power and deploy new technologies, which would further reduce power consumption. On this subject, the progress made is substantial and documented: each transition from one generation of networks to another has brought about a gain of a factor of 10 in energy efficiency.
The Energy Efficiency Challenge of 5G
As communication networks evolve, the demand for data rates, spectral efficiency, and quality of service continues to increase, leading to higher energy consumption. In 2015, fixed access networks consumed about 167 TWh of electricity, while wireless networks used around 50 TWh. That’s a big number – 1 TWh is a trillion watts/hour. For perspective the average American household consumes 7,200 kWh of electricity per year. With the advent of 5G, the challenge intensifies.
The benefits of 5G are well-documented: ultra-fast data rates, massive connectivity, and the ability to support a wide range of applications from smart cities to autonomous vehicles. However, these benefits come at a cost—specifically, a significant increase in energy consumption. Although 5G promises faster internet, smart cities, driverless cars, and an “internet of things” (IoT) revolution, it could also potentially consume up to 1,000 times more energy than today’s networks.
5G networks require a denser infrastructure of base stations and antennas to deliver the promised performance, leading to higher energy demands compared to previous generations. This surge in energy consumption presents a paradox. While the goal is to deliver higher data rates and more reliable connections, achieving this with constant energy efficiency could result in a proportional increase in energy usage.
Energy efficiency in 5G is measured by the number of bits transmitted per Joule of energy expended. Given that electricity costs represent about 70% of the operational expenses in mobile services, improving this metric is not just an environmental necessity but also an economic imperative. Current cellular sites delivering 28Mbit/sec has an energy consumption of 1.35kW, leading to an EE of 20 kbit/Joule. As 5G networks begin to deliver data rates as high as 1 Gbps, maintaining or improving energy efficiency becomes a significant challenge.
A general concern is that higher data rates can only be achieved by consuming more energy; if the EE [energy efficiency] is constant, then 100× higher data rate in 5G is associated with a 100× higher energy consumption.” In addition, with an explosive number of heterogeneous devices coming online, including sensors for home security, tablets, and wearable health monitors, the computational power of base stations must increase. An estimated 50% increase in the computing power of baseband units has been predicted to handle this traffic burst.
Moreover, the sheer volume of data being processed and transmitted across these networks further exacerbates the energy consumption issue. The computational power required for base stations to handle the growing number of connected devices—estimated to increase by 50%—further exacerbates the energy challenge.
As a result, there is growing concern about the environmental impact of 5G and the sustainability of its widespread adoption.
The Push for Green Communications and Networking
Recognizing the urgency of the situation, the design of 5G networks is placing energy efficiency at the forefront. 5G design requirements mandate that energy use be reduced to 10% of that of current 4G networks. This goal encompasses various strategies, from reducing power requirements for radio base station antennas to extending the battery life of smartphones and IoT devices.
5G design requirements specify that energy use be reduced to 10 percent of current 4G networks. This includes reducing power requirements for radio base station antennas, as well as client devices such as smartphones and IoT devices to extend battery life. The future goal is Green communications and networking comprising sustainable, energy-efficient, energy-aware, and environmentally aware communications and networking.
Emerging Technologies for Green Communications and Networking
To address these challenges, researchers and industry leaders are developing innovative technologies and startegies that enhance the energy efficiency of 5G networks. Here are some of the key innovations driving green communications and networking:
1. Energy Efficiency Technologies:
Emerging technologies like caching and mobile computing can further reduce energy consumption. By intelligently distributing frequently accessed content across the network, caching reduces the need for energy-intensive backhaul transmissions.
Energy-Efficient Hardware
One of the most direct approaches to reducing the energy consumption of 5G networks is the development of more energy-efficient hardware components. This includes the design of low-power base stations, antennas, and network equipment that can operate with minimal energy while maintaining high performance.
Energy-efficient hardware encompasses a variety of strategies, including the green design of RF chains, streamlined transmitter/receiver structures, and the adoption of network function virtualization. Simplified transmitter and receiver architectures, such as coarse signal quantization (e.g., one-bit quantization) and hybrid analog/digital beamformers, are particularly effective in enhancing hardware energy efficiency, especially in systems like massive MIMO and mmWave.
Designing energy-efficient hardware, including simplified transmitter/receiver architectures and hybrid analog/digital beamformers, is critical. Cloud-based implementations of the radio access network (RAN) and the use of network function virtualization (NFV) are also key to reducing energy consumption.
Foe smartphones The goal for 5G devices is to increase battery life to at least three days and up to 15 years for cellular IoT devices Advances in semiconductor technology, such as the use of gallium nitride (GaN) instead of traditional silicon, are helping to create more efficient power amplifiers and other critical components.
Addressing Network Energy Consumption
To effectively tackle network energy consumption and carbon emissions, a holistic approach is required. This involves modernizing hardware and software, addressing both new and existing network components. Ericsson emphasizes that improving energy efficiency involves not just individual products but the entire network ecosystem, integrating advanced technologies and sustainable practices to achieve comprehensive energy and carbon reduction.
Energy Harvesting and Transfer:
Innovative techniques such as environmental energy harvesting (using solar or wind energy) and radio-frequency energy harvesting (recycling energy from radio signals) are being explored to power communication systems sustainably.
Two main kinds of energy harvesting have emerged so far in the context of wireless communications.
– Environmental energy harvesting. This technique refers to harvesting clean energy from natural sources, such as sun and wind. The main challenge in the design of communication systems powered by energy harvesting is the random amount of energy available at any given time. This is due to the fact that the availability of environmental energy sources (e.g. sun or wind) is inherently a stochastic process, and poses the problem of energy outages.
– Radio-frequency energy harvesting. This technique refers to harvesting energy from the radio signals over the air, thus enabling the recycling of energy that would otherwise be wasted. In this context, interference signals provide a natural source of electromagnetic-based power.
The idea is to combine energy harvesting with wireless power transfer techniques, thereby enabling network nodes to share energy with one another. This has a two-fold advantage. First, it makes it possible to redistribute the network total energy, prolonging the lifetime
of nodes that are low on battery energy. Second, it is possible to deploy dedicated beacons in the network, which act as wireless energy sources, thereby eliminating or reducing the randomness of the radio-frequency energy source.
Simultaneous Wireless Information and Power Transfer (SWIPT)
In 5G networks, a promising technology is Radio Frequency (RF) harvesting, which involves converting energy from transmitted radio waves into usable power for devices or infrastructure like microcells and antenna arrays. This approach leverages the dual nature of RF signals, which can carry both information and energy. The concept of Simultaneous Wireless Information and Power Transfer (SWIPT) exploits this by enabling the transmission of information and the transfer of power from the same RF signal. This innovative scheme allows for the efficient and concurrent delivery of data and energy, potentially reducing the need for separate power sources and enhancing the overall efficiency of wireless networks.
2. Network Planning and Deployment:
Deploying infrastructure nodes to maximize covered area per unit of energy, rather than just the area, can significantly reduce energy consumption. Techniques such as base station switch-on/switch-off algorithms and antenna muting adapt to traffic conditions, further enhancing efficiency.
Dense Networks and Small Cells: A mobile network cell includes the antenna, base station and the physical area that is serviced by the cell. A standard cell is called a macro cell. A small cell is just a smaller version of a macro cell and is available in several sizes and powers: micro cells, pico cells and femtocells. Small cells are either installed inside buildings or outside in densely-populated areas. In the case of small cells, the Small Cell Forum predicts that 5G small-cell deployments will overtake 4G small cells by 2024, with the total installed base of 5G or multimode small cells in 2025 to be 13.1 million, constituting more than one-third of the total small cells in use. When you deploy more small cells, the total energy consumption of a network will grow.
However, the energy consumption in a small cell is much lower than in a conventional cell. Moreover, the power required to communicate between clients and 5G base stations increases the further the signal has to be transmitted. Since small cell base stations are deployed in close proximity to client devices, it significantly reduces power consumption by both the base stations and the 5G client devices. Although the total energy consumption increases with more cells, the energy per communication decreases, leading to overall gains in efficiency.
This trade-off has been analyzed, where it is shown that densification has a beneficial impact on energy efficiency, but the gain saturates as the density of the infrastructure nodes increases, thus indicating that an optimal density level exists.
Massive MIMO Antennas:
Massive MIMO systems, an advanced version of MIMO (Multiple-Input Multiple-Output) technology, significantly enhance network capacity by utilizing arrays with hundreds of antennas at each base station. These systems are capable of handling large volumes of network traffic and supporting numerous client connections simultaneously. Although the increased number of hardware components in 5G base stations due to massive MIMO may initially lead to higher energy consumption compared to 4G, the technology’s energy efficiency is expected to improve over time as it evolves.
For example, while a 5G antenna may currently consume three times more energy than a 4G antenna, it is also expected to handle five times the bandwidth and deliver significantly higher throughput, serving more users simultaneously. As the technology matures, energy consumption is anticipated to decrease further, with a potential reduction of up to 25% compared to current levels.
Small cells with massive MIMO antennas can serve many more devices at the same time. Each device is multiplexed over the same space and frequency. This spatial multiplexing uses the same channel to serve multiple devices. The energy consumption is also shared among multiple users or devices. As an example, when 10 devices are multiplexed, the energy consumption of each device is one-tenth, or an energy efficiency of 10x.
Massive MIMO antennas feature an ultra-integrated design, with power amplifiers, radiating elements, and beam management electronics concentrated within the radome. While early implementations may not be fully optimized, ongoing advancements in component integration and densification are expected to reduce energy consumption significantly. One of the key advantages of massive MIMO is its ability to use beamforming, a technique that directs radio signals precisely towards client devices, enhancing channel efficiency, data rates, and reducing interference. This focused transmission also enables the calculation of the minimum power needed for communication, which decreases energy consumption for both the base station and client devices.
For mmWave communications, which involve a large number of antenna elements, digital beamforming can be complex and energy-intensive. Hybrid analog and digital beamforming structures offer a practical solution to mitigate these challenges, reducing both complexity and energy consumption.
Dynamic Network Management
Dynamic network management techniques are being developed to optimize the energy use of 5G networks. These techniques involve adjusting network resources in real-time based on traffic demand. For example, during periods of low usage, certain network elements can be put into a low-power or sleep mode, reducing energy consumption. Similarly, intelligent load balancing can distribute traffic more efficiently across the network, ensuring that resources are used optimally and energy waste is minimized.
Resource Allocation: From a physical standpoint, the efficiency with which a system uses a given resource, is the ratio between the benefit obtained by using the resource, and the corresponding incurred cost. Applying this general definition to communication over a wireless link, the cost is represented by the amount of consumed energy, which includes the radiated energy, the energy loss due to the use of non-ideal power amplifiers, as well as the static energy dissipated in all other hardware blocks of the system (e.g. signal up and downconversion, frequency synthesizer, filtering operations, digital-to-analog and analogto-digital conversion, and cooling operations). Maximizing energy efficiency often requires a trade-off with throughput. By optimizing radio resource allocation for energy efficiency, rather than just throughput, substantial gains can be achieved, albeit with a moderate reduction in data rates.
Base Station Energy Consumption and Cell Switch-Off Techniques
Base stations (BS) are divided into several components: antenna interface, power amplifier, RF chains, baseband unit, mains power supply, and DC-DC supply. Notably, up to 57% of a BS’s power consumption is attributed to the power amplifier and antenna interface, which handle transmission.
Sleep Modes
5G technology introduces advanced sleep modes to enhance energy efficiency. Unlike 4G, which had limited sleep mode capabilities due to constant reference signal transmissions, 5G allows for more sophisticated sleep modes by creating transmission-free time slots during periods of low traffic. This enables base stations to enter sleep mode during brief idle periods, ranging from 5 to 100 milliseconds. Despite high data throughput and reduced packet latency in 5G networks, which increase idle times, these new sleep modes significantly reduce energy consumption. Research indicates that 5G’s ultra-lean design can cut energy use by up to 90% during idle periods compared to current systems, offering a major improvement in energy efficiency.
Cloud-based Radio Access Networks (Cloud RAN) represent a transformative approach to enhancing the energy efficiency of 5G networks. Research from Ericsson highlights that a significant portion of energy consumption in mobile networks is attributable to the RAN and base station sites. By adopting Cloud RAN, which offloads baseband processing and resource allocation to centralized data centers, the network becomes more flexible and cost-efficient. This setup allows for the use of lighter base stations, which only handle radio frequency (RF) and baseband-to-RF conversion, while all complex processing occurs remotely. This architecture not only reduces deployment and operational costs but also leads to substantial energy savings.
Network Virtualization: NFV and SDN
The shift towards Network Functions Virtualization (NFV) and Software Defined Networking (SDN) is crucial for optimizing 5G network efficiency. Traditionally, network infrastructures relied on physical appliances that were rigid and costly to manage. NFV enables the virtualization of network functions such as routing and security, making them more flexible and scalable. SDN complements this by abstracting physical networks into virtual structures, enhancing management and scalability. Together, NFV and SDN minimize computational redundancy and hardware requirements, resulting in lower energy consumption and more efficient network operations.
Visible Light Communications (VLC)
Visible Light Communications (VLC), or LiFi, offers a high-energy efficiency alternative for indoor communications. VLC uses light-emitting diodes (LEDs) to transmit data, providing substantial bandwidth and high data rates. Demonstrations have shown VLC capabilities of up to 3.5 Gbit/s at 2 meters and 1.1 Gbit/s at 10 meters. This technology leverages the visible light spectrum to deliver fast, efficient, and secure data communication.
New Network Protocols
5G introduces new network protocols designed to reduce power consumption significantly. Data packet payload compression lowers traffic volume, while the separation of user and control traffic minimizes network overhead. These changes lead to longer idle periods and extended sleep modes for base stations, reducing overall energy use. Protocols like Multipath Transmission Control Protocol (MPTCP) further enhance efficiency by improving network reliability and reducing the need for packet retransmissions.
Full Duplex
Full-duplex communication represents a leap forward in network efficiency by enabling simultaneous data transmission and reception on the same frequency. Unlike older technologies requiring separate frequencies, full-duplex systems with passive suppression and digital cancellation (PSDC) modes achieve up to 40% greater energy efficiency compared to half-duplex systems. This advancement reduces energy consumption while maintaining high communication throughput.
Cognitive Radio
Cognitive Radio (CR) represents a paradigm shift in achieving energy-efficient communications. By integrating intelligence into radio operations, CR enables dynamic spectrum management and interference mitigation. This approach supports sustainable development by making networks more adaptable and energy-efficient through continuous learning and decision-making processes.
Offloading Techniques:
Offloading techniques are crucial for enhancing the capacity and energy efficiency of 5G networks. Modern user devices are equipped with various radio access technologies (RATs) such as cellular, Bluetooth, and Wi-Fi. When alternative connection options are available, particularly in indoor environments, cellular traffic can be offloaded to these alternatives. This process alleviates the load on cellular networks, freeing up resources for users who rely solely on cellular connections. As 5G networks evolve, offloading strategies will expand beyond Wi-Fi, incorporating a broader range of technologies to optimize network performance and efficiency.
Device-to-device (D2D) communications
Device-to-device (D2D) communications represent a significant advancement over conventional network setups where user devices communicate solely through base stations. In D2D communications, devices in close proximity can transmit data directly using cellular frequencies, under the coordination of the base station (BS). This approach enhances system energy efficiency, as direct communication between nearby devices typically requires much lower transmit power compared to sending data through a distant base station. Furthermore, D2D communications serve as an effective offloading strategy by freeing up base station resources. Through sophisticated interference management, these resources can be reallocated to support other users, thereby optimizing overall network performance.
3. AI and Machine Learning for Energy Optimization
Artificial intelligence (AI) and machine learning (ML) are playing a pivotal role in the quest for greener 5G networks. AI-driven algorithms can analyze vast amounts of data in real-time to identify patterns and make predictive adjustments to network operations. This can include optimizing power consumption, predicting network congestion, and dynamically adjusting the network’s configuration to maintain energy efficiency without compromising performance. By leveraging AI and ML, networks can become more adaptive and responsive, significantly reducing their energy footprint.
Machine learning plays a pivotal role in advancing energy efficiency in wireless networks. Algorithms help in intelligent resource allocation and network reconfiguration, optimizing data rates and reducing energy consumption. By predicting network hot spots and adjusting resources accordingly, machine learning enhances operational efficiency and mitigates interference, leading to significant energy savings.
4. Green Base Stations and Renewable Energy Integration
Another promising development is the integration of renewable energy sources into 5G infrastructure. Green base stations, which utilize solar panels, wind turbines, or other renewable sources, are being deployed to reduce reliance on traditional power grids. These stations are designed to be self-sufficient, generating the energy they need to operate. Additionally, energy storage solutions, such as advanced batteries, are being used to store excess energy generated during peak times for use during periods of low production.
5. Network Slicing for Energy Efficiency
Network slicing is a key feature of 5G that allows multiple virtual networks to be created on a single physical infrastructure. This enables the allocation of network resources to be tailored to specific use cases, ensuring that energy is not wasted on unnecessary capacity. For example, low-latency applications like autonomous driving can be allocated more resources, while less demanding applications can use fewer resources, optimizing energy consumption across the network.
Successful Implementation Case Studies
- Telefónica’s Energy-Efficient Network: Telefónica has implemented a range of energy-saving measures across its network, including optimizing base station power consumption, integrating renewable energy sources, and deploying energy-efficient equipment. These initiatives have led to significant reductions in the company’s overall energy usage.
- Vodafone’s Green Network Initiative: Vodafone has made substantial progress in reducing energy consumption through network optimization, the deployment of energy-efficient hardware, and the integration of renewable energy into its operations. This initiative is part of Vodafone’s broader commitment to achieving net-zero carbon emissions.
- China Mobile’s Green 5G Network: China Mobile has invested heavily in energy-efficient technologies, such as massive MIMO and network slicing, to build a greener 5G network. These efforts have enabled the company to reduce its environmental impact while expanding its 5G coverage across China.
- At MWC Barcelona 2024, Huawei won the GSMA GLOMO ‘Best Mobile Technology Breakthrough’ award for its “0 Bit 0 Watt” solution, a recognition of its innovative energy-efficient network technology.
This solution, designed for energy efficiency without compromising user experience, is the first to win this award. It reduces power consumption to less than 10 watts during idle times and automatically wakes up when needed. The technology optimizes resource and power scheduling based on network load, achieving significant energy savings while maintaining high performance. Deployed in over 30 networks globally, it has reduced daily energy consumption by 9% to 38%. Huawei’s success highlights its commitment to green growth and innovation in the 5G era.
The technologies involved in Huawei’s “0 Bit 0 Watt” solution include:
- Native-Green Network Technology: This refers to the built-in energy-efficient design of the network infrastructure, aiming to minimize power consumption across various components, from equipment to the entire network.
- Deep Sleep Mode for RF Equipment: The solution allows radio frequency (RF) equipment to enter a deep sleep mode during zero-load hours, reducing power consumption to less than 10 watts. The equipment can quickly wake up when needed, ensuring readiness for user service requests.
- Power Amplifier and Antenna Innovations: Huawei has developed advanced power amplifiers and antennas that enhance energy efficiency by optimizing how power is used during different load conditions. These components are crucial for maintaining high performance while reducing energy consumption.
- Intelligent Resource and Power Scheduling: The solution uses AI-driven algorithms to dynamically allocate network resources based on service types and network load. This ensures that energy is used efficiently, distributing it where it’s needed most while conserving it elsewhere.
- Load-Sensing Technology at Network Sites: Network sites equipped with this solution can sense changes in equipment load and adjust power feeding and storage accordingly. This capability allows for real-time adjustments to maximize energy efficiency at the site level.
- End-to-End High Energy Efficiency: The solution integrates energy-saving measures across the entire network, from the hardware level (power amplifiers, antennas) to software-driven network management. This holistic approach ensures that every aspect of the network contributes to reduced energy consumption.
These technologies work together to create a highly efficient and responsive network infrastructure that minimizes energy use while maintaining a high-quality user experience, particularly in the context of expanding 5G networks.
The Path Forward: Balancing Performance with Sustainability
As the world embraces 5G, the challenge of energy efficiency cannot be overlooked. While 5G networks offer tremendous benefits, their success depends on our ability to manage their energy demands sustainably. The technologies and strategies mentioned above represent just a few of the ways the industry is addressing this issue. By continuing to innovate and prioritize energy efficiency, we can ensure that the next generation of connectivity is not only fast and reliable but also sustainable.
In the years to come, the balance between performance and sustainability will be a key determinant of 5G’s long-term success. By investing in green communications and networking technologies today, we can pave the way for a more connected and environmentally responsible future.
References and Resources also include
https://www.huawei.com/en/news/2024/2/0bit0watt-technology-glomo
