【爱立信Ericsson】20246G无线接入网RAN能源绩效白皮书十年一遇的机遇_18页_868kb

Energy Performance of 6G Radio Access Networks: A once in a decade opportunity

Core Content

This white paper explores the energy performance of 6G radio access networks (RAN), emphasizing the need for significant improvements in energy efficiency. It highlights that reducing network energy consumption is a critical goal for the 6G era, especially as the energy consumption of cellular networks is dominated by the need to provide area coverage and activate idle-mode user equipment (UE).

The paper discusses the concept of lean design in 6G, building upon the successes of 5G NR. Lean design focuses on minimizing unnecessary transmissions and enabling more efficient power usage by introducing micro-sleep periods in network equipment. It also suggests extending lean design to spatial, frequency, and time domains to further enhance energy savings.

The RAN is identified as the main energy consumer in cellular networks, accounting for approximately 76% of total energy consumption. This is due to the bursty nature of traffic and the fact that most cells are not continuously active. Therefore, energy savings must be targeted at idle-mode operations, which are responsible for a large portion of network energy use.

Main Views

• Lean Design in 5G NR: 5G NR introduced lean design, reducing signaling and enabling micro-sleep, which led to significant energy savings.
• 6G Lean Design: The paper proposes further lean design improvements in 6G, such as:
  • Time Domain: Increasing the periodicity of the idle-mode synchronization signal (SSB) from 20 ms to 160 ms or even longer.
  • Spatial Domain: Using single-frequency-network (SFN) formats and optimizing beam shapes for different functions.
  • Frequency Domain: Allowing for dynamic carrier usage and reducing the need for system-information broadcast on all carriers.
• Separation of Concerns: 6G should separate idle-mode and connected-mode functions by using distinct signals, enabling more efficient and independent optimization of each function.
• Scalable by Design: The RAN should be designed to scale efficiently and adapt quickly to changing traffic demands, ensuring that energy consumption is proportional to actual usage.
• Observability and Adaptability: 6G requires enhanced observability of both network energy consumption and user experience to enable dynamic hardware configuration and real-time energy management.

Key Information

• Energy Savings Potential: By extending idle-mode SSB periodicity to 160 ms, 6G could reduce idle-mode energy consumption by up to 4 times compared to 5G NR.
• Traffic Characteristics: Most data sessions are small, and the network is mostly idle, which presents a significant opportunity for energy savings.
• Network Design Considerations:
  • Centralized RAN Processing: This can reduce the energy consumption by allowing for more efficient resource pooling and coordination.
  • Multi-carrier and Multi-point Support: These features provide additional opportunities for energy optimization.
• UE Compatibility: To ensure the effectiveness of lean design, all UEs should support the new synchronization and signaling features in the first 6G release.
• Adaptability of Hardware: The RAN must dynamically adjust its hardware configurations based on service requirements, such as rate, latency, and priority, to minimize energy use while maintaining performance.

Conclusion

The white paper concludes that 6G presents a unique opportunity to significantly improve network energy performance through lean design, separation of concerns, and fast adaptability. These principles allow for a more efficient use of resources and a reduction in energy consumption, especially during idle periods. Achieving these goals requires careful standardization, observability, and coordination across all network components and functions. The long-term success of 6G depends on the ability to design a system that is energy-efficient, scalable, and adaptable to the evolving demands of the network and users.

References

1. GSMA Intelligence, Going green: measuring the energy efficiency of mobile networks, February 2024.
2. 3GPP, Study on network energy savings for NR (Release 18), TR 38.864.

Authors

• Pål Frenger: Senior expert at Ericsson with over 25 years of experience in RAN energy performance. Specializes in 5G and 6G standardization and development. Holds a Ph.D. in electrical engineering from Chalmers University of Technology.
• Ylva Jading: Senior specialist in network energy performance at Ericsson Research, Stockholm. Has been working at Ericsson since 1999 and leads energy-performance research for future 6G networks. Holds a Ph.D. in physics from Johannes Gutenberg University Mainz.
• Ali Nader: R&D professional at Ericsson with extensive experience in 3GPP-based network access functionalities. Has contributed to the development of NB-IoT and 5G-related features. Since 2018, has been involved in energy performance concept development for both devices and networks.