6G Technology Challenges, Innovations and Prospects
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This post was last edited by qwqwqw2088 on 2020-8-5 08:52
6G network refers to the mobile communication network that will be commercially available in 2030. The development of mobile communication networks from 1980 to 2020 has witnessed the "glorious decade" in which 3G mobile users surpassed fixed users, experienced the "wonderful decade" in which 4G mobile Internet changed lives, and opened the "innovative decade" in which 5G Internet of Everything changed society. In the future "innovative decade", 5G commercial networks will continue to evolve in terms of services and network technologies, and eventually transition to 6G networks; therefore, 6G is also the long-term evolution network of 5G.
■ Current status of 6G global research
With the successful large-scale commercial use of 5G networks, global industry, academia and research have officially launched research on 6G's potential service needs, network architecture and potential enabling technologies in 2019.
■ 1.1 European Union
NetWorld2020, the EU enterprise technology platform, released the white paper "Intelligent Networks in the Next Generation Internet" in September 2018. On this basis, the EU will formulate the 6G Strategic Research and Innovation Agenda (SRIA) and Strategic Development Technology (SDA) under the 2021-2027 Industry-University-Research Framework Project in the third quarter of 2020, and formally establish the EU 6G Partner Cooperation Project at the Mobile World Congress in the first quarter of 2021, and start the first batch of 6G Intelligent Network Service Industry-University-Research Framework Project in April 2021.
■ 1.2 Finland 6G flagship project
In May 2018, the Finnish government took the lead in establishing the 6G flagship project led by the University of Oulu, Finland. The project members are mainly Finnish companies, universities and research institutes. The project plans to invest 2.51 billion euros in 6G research and development from 2018 to 2026. The University of Oulu in Finland takes the lead in organizing two 6G wireless summits in March every year. Major manufacturers and operators have delivered speeches at the 6G Technology Summit, and released the white paper "Drivers and Main Research Challenges for 6G Ubiquitous Wireless Intelligence" in September 2019 based on technical discussions at the meeting.
Currently, the 6G Wireless Summit is drafting 6G technology white papers on 12 technical topics, and will release several technical white papers as early as the second half of 2020, including 6G drive and UN sustainable development goals, vertical service verification and testing, wireless communication machine learning, B5G networking, broadband connection, radio frequency (RF) technology and spectrum, remote area connection, 6G business, 6G edge computing, trust security and privacy, 6G critical and large-scale machine communications, positioning and sensing.
■ 1.3 United States
The Federal Communications Commission (FCC) of the United States launched a study on new terahertz spectrum services in the frequency range of 95 GHz to 3 THz in 2018, and began issuing 10-year trial spectrum licenses for saleable network services in June 2019. The main issues of its spectrum research include: 1) the government and non-government share the use of the 95-275 GHz frequency band; 2) 275 GHz to 3 THz does not interfere with the use of existing spectrum; 3) the unlicensed spectrum has a total bandwidth of 21.2 GHz, including 116-123 GHz, 174.8-182 GHz, 185-190 GHz, and 244-246 GHz.
The Alliance for Telecommunications Industry Solutions (ATIS) released a 6G Action Plan on May 19, 2020, suggesting that the government invest additional R&D funds in 6G core technology breakthroughs and encourage the government and enterprises to actively participate in the formulation of national spectrum policies. At present, the future 5G and 6G core technologies that the United States hopes to dominate include 5G Integrated and Open Networks (ION), advanced networks and services that support artificial intelligence (AI), advanced antennas and radio systems (such as terahertz bands above 95 GHz), multi-access network services (including ground and non-ground networks, self-sensing to support applications such as ultra-high-definition positioning), smart healthcare network services (including remote diagnosis and surgery, using new features such as multi-sensing applications, tactile Internet and ultra-high-resolution 3D imaging) and Agriculture 4.0 services (supporting the unified application of water, fertilizers and pesticides).
■ 1.4 Japan and South Korea
The Japanese government will release a 6G wireless communication network research strategy in the summer of 2020. The South Korean government's Electronics and Telecommunications Research Institute (ETRI) signed a 6G network cooperation research agreement with the University of Oulu in Finland in June 2019; Samsung has focused on 6G, artificial intelligence and robotics since 2019; LG established a 6G research center in cooperation with the Korea Institute of Science and Technology (KAIST) in January 2019; SKT and manufacturers jointly studied 6G key performance indicators and business needs.
■ 1.5 China
China's Ministry of Industry and Information Technology took the lead in establishing a 6G Promotion Group in June 2019 (including five working groups: demand, spectrum, network, wireless technology, standards and international cooperation) to carry out feasibility studies on 6G standards and plans to complete the research and verification of 6G services, vision and enabling technologies from 2019 to 2023.
In November 2019, the Ministry of Science and Technology of China took the lead in launching a 6G Technology R&D Promotion Group, which is participated by 37 industry, academia and research institutions, to carry out industry-university-research cooperation projects on 6G requirements, structure and enabling technologies.
■ 1.6 Others
China Mobile released the "6G Vision and Requirements" and white paper in November 2019, and Japan's DoCoMo released the "B5G and 6G Wireless Technology Requirements" white paper in January 2020. Driven by some industry-university-research institutions, the International Telecommunication Union's standardization department (ITU-T) established a research project on 6G requirements and network structure, namely the IMT-2030 Focus Group, in 2018. The research project has successively released white papers or technical research reports such as "6G Technology Blueprint, Applications and Market Drivers", "6G New Services and Network Technology Service Capabilities" and "Representative Use Cases and Key Network Requirements".
■ 2. 6G research and standardization work roadmap forecast
The forecast of 6G standard work roadmap of ITU, China 6G Promotion Group and 3GPP in the next 10 years is shown in Figure 1. The corresponding basic judgment is:
1) 2020-2023 is the feasibility study window for 6G services, vision, and enabling technologies;
2) 2020 is the early stage of identifying 6G enabling technologies.
The WP5D working group of the International Telecommunication Union Radiocommunication Sector (ITU-R) plans to complete the research report on "Future Technology Trends of IMT" in June 2022[1-2] and the research report on "IMT-2020 Vision" between June 2021 and November 2022. It is expected that the World Radiocommunication Conference (WRC) at the end of 2023 will discuss the spectrum requirements for 6G, and the WRC at the end of 2027 will complete the 6G spectrum allocation.
The research and verification of 6G services, vision and enabling technologies by China's IMT-2030 and 6G Promotion Group will be synchronized with the ITU-R's 6G standard work plan. It is predicted that China will complete the research, testing and system trials of 6G systems and spectrum between 2023 and 2027.
Towards ITU 2028-2029
3GPP expects to formally launch the feasibility study of 6G standard requirements, structure and air interface technology in the 2024-2025 R19 window, and complete the formulation of 6G air interface standard technical specifications as early as 2026-2027, the R20 window. Prior to this, 3GPP will complete the formulation of 5G evolution standards for R17 and R18 in 2020-2023. This stage can be referred to as post-5G or B5G standards. The main functions of R17/18 5G evolution standards include evolved air interfaces and enhanced functions for future use cases such as evolved mobile broadband, fixed wireless access, industrial Internet of Things, Internet of Vehicles, extended reality, massive machine communications, drone and satellite access, such as 5G high-frequency band air interface, namely NR 52.6-71 GHz, 5G non-terrestrial network air interface (NR-NTN) and its high-frequency band NTN, cellular narrowband IoT non-terrestrial network (NB-IoT/eMTC-NTN), 5G mid-range capability air interface and its evolution function (NR-RedCap+) for mid-range terminals such as wearables and video surveillance, 5G multimedia broadcast and multicast service air interface and its evolution function (NR-MBMS+), access and backhaul integrated evolution function (IAB+), 5G direct transmission air interface and its evolution function (NR-Sidelink+), 5G unlicensed frequency band air interface and its evolution function (NR-U+), positioning enhancement function, intelligent self-organizing network and its evolution function, communication sensor integration and its evolution function (ICS+), network topology enhancement function, etc.
+: Evolution or enhancement
IAB: Access and Postback Integration
ICS: Communication and Sensing Integration
ITU-R: International Telecommunication Union Radiocommunication Sector
MBMS: Multimedia Broadcast and Multicast Service
NB-IoT/eMTC-NTN: Cellular narrowband physical network serving non-terrestrial networks
NR: 5G air interface
NR-RedCap: 5G mid-range capability air interface
NR-Sidelink: 5G direct transmission service air interface
NR-U: 5G unlicensed frequency band air interface
NTN: Non-Terrestrial Network
SON: Self-Organizing Network
WRC: World Radiocommunication Conference
Figure 1 B5G/6G research and standardization work roadmap forecast
■ 3. 6G business drivers and vision
The convenient consumption of upstream traffic of user-defined videos (such as TikTok), the widespread application of machine vision computing (such as face recognition), the potential consumption of extended reality (XR), light field and point cloud and other light wave holographic transmission, the emergence of zero-distance virtual on-site interaction (such as remote "real person" duets or band "cloud performances"), the dexterous and reliable digital human/motorcycle/robot terminal cluster (such as self-driving cars) services, and the gradual implementation of the United Nations 2030 Sustainable Development Goals [1], all indicate the business development trend of humanization, holographic interaction, and group collaboration.
The rapid development and application of 4G and 5G, IoT, cloud-edge computing, artificial intelligence (AI) and machine learning (ML) [3-5], big data, blockchain, satellite rockets, drones, wearable technology, robotics, implantable technology, and super-silicon computing and communication technology have laid a solid technical foundation for business innovation. Driven by the dual innovation of applications and technology, 5G applications will grow rapidly in the next 10 years and create new lifestyles, digital economies, and social structures, such as cross-class digital life, Internet celebrity economy, and digital aristocracy.
In order to adapt to the business development trend of humanization, holographic interaction and group collaboration, the new services that may be born in the 6G era will be further expanded to the perception Internet, AI service Internet and industry service Internet, presenting the 6G vision of Wanwu Zhilian to change the world, see Figure 2 for details.
AR: Augmented Reality
VR: Virtual Reality
AI: Artificial Intelligence
CPS: Cyber-Physical Systems
ML: Machine Learning
XR: Extended Reality
Figure 2 6G service development trends and vision
■ 4. Preliminary analysis of 6G service requirements
4.1 Perception Internet
The perceptual Internet refers to holographic collaborative real-time interactive media interconnection services such as vision, hearing, touch, taste, smell, emotion and thought.
A typical use case of the perception Internet is "real-time shared perception" which means that within a predetermined duration, after permission and trust control, a person can truly experience the feelings and even life of another person through his or her own vision and other senses. For example, a mother can truly experience whether her child's feet are rubbed after wearing new shoes.
4.2 AI Serving the Internet
AI service Internet refers to the collaborative intelligent interconnected services that any person, machine, organization or behavior can enjoy in the future.
A typical use case of AI serving the Internet is "autonomous driving on highways", which means that an unmanned car or fleet of cars uses the best route design of the real-time navigation and positioning robot to intelligently avoid collisions with people or objects outside the car, and reach the destination in the shortest time and with the least energy consumption.
4.3 Industry Service Internet
The Industry Service Internet refers to the collaborative or virtual twin sensing and execution interconnected services required across any domain or platform, any cyber-physical system (CPS) or digital twin service.
A typical use case of the industry service Internet, "tactile feedback robotic surgery", refers to the remote completion of non-invasive surgical operations such as coronary artery and laparoscopy through human-machine collaboration and with the help of multi-channel auxiliary videos [including augmented reality (AR) videos] and tactile feedback.
4.4 6G Service Requirements
The perception Internet focuses on real-time sharing of perception holograms, the AI service Internet focuses on ubiquitous intelligence, and the industry service Internet focuses on collaborative automation between humans and machines.
Figure 3 lists the preliminary connection requirements for the above typical use cases, including but not limited to bandwidth, latency, synchronization, jitter, reliability, high-precision positioning, energy consumption, computing power, biocompatibility, etc. The specific performance indicators of each typical use case are still under study.
AI: Artificial Intelligence, CPS: Cyber-Physical Systems
Figure 3 Perception, AI and industry service Internet use cases and requirements
■ 5. Preliminary prediction of 6G network performance indicators
Based on the results of the 3GPP R17 5G new service requirements study [6-13], combined with the requirements for high-definition, high-degree-of-freedom, human-eye-limit video bandwidth and reliability [14-15], as well as the requirements for autonomous driving positioning accuracy [16] and non-ground network aerial base station mobile speed [17], we can preliminarily estimate the performance indicator requirements for new services in the 6G era and the improvement multiples relative to 5G network performance indicators, as shown in Figure 4.
The 6G network will support a peak data rate of 1 Tbit/s, a user experience data rate of 20 Gbit/s, a regional service capacity density of 10 Gbit/(sm2), a spatial capacity density of 100 Gbit/(sm3), a connection density of 100 terminals per square meter, a maximum coupling loss of 167 dB (indicating the extreme coverage range), a base station or cell moving speed of 8 km/s, a user plane latency of less than 0.5 ms, a reliability of more than 7 nines, a battery life of 20 years, a deterministic communication delay synchronization accuracy of 0.2μs, and a high-precision positioning accuracy of less than 10 cm.
Since 5G networks support 20 Gbit/s peak data rate, 100 Mbit/s user experience data rate, 10 Mbit/(sm2) regional service capacity density, 1 terminal connection density per square meter, 164 dB maximum coupling loss (indicating the limit coverage), 500 km/s mobile speed, 0.5 ms eMBB user plane (UP) one-way delay, 5 9s reliability, 10-year battery life, 1μs deterministic communication time synchronization accuracy, and more than 10m positioning accuracy, the performance indicators of 6G compared to 5G networks are improved by multiples, as shown in Figure 4. Of course, with the continuous expansion of 5G service use cases, 5G long-term evolution networks can also gradually meet these network performance indicator requirements.
Figure 4 6G network performance index requirements and their improvement multiples relative to 5G
■ 6. Potential enabling technologies for 6G networks
In view of the above-mentioned 6G and 5G long-term evolution network service and performance requirements, and referring to the global industry-university-research B5G/6G technology research results, 6G network enabling technology can be considered from the six dimensions of structure, link, airspace, watershed, reasoning, and computing as shown in Figure 5, specifically including autonomous automatic networks, intelligent three-dimensional connections, intelligent large-scale antenna arrays, on-demand network topology, on-demand network computing, and super-silicon computing and communications.
AI: Artificial Intelligence CPS: Cyber Physics
IoT: Internet of Things
MIMO: Multiple Input Multiple Output
NR: 5G air interface
NTN: Non-Terrestrial Network
Figure 5 6G network technology system framework
6.1 Autonomous Network Architecture
6G networks not only need to support intelligent, automated, and service-oriented system network architectures to achieve software-defined intelligence, orchestration, and management (such as cognitive networks, service architectures, fully automatic lifecycle management, CPS, and digital twin networks), but also need to support wireless network architectures that include smart radio, smart coverage, and smart evolution [18] to ensure the flexibility and software programmability of connection elements such as services, orchestration, management, topology, deployment, coverage, air interfaces, and antennas.
The so-called smart radio refers to a software-defined wireless channel, which achieves wireless connection with wired communication quality or better by separating the wireless link from its propagation characteristics; smart coverage refers to the separation of terminals and cells, virtual cells serve terminals, and cell edges no longer exist; smart evolution refers to the evolution of independent wireless network functions, any dynamic operation can support AI processing, and the network topology can be flexibly selected and changed according to service requirements. Therefore, the 6G autonomous network architecture will become the basis for the integration of various 6G network enabling technologies.
6.2 Intelligent 3D Connection
Intelligent three-dimensional connection refers to integrated full-band intelligent communication connection in the air, sky, land and sea, supporting human-to-human communication, human-machine cooperative communication and machine communication, supporting the frequency range from MHz to THz, and supporting the integrated networking of 2G/3G/4G/5G and other ground networks (TN) and non-ground networks (NTN) - here NTN refers to non-ground communication networks composed of ground/underwater drones, semi-stationary aerial platforms, aircraft, low/medium/high/synchronous earth orbit satellites, etc.
The main technical challenges of intelligent three-dimensional connection include: full-band spectrum management, including NR/IoT-NTN air interface evolution, communication and sensor integration, THz and visible light communication, centimeter-level high-precision positioning and other multi-standard air interface designs, multi-standard harmonious physical layer coexistence design, long-distance random access and time-frequency offset compensation technology, high-spectrum efficiency large-connection multiple access technology, wireless resource and interference management, high-speed mobility management, business and terminal service continuity, determinism and its communication technology, especially intelligent connection strategies that meet one or a group of specific business requirements (such as spectrum efficiency, energy efficiency, cost efficiency, reliability, latency and jitter).
Among them, the challenges of terahertz communication technology include: extremely low peak-to-average power ratio waveform and modulation, ultra-large bandwidth and capacity channel coding, extremely narrow beam management technology, diffuse scattering channel modeling technology, extremely low power consumption RF devices, high-gain antenna technology, large bandwidth digital-to-analog and analog-to-digital conversion technology, all-electric and optoelectronic hybrid link design, etc. The challenges of visible light communication technology include: design of optical signal sources such as visible light superluminescent diodes, large bandwidth and high-sensitivity optical detectors, external modulators, amplifiers, multiplexing and demultiplexing, optical switches and transceiver integrators and other optoelectronic hybrid devices, indoor/outdoor/underwater optical channel modeling and array antenna technology
6.3 Intelligent Large-Scale Antenna Array
Intelligent large-scale antenna array refers to intelligent antenna array technology that achieves the optimal design requirements of three-dimensional connection links based on spatial freedom, including energy-efficient large-capacity multi-user MIMO (MU-MIMO) technology, ultra-large-scale antenna array intelligent beam management technology, terminal-centric distributed MIMO technology, and flexibly deployed intelligent reflection/transmission surface technology.
Its main application scenarios include high-frequency coverage in densely populated urban areas, large-capacity MU-MIMO energy efficiency improvement, outdoor to indoor continuous coverage, high-frequency band high-speed mobile lossless switching, and artificial wireless channel environments.
Its main technical challenges include joint optimization of spatial efficiency and link performance, design of high-gain and low-loss intelligent antenna panels, flexible deployment strategy of network-level multi-antennas, design of intelligent MIMO algorithms, and optimization design of intelligent pilots and training sequences.
6.4 On-demand network topology
On-demand network topology refers to the flexible selection or change of network deployment form and density based on service and connection requirements, including TN/NTN access and backhaul integration, local mesh network, flexible multicast and multi-hop technology, dynamic path selection, dynamic network slicing, multi-layer heterogeneous densification technology, etc., to achieve on-demand optimization of performance indicators such as cost and energy consumption.
Its main application scenarios include cross-industry (such as satellite broadcasting and communications) digital infrastructure comprehensive service platforms, locally deployed CPS or digital twins and other deterministic sensor communication (such as digital twin city infrastructure monitoring, collaborative robot communication) service platforms.
Its main technical challenges include data/intent-driven intelligent topology [including mesh, multicast, multi-hop] strategies, flexible wireless access networks or virtual cells (i.e., user-centric service cells), intelligent mobile networks (including user or site mobility prediction and switching), and intelligent end-to-end network slicing (including business and user resource demand prediction and allocation).
6.5 On-demand network computing
On-demand network computing refers to 6G network intelligent agents, computing power and algorithm technologies, including deep learning algorithms such as neural networks, reinforcement learning, transfer learning, adversarial learning, federated learning, automatic learning, explainable learning, responsible learning, as well as global and local AI layering technologies and AI air interface design and AI chip technologies to ensure service, resource, management, especially computing power efficiency and its trustworthiness.
Its application scenarios include automatic modulation and demodulation of the physical layer and channel coding and decoding, wireless high-precision positioning, mobility management, flexible network deployment, network service orchestration and management, etc.
Its main technical challenges include cloud-edge hybrid federated AI architecture, network global and local AI integration, target alignment of multiple AI agents, design of explainable AI algorithms, self-service acquisition of labeled data, active learning of data labels, and reduction of training and testing errors.
6.6 Super Silicon Computing and Communications
Beyond silicon computing and communication refers to various post-Moore computing or brain-inspired computing technologies[19], including computing storage technology, neuromorphic computing, quantum computing and other new computing technologies, computing technologies based on new two-dimensional/three-dimensional materials such as graphene and carbon nanotubes, three-dimensional heterogeneous integration, multi-chip structures and high-speed interconnection technologies, as well as ambient wireless energy harvesting technology, extremely close human wireless communication or liquid molecular communication, and human brain-computer or cloud interface technology.
Of course, the feasibility of these new computing technologies may need to be considered in the framework of the 6G evolution network, such as microscopic three-dimensional connection technologies represented by molecular communication[20] (chemical communication of liquids or their sprays) and brain-cloud interface[21] (the interface between neuronal cell synapses and the super brain cloud).
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提升卡
变色卡
千斤顶
Good information, with technical content, looking forward to 6G