Towards 6G wireless communication networks:vision, enabling technologies, and new paradigm shifts
- Science China(Information Sciences) 2021年01期
The fifth generation（5G） wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability,and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation（6G） wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle（UAV） communication networks, thus achieving a space-airground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6GHz, millimeter wave（mmWave）, terahertz（THz）,and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence（AI） and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
1 Introduction 2 Performance metrics,application scenarios,and example industry verticals 2.1 Performance metrics and application scenarios 2.2 Example industry verticals 2.2.1 Cloud VR 2.2.2 IoT industry automation 2.2.3 C-V2X 2.2.4 Digital twin body area network 2.2.5 Energy efficient wireless network control and federated learning systems 3 Enabling technologies 3.1 Air interface and transmission technologies 3.1.1 New waveforms 3.1.2 Multiple access 3.1.3 Channel coding 3.1.4 CF massive MIMO 3.1.5 Dynamic and intelligent spectrum sharing and accessing 3.1.6 Blockchain-based wireless accessing and networking 3.1.7 Photonics defined radio 3.1.8 MCo for uRLLC 3.2 Network architecture 3.2.1 SDN/NFV 3.2.2 Network slicing and its improvement 3.2.3 SBA and its evolution 3.2.4 CSA 3.2.5 DEN2 3.2.6 CF architecture 3.2.7 Cloud/fog/edge computing 4 New paradigm shifts 4.1 Global coverage:space-air-ground-sea integrated networks 4.1.1 Satellite communication network 4.1.2 UAV communication network 4.1.3 Maritime machine-type communication network 4.1.4 Space-air-ground-sea integrated networks 4.2 All spectra:sub-6 GHz,mmWave,THz,and optical frequency bands 4.2.1 Sub-6 GHz bands 4.2.2 mmWave bands 4.2.3 THz bands 4.2.4 Optical frequency bands 4.2.5 Channel measurements and models for 5G and beyond 4.3 Full applications:AI enabled wireless networks 4.3.1 AI and ML technologies:an overview 4.3.2 Physical layer applications 4.3.3 Upper layer applications 4.3.4 Resource allocation applications 4.3.5 Intelligence endogenous networks （IENs） 4.3.6 Toward ICDT convergence in 6G 4.4 Endogenous network security 4.4.1 Current status and main issues 4.4.2 Network security concerns in 6G 4.4.3 Possible countermeasures to the security and privacy issues in 6G networks 5 Conclusion Appendix A