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  • ReceivedMay 17, 2020
  • AcceptedJun 17, 2020
  • PublishedNov 24, 2020

Abstract


Acknowledgment

This work was supported by National Key RD Program of China (Grant No. 2018YFB1801101), National Natural Science Foundation of China (Grant Nos. 61960206006, 61901109), Frontiers Science Center for Mobile Information Communication and Security, High Level Innovation and Entrepreneurial Research Team Program in Jiangsu, High Level Innovation and Entrepreneurial Talent Introduction Program in Jiangsu, National Postdoctoral Program for Innovative Talents (Grant No. BX20180062), Research Fund of National Mobile Communications Research Laboratory, Southeast University (Grant No. 2020B01), and Fundamental Research Funds for the Central Universities (Grant No. 2242020R30001).


Supplement

Appendix


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  • Figure 1

    (Color online) A vision of 6G wireless communication networks.

  • Figure 2

    (Color online) An overview of 6G wireless communication networks.

  • Figure 3

    (Color online) Organization of this paper.

  • Figure 4

    (Color online) Performance metrics of 6G communication networks.

  • Figure 5

    (Color online) Application scenarios of 6G communication networks.

  • Figure 6

    (Color online) Comparison of 5G and 6G requirements of key performance metrics and application scenarios.

  • Figure 7

    (Color online) Cloud VR reference architecture[17].

  • Figure 8

    ICDT-based C-V2X architecture.

  • Figure 9

    (Color online) The schematic of the digital twin body area network to help manage the epidemic.

  • Figure 10

    (Color online) The connection between traditional mobile communications and micro-mobile communications in body, body surface, and body domain [39].

  • Figure 11

    OTFS Tx and Rx.

  • Figure 12

    Parallel concatenated encoder and decoder [93].

  • Figure 13

    Serially concatenated encoder and decoder.

  • Figure 14

    Three-stage serially concatenated encoder and decoder.

  • Figure 15

    (Color online) An illustration of blockchain-based networks.

  • Figure 16

    (Color online) Concepts of direct O/T and T/O conversion.

  • Figure 17

    (Color online) A high-level overview of SDN architecture [171].

  • Figure 18

    (Color online) A high-level overview of NFV architecture [175].

  • Figure 19

    (Color online) Network slicing conceptual outline [183].

  • Figure 20

    SBA for 5G core network [188].

  • Figure 21

    (Color online) An illustration of DEN$^2$.

  • Figure 22

    (Color online) CF massive MIMO system model.

  • Figure 23

    (Color online) SDN-based CF architecture [201].

  • Figure 24

    (Color online) Multi-tier computing network architecture, which integrates cloud, edge, and fog computing technologies to enable intelligent services for anything at anytime and anywhere [216].

  • Figure 25

    (Color online) Integration of terrestrial and satellite communication networks.

  • Figure 26

    (Color online) Maritime MTC network functional view and topology for service-centric and software-defined networking [244].

  • Figure 27

    (Color online) International frequency allocations for maritime MTC [243,246].

  • Figure 28

    (Color online) Space-air-ground-sea integrated network control architecture.

  • Figure 29

    (Color online) Microphotograph of the multiplier with on-chip antenna.

  • Figure 30

    (Color online) (a) SNR of a COTS red LED at a distance of 1.6 m and bit loading pattern. Binary phase shift keying (BPSK) is still achieved between 900 MHz–1 GHz which is well above the 3-dB bandwidth of the device. (b) Channel gains of the different colors (red, green, blue, and yellow) of the wavelength division multiplexing (WDM) system which achieved 15.7 Gbps with COTS LEDs [287].

  • Figure 31

    (Color online) Underwater communication system using micro LEDs [302].

  • Figure 32

    (Color online) DL-aided Bayesian optimal estimators for physical layer communications.

  • Figure 33

    The framework of 5G network optimization based on DRL with the help of physical model.

  • Figure 34

    (Color online) An illustration of virtual vehicular networks.

  • Figure 35

    (Color online) The self-evolution closed-loop structure of the intelligence-endogenous network.

  • Table A1  

    Table A1A list of abbreviations

    Abbreviation Definition Abbreviation Definition
    2D two-dimensional MBD mobile big data
    3D three-dimensional MCS modulation coding scheme
    3GPP 3rd generation partnership project MEC mobile edge computing
    4G fourth generation MIMO multiple-input multiple-output
    5G fifth generation ML machine learning
    5G-ACIA 5G alliance for connected industries and automation MLSE maximum likelihood sequence estimation
    5G PPP 5G infrastructure public private partnership MMSE minimum mean squared error
    6G sixth generation mMTC massive machine type communications
    ACK acknowledgment mmWave millimeter wave
    A-CPI application-controller plane interface MPC multipath component
    A/D analog-to-digital MR maximum ratio
    AI artificial intelligence MRC maximum ratio combining
    AMF access and mobility management function MRT maximum ratio transmission
    ANN artificial neural network MS mobile station
    AP access point MTC machine type communication
    AR augmented reality MUST multi-user superposition transmission
    ASK amplitude shift keying MZM Mach-Zehnder modulator
    AUSF authentication server function NAS non-access stratum
    BB baseband NEF network exposure function
    BCH Bose-Chaudhuri-Hocquenghem NFV network functions virtualization
    BCJR Bahl, Cocke, Jelinek, and Raviv NFVI NFV infrastructure
    BER bit error rate NFV M&O NFV management and orchestration
    BPF bandpass filter NGMN next-generation mobile network
    B-RAN blockchain radio access network NG-RAN next-generation radio access network
    BS base stations NLOS non-line-of-sight
    BSS business support system NOMA non-orthogonal multiple access
    CC central controller NP non-deterministic polynomial
    CF cell-free NR new radio
    CGM continuous glucose monitoring NRF network function repository function
    CIR channel impulse response NR-V new radio vehicle
    CNN convolutional neural network NWDA network data analytics
    CoMP coordinated multi-point OAM orbital angular momentum
    COTS commercial off-the-shelf OFDM orthogonal frequency-division multiplexing
    CPM continuous phase modulation OMA orthogonal multiple access
    CPU central processing units ONF open networking foundation
    CR cognitive radio O-RAN open radio access network
    CRC cyclic redundancy check OSS operations support system
    CSA cognitive service architecture OTFS orthogonal time frequency space
    CSI channel state information OWC optical wireless communication
    CT computed tomography P2P peer-to-peer
    C-V2X cellular vehicle to everything PAPR peak to average power ratio
    D/A digital-to-analog PCC parallel concatenated codes
    DAS distributed antenna system PCF policy control function
    D-CPI data-controller plane interface PDA placement delivery array
    DEN$^2$ deep edge node and network PDF probability density function
    DetNet deterministic networking PDP power delay profile
    DL deep learning PLS physical layer security
    DN data network PSD power spectral density
    DNN deep neural network QAM quadrature amplitude modulation
    DOF degree of freedom Q-D quasi-deterministic
    DRL deep reinforcement learning QKD quantum key distribution
    (To be continued on the next page
  • Table 1  

    Table 1Industrial use cases and requirements[26]

    Use case (high level) Availability Cycle time Typical payload # of Typical service area
    (%) (ms) size devices
    Motion control Printing machine textgreater99.9999 textless 2 20 bytes textgreater100 100 m$\times$100 m$\times$30 m
    Machine tool textgreater99.9999 textless 0.5 50 bytes $\sim$20 15 m$\times$15 m$\times$3 m
    Packaging machine textgreater99.9999 textless 1 40 bytes $\sim$50 10 m$\times$5 m$\times$3 m
    Mobile robots
    Cooperative motion control
    textgreater99.9999 1 40–250 bytes 100 $<$ 1 km$^2$
    Video operated
    remote control
    textgreater99.9999 10–100 15–150000 bytes 100 $<$ 1 km$^2$
    Mobile control Assembly robots or textgreater99.9999 4–8 40–250 bytes 4 10 m$\times$10 m
    panels with milling machines
    safety functions Mobile cranes textgreater99.9999 12 40–250 bytes 2 40 m$\times$60 m
    Process automation (process monitoring) textgreater99.99 textgreater 50 Varies 10000 devices per km$^2$
  •   
    (Continued
    Abbreviation Definition Abbreviation Definition
    EAP extensible authentication protocol QoE quality of experience
    ECG electrocardiogram QoS quality of service
    EEG electroencephalogram QSDC quantum secure direct communication
    EIRP effective isotropic radiated power RAN radio access network
    eMBB enhanced mobile broadband RAU remote antenna unit
    EMG electromyogram RF radio frequency
    EMS element management system RMS root mean square
    ETSI European telecommunication standards institute RSC radio side controller
    euRLLC enhanced-uRLLC RSS received signal strength
    EXIT extrinsic information transfer RTT round trip time
    FBMC filter bank multi-carrier Rx receiver
    FCC federal communications commission RZF regularized zero-forcing
    FDD frequency division duplex SBA service-based architecture
    FDMA frequency division multiple access SC successive cancellation
    FEC forward error correction SCC serially concatenated code
    FSO free space optical SCM spatial channel model
    FTTA fiber-to-the-antenna SCMA sparse code multiple access
    GBSM geometry-based stochastic model SDN software defined network
    GFDM generalized frequency division multiplexing SFFT symplectic finite Fourier transform
    GPS global positioning system SGS satellite ground station
    HA horn antenna SIMO single-input multiple-output
    HAP high altitude platform SINR signal-to-interference-plus-noise ratio
    HARQ hybrid automatic repeat request SISO single-input single-output
    HCC hybrid concatenated codes SLC satellite local controller
    HD high definition SMF session management function
    HST high-speed train SNR signal-to-noise ratio
    IC integrated circuits SR symbiotic radio
    ICDT information, communication, and data technology S-V Saleh-Valenzuela
    ICI inter-carrier interference TCP transmission control protocol
    ICT information and communication technology TDD time division duplex
    IEN intelligence endogenous network TLC terrestrial local controller
    IETF Internet engineering task force THz terahertz
    ILDP interactive learning design paradigm ToF THz-over-fiber
    IoE Internet of everything TSAP terrestrial-satellite access point
    IoT Internet of things Tx transmitter
    IP Internet protocol UAV unmanned aerial vehicle
    IRS intelligent reflection surface UDM unfied data management
    ISFFT inverse symplectic finite Fourier transform UDN ultra-dense network
    ISM industrial, scientific, and medical UE user equipment
    IT information technology uHDD ultra-high data density
    ITS intelligent transportation system uHSLLC ultra-high-speed with low-latency
    ITU international telecommunication union communications
    KPI key performance indicator uMUB ubiquitous mobile ultra-broadband
    LAP low altitude platform UPF user plane function
    LDPC low-density parity-check code uRLLC ultra-reliable and low latency communications
    LED light emitting diode UTC-PD uni-traveling-carrier photodiode
    LEO low Earth orbit UV ultraviolet
    LO local oscillator V2V vehicle-to-vehicle
    LOS line of sight V2X vehicle to everything
    LTE long term evolution VHF very high frequency
    LTE-LAA LTE license assisted access VLC visible light communication
    LTE-U LTE unlicensed VNF virtualized network function
    LTE-V long time evolution vehicle VR virtual reality
    MAC media access control XR extended reality
    MAEC multi-access edge computing ZF zero forcing