International telecommunication union

1 Scope 3

2 References 3

3 Definitions 3

3.1 Terms defined elsewhere 3

3.2 Terms defined in this document 6

4 Abbreviations and acronyms 6

5 Conventions 9

6 Executive Summary 9

7 Gap analysis and recommendations to Study Group 13 14

7.1 High-level Architecture 14

7.1.1 Standardization gaps for the IMT-2020 high-level architecture 14

7.1.2 Recommendations to parent group on High-level Architecture 19

7.2 Network Softwarization 19

7.2.1 Standardization gaps on Network softwarization 19

7.2.2 Recommendations to parent group on network softwarization 28

7.3 End-to-end QoS 28

7.3.1 Standardization gaps on end-to-end QoS 28

7.3.2 Recommendations to parent group on End-to-end QoS 31

7.4 Mobile front haul and back haul 31

7.4.1 Standardization gaps on Mobile front haul and back haul 31

7.4.2 Recommendations to parent group on Mobile front haul and back haul 36

7.5 Emerging Network Technologies 37

7.5.1 Standardization gaps on Emerging Network Technologies 37

7.5.2 Recommendations to parent group on Emerging Network Technologies 42

8 Conclusion and future work 43

Bibliography 44

Appendix I 48

High-level network architecture for IMT-2020 48

1Scope 48

2References 48

3Terms and definitions 49

4Abbreviations and acronyms 50

5IMT-2020 use cases 50

5.1Smart Grid 51

5.2E-Health 51

5.3Autonomous car 53

5.4Internet of things 53

6Performance targets for IMT-2020 54

7Requirements and gap analysis 55

7.1Enhanced mobile broadband services 55

7.2Enhanced massive machine type communications 56

7.3Ultra-reliable and low latency communications 56

7.4Flexibility and programmability 56

7.5Quality of service 57

7.6Energy efficiency 57

7.7Enhanced privacy and security 57

7.8Multiple heterogeneous radio access networks 57

7.9Fixed-mobile convergence 57

7.10Operation and management 58

8Structuring of IMT-2020 requirements 59

8.1Access network-agnostic and unified core network 59

8.2Distributed network architecture 60

8.3Integrated management of multi-RAT and fixed access networks 60

8.4Flexible signaling 60

8.5Latency optimized network 60

8.6Extensible network 60

9High-level IMT-2020 network architecture 61

9.1IMT-2020 network architecture 61

9.2Functional elements in IMT-2020 network architecture 62

9.2.1Data plane functions 62

9.2.2Control plane functions 62

9.3IMT-2020 interworking scenarios with legacy IMT networks 63

10Contributors (in Alphabetical Order) 64

Acknowledgement 64

Appendix II 66

Network Softwarization for IMT-2020 networks 66

1 Scope 67

2 References 67

3 Terms defined in this report 69

3.1 Terms defined elsewhere 69

3.2 Terms defined in this recommendation 71

4 Abbreviations and acronyms 71

5 Conventions 71

6 Network softwarization 71

6.1 Motivations 71

6.2 Relevant use cases 72

6.2.1 Support of various applications 72

6.2.2 Use of ICN for Inter-function transport 73

6.2.3 Use of ICN function state migration 74

6.2.4 ICN removes host endpoint abstraction from application data 75

6.3 Overview of network softwarization 76

6.4 Characteristics of network softwarization 76

6.5 Requirements for 5G specific network 77

6.6 Network softwarization in 5G mobile networks 78

6.6.1 Network softwarization 78

6.6.2 Horizontal extension of slicing 80

6.6.2.1 End-to-end slicing 80

6.6.2.2 End-to-end latency breakdown and programmability consideration 80

6.6.3 Vertical extension of slicing (Data plane enhancement) 82

6.6.3.1 Deep data plane programmability 82

6.6.4 Considerations for applicability of softwarization 82

6.6.5 End-to-end reference model for scalable operation 83

6.6.6 Coordinated APIs 84

6.7 Energy management aspects of network softwarization 86

6.8 Economic incentives aspects of network softwarization 87

7 Integrated network management and orchestration 87

8 Mobile edge computing 89

8.1 General description 89

8.2 Use cases and scenarios 90

8.2.1 Augmented reality 90

8.2.2 Data analytics 90

8.2.3 Mobile video delivery optimization using throughput guidance for TCP 91

8.3 Key challenges 91

8.3.1 Virtualization 92

8.3.2 Mobility 92

8.3.3 Simple and controllable APIs 92

8.3.4 Application lifecycle management 92

8.3.5 Platform service management 92

8.3.6 Traffic routing 92

8.3.7 Data forwarding to edge or conventional computing server 93

8.3.8 Control signal transfer management 93

8.3.9 Inter-edge mobility 93

9 Distributed cloud for service providers 94

9.1 Introduction 94

9.2 Key characteristics 95

10 In-network data processing 96

11 Resource usage optimization 97

12 Resource abstraction 98

13 Migration towards newly emerging networks 99

14 RAN virtualization and slicing under software control 100

15 Capability exposure 104

15.1 Architecture 104

16 Identification of gaps 105

Appendix III 115

End-to-end QoS 115

1Scope 116

2References 117

3Terms and Definitions 117

4Abbreviations and acronyms 117

5Review of perspectives and standards on IMT-2020 118

5.1Survey of Whitepapers 118

5.2Gap Analysis of Standards on IMT-2020 121

5.2.1Definition of “End-to-End” in different standards 121

5.2.2Layered Approach for QoS Management 122

5.2.3QoS Classification 122

5.3Rationale for a common QoS framework for IMT-2020 123

6Network performance, Quality of Service and Quality of Experience 123

7Top down perspective of QoS 125

8Reference model of Connectivity 126

9Layered model of performance 128

10QoE parameters 129

10.1Selecting QoS Parameters from different standards 130

10.1.1ITU-T Y.1540, Y.1541 130

10.1.23GPP TS 23.107, 3GPP TS 23.203, 3GPP TS 23.401 130

10.2Approach for defining new parameters 131

11QoS classes and their performance objectives 132

12Allocation guidance 132

12.1Methods for QoS Budget Allocation 132

12.1.1Static Approach 132

12.1.2Pseudo-static Approach 133

12.1.3Signalled Approach 133

12.1.4Impairment accumulation Approach 133

12.1.5Need for a new approach 133

13 Examples of end-to-end connectivity over wireless and wireline networks 135

Editor’s note: This clause was originally indicated as an appendix in the draft output from the end-to-end QoS group. 135

13.1 International Voice Call 135

13.2 Domestic Video Telephony 135

13.3 Telecommunication services for Emergency/Disaster Relief 136

Appendix IV 138

Mobile front haul and back haul 138

1.Scope 138

2.References 138

3 Terminology Definitions 139

3.1 Backhaul refers to the network paths connecting the Base Station sites and the Network Controller/ Gateway sites. 139

3.2Fronthaul refers to the intra-base-station transport, in which a part of the BS function is separated to the remote antenna site. (Note that this definition is equivalent to the definition given in [MEF 22.1.1] for the current 4G technology.) 139

4 Abbreviations and acronyms 139

6 Future Use Cases and Technology Drivers 142

6.1Large capacity 142

6.2 Low latency 143

6.3 Power saving 143

6.4 Large-scale disaster/congestion/failure resilience 143

6.5 Diversified types of terminal/traffic/operator 143

7.Technical Challenges 144

7.1 Transport bandwidth 144

7.2 Functional split 145

7.3 Network Timing and synchronization 145

7.4 Power efficiency of fronthaul 147

7.5 Large number of small cells 149

7.6 Reliability and resilience 151

7.7 Diversified types of terminal/traffic/operator/FH&BH 152

7.8 Support of network slicing / management with FH&BH 154

8. Architecture and Solutions for Mobile Fronthaul 156

8.1 Digital Radio (CPRI) over optical fiber 156

8.2Analog Radio over optical fiber (P2P and PON) 157

8.3Digital Radio (CPRI) over optical transport (OTN) 157

8.4New digital format replacing CPRI 158

8.5Radio over Packet 158

8.6Function Splitting in MFH 159

8.7Reuse of existing access networks 159

8.7.18. x Digital Radio (CPRI) over metro WDM (G.metro) 160

9Solutions for Mobile Backhaul 160

9.1Network timing and synchronization in MBH 160

9.2Energy saving methods in MBH 161

Appendix V 163

Emerging Network Technologies 163

1 Scope 163

2 References 163

3 Definitions 164

4 Abbreviations and acronyms 164

5 Conventions 164

6 Motivation for Information Centric Networking 164

6.1 Overview of ICN 164

7 Use Cases 169

7.1 ICN- IoT 169

8 Relationship/Coexistence with Mobile edge computing 177

8.1 ICN Mobile Edge Computing 177

9 Relationship/Coexistence with Network Slicing 179

9.1 Use of ICN for Inter-function transport 179

9.2 Use of ICN function state migration 180

9.3 Use of ICN for de-abstracting the network 181

10 Identification of gaps 182

11 Migration from the existing network technology 183