Content for TR 23.700-25 Word version: 18.1.0
5 Key Issues
6 Solutions
7 Evaluation
8 Conclusions
A KI#1 related additional analysis
$ Change history
5 Key Issues p. 11
5.1 Key Issue #1: 5GS network timing synchronization status and reporting p. 11
5.1.1 Description p. 11
5.2 Key Issue #2: Time synchronization service enhancements p. 11
5.2.1 Description p. 11
5.3 Key Issue #3: Support for controlling 5G time synchronization service based on subscription p. 12
5.3.1 Description p. 12
5.4 Key Issue #4: How to enable an AF to explicitly provide PER to NEF/PCF p. 12
5.4.1 Description p. 12
5.5 Key Issue #5: Interworking with TSN network deployed in the transport network p. 12
5.5.1 Description p. 12
5.6 Key Issue #6: Adapting downstream scheduling based on RAN feedback for low latency communication p. 13
5.6.1 Description p. 13
6 Solutions p. 13
6.0 Mapping of Solutions to Key Issues p. 13
6.1 Solution #1: Inform UE and AF about network timing synchronization status p. 14
6.1.1 Introduction p. 14
6.1.2 Functional Description p. 14
6.1.3 Procedures p. 17
6.1.4 Impacts on services, entities and interfaces p. 17
6.2 Solution #2: Burst arrival time adaptation p. 17
6.2.1 Introduction p. 17
6.2.2 Functional Description p. 17
6.2.3 Procedures p. 18
6.2.4 Impacts on services, entities and interfaces p. 18
6.3 Solution #3: Timing synchronization resiliency and status reporting p. 19
6.3.1 Introduction p. 19
6.3.2 Functional Description p. 19
6.3.3 Procedures p. 20
6.3.4 Impacts on services, entities and interfaces p. 21
6.4 Solution #4: 5GC learning and reporting network timing synchronization status p. 21
6.4.1 Introduction p. 21
6.4.2 Functional Description p. 22
6.4.2.1 Functional Description for 5GC learning network timing synchronization status p. 22
6.4.2.2 Functional Description for network timing synchronization status information p. 23
6.4.2.3 Functional Description for AF requested network timing synchronization status p. 23
6.4.2.4 Functional Description for network timing synchronization status reporting to UE(s) p. 25
6.4.3 Procedures p. 25
6.4.3.1 Procedure for AF requested network timing synchronization status p. 25
6.4.3.2 Procedure for UE provisioning network timing synchronization status p. 28
6.4.4 Impacts on services, entities and interfaces p. 30
6.5 Solution #5: Inform UE and AF about 5GS network timing synchronization status for PTP p. 31
6.5.1 Introduction p. 31
6.5.2 Functional Description p. 31
6.5.3 Procedures p. 31
6.5.4 Impacts on services, entities and interfaces p. 31
6.6 Solution #6: Support for 5G Timing Exposure Enhancement. p. 32
6.6.1 Introduction p. 32
6.6.2 General description p. 32
6.6.3 Procedures p. 32
6.6.4 Impacts on services, entities and interfaces p. 34
6.7 Solution #7: RequestedCoverage area filters for time synchronization service p. 34
6.7.1 Introduction p. 34
6.7.2 Functional Description p. 34
6.7.3 Procedures p. 35
6.7.3.1 Procedure for AF requested (g)PTP timing synchronization with Requested Coverage Area p. 35
6.7.3.1a Procedure for AF requested (g)PTP timing synchronization with Requested Coverage Area where UE's presence is obtained via TSCTSF triggered deferred 5GC-MT-LR p. 37
6.7.3.2 Procedure for AF requested 5G access stratum timing synchronization with Requested Coverage Area p. 39
6.7.3.2a Procedure for AF requested 5G access stratum timing synchronization with Requested Coverage Area where UE's presence is obtained via TSCTSF triggered deferred 5GC-MT-LR p. 40
6.7.4 Impacts on services, entities and interfaces p. 42
6.8 Solution #8: AF Request of PER for QoS and Alt-QoS p. 42
6.8.1 Introduction p. 42
6.8.2 Functional Description p. 42
6.8.3 Procedures p. 42
6.8.4 Impacts on services, entities and interfaces p. 43
6.9 Solution #9: Interworking with TSN network deployed in the transport network p. 43
6.9.1 Introduction p. 43
6.9.2 Functional Description p. 44
6.9.3 Procedures p. 47
6.9.4 Impacts on services, entities and interfaces p. 47
6.10 Solution #10: 5GC acting as a CUC for CNC in TN p. 48
6.10.1 Introduction p. 48
6.10.2 Functional Description p. 48
6.10.3 Procedures p. 49
6.10.4 Impacts on services, entities and interfaces p. 51
6.11 Solution #11: Interworking with TSN enabled N3 transport network for deterministic traffic delivery p. 52
6.11.1 Introduction p. 52
6.11.2 Functional Description p. 52
6.11.3 Procedures p. 54
6.11.4 Impacts on services, entities and interfaces p. 55
6.12 Solution #12: Cross layer scheduling optimization based on RAN feedback p. 55
6.12.1 Introduction p. 55
6.12.2 Functional Description p. 55
6.12.3 Procedures p. 56
6.12.4 Impacts on services, entities and interfaces p. 57
6.13 Solution #13: Pro-active RAN burst timing preference provision p. 57
6.13.1 Introduction p. 57
6.13.2 Functional Description p. 57
6.13.3 Procedures p. 58
6.13.4 Impacts on existing services and interfaces p. 59
6.14 Solution #14: Assisted and Complement Timing Support p. 60
6.14.1 General p. 60
6.14.2 Functional Description p. 60
6.14.3 Procedures p. 61
6.14.3.1 Procedures for (g)PTP time distribution p. 61
6.14.3.2 Procedures for 5G access stratum time distribution p. 64
6.14.4 Impacts on services, entities and interfaces p. 67
6.15 Solution #15: Burst arrival time adaptation p. 68
6.15.1 Introduction p. 68
6.15.2 Functional Description p. 68
6.15.3 Procedures p. 68
6.15.4 Impacts on services, entities and interfaces p. 69
6.16 Solution #16: BAT adjustment during a QoS Flow setup or modification p. 69
6.16.1 Introduction p. 69
6.16.2 Functional Description p. 69
6.16.3 Procedures p. 70
6.16.4 Impacts on services, entities and interfaces p. 71
6.17 Solution #17: DS-TT and NW-TT assisted 5GS synchronization error detection p. 71
6.17.1 Introduction p. 71
6.17.2 Functional Description p. 72
6.17.3 Procedures p. 72
6.17.4 Impacts on services, entities and interfaces p. 73
6.18 Solution #18: Subscription based control of time synchronization service p. 73
6.18.1 Introduction p. 73
6.18.2 Functional Description p. 73
6.18.3 Procedures p. 75
6.18.3.1 Procedure for subscription based control of access stratum time synchronization service without AF request p. 75
6.18.3.2 Procedure for subscription based control of access stratum time synchronization service with AF request p. 76
6.18.3.3 Procedure for subscription based control of (g)PTP time synchronization service without AF request p. 77
6.18.3.4 Procedure for (g)PTP time synchronization service with AF request p. 78
6.18.4 Impacts on services, entities and interfaces p. 78
6.19 Solution 19: Support for controlling 5G time synchronization service based on subscription p. 79
6.19.1 Introduction p. 79
6.19.2 General description p. 79
6.19.3 Procedures p. 80
6.19.4 Impacts on services, entities and interfaces p. 81
6.20 Solution #20: NG-RAN acting as CUC towards CNC of the N3 transport network p. 81
6.20.1 Introduction p. 81
6.20.2 Functional Description p. 81
6.20.3 Procedures p. 82
6.20.4 Impacts on services, entities and interfaces p. 82
6.21 Solution #21: BAT adjustment by TSNCF to TSN in the transport network p. 82
6.21.1 Introduction p. 82
6.21.2 Functional Description p. 82
6.21.3 Procedures p. 83
6.21.4 Impacts on services, entities and interfaces p. 84
6.22 Solution #22: Transmission opportunities exposure p. 84
7 Evaluation p. 86
7.1 Key Issue #3: Support for controlling 5G time synchronization service based on subscription p. 86
7.2 Key Issue #5: Interworking with TSN network deployed in the transport network p. 87
7.3 Evaluation for KI #6: Adapting downstream scheduling based on RAN feedback for low latency communication p. 88
8 Conclusions p. 89
8.1 Conclusion for KI #4: AF Request of PER for QoS and Alt-QoS p. 89
8.2 Key Issue #2: Time synchronization service enhancements p. 89
8.3 Conclusion for KI #5: Interworking with TSN network deployed in the transport network p. 90
8.4 Key issue #6: Adapting downstream scheduling based on RAN feedback for low latency communication p. 91
8.5 Conclusion for KI #1: 5GS network timing synchronization status and reporting p. 92
8.6 Conclusion for KI#3: Support for controlling 5G time synchronization service based on subscription p. 95
A KI#1 related additional analysis p. 98
A.1 Methods to notify RAN Time Synchronization Status towards the UE p. 98
$ Change history p. 105
