Tech-invite  3GPPspace  IETFspace
◀  ▶  21  22  23  24  25  26  27  28  29  31  32  33  34  35  36  37  38  4‑5x
Top   in Index   Prev   Next

TR 36.881
Study on Latency Reduction Techniques for LTE

3GPP‑Page
V14.0.0 (Wzip)  2016/06  99 p.
Rapporteur:
Mr. Enbuske, Henrik

full Table of Contents for  TR 36.881  Word version:  14.0.0

1Scope  p. 6
2References  p. 6
3Definitions, symbols and abbreviations  p. 7
3.1Definitions  p. 7
3.2Symbols  p. 7
3.3Abbreviations  p. 8
4Study Objectives  p. 8
5Overview of LTE latency  p. 8
5.1Delay components  p. 8
5.1.1UL and DL latency  p. 8
5.1.2Handover latency [11]  p. 10
5.2Current performance  p. 12
5.2.1UL and DL latency  p. 12
5.2.2Handover latency [11]  p. 13
5.3Existing means to limit latency  p. 14
6Scenarios, Applications and Use Cases  p. 14
7Evaluation Structure and Assumptions  p. 15
8Solutions for latency reduction  p. 15
8.1Semi-Persistent Scheduling  p. 15
8.2UL Grant reception  p. 15
8.2.1Configured SPS activation and deactivation  p. 15
8.3Handover Latency  p. 16
8.3.1Solution 1: RACH-less handover  p. 16
8.3.2Solution 2: Maintaining Source eNB Connection during Handover  p. 17
8.4Contention based PUSCH transmission  p. 18
8.4.1Solution 1 [16]  p. 18
8.4.2Solution 2 [17]  p. 18
8.5Reduced TTI and processing time  p. 19
9Performance Evaluation  p. 20
9.1Protocol evaluations on TTI reduction and Fast UL  p. 20
9.1.1Simulation 1: TCP slow-start behavior for FTP file download based on reduced TTI and reduced SR periodicity [4]  p. 21
9.1.2Simulation 2: Capacity and throughput gain with 0.5ms TTI [5]  p. 24
9.1.3Simulation 3: Throughput and packet download time with reduced latency in LTE [3]  p. 26
9.1.4Simulation 4: Latency evaluation results for TTI reduction and Fast UL [6]  p. 27
9.1.4.1Simulation assumptions  p. 27
9.1.4.2TTI shortening simulations  p. 28
9.1.4.3Fast UL system simulations  p. 30
9.1.5Simulation 5: System Performance with TTI shortening [6]  p. 34
9.1.5.1General information  p. 34
9.1.5.2Simulation assumptions and parameters  p. 35
9.1.5.3Performance results  p. 35
9.1.5.3.1Various backhaul latency  p. 35
9.1.5.3.2Various FTP file size  p. 37
9.1.5.3.3Various Uu throughput  p. 39
9.1.5.3.4Fast UL access  p. 42
9.1.6Simulation 6: Evaluation results for TTI reduction [6]  p. 44
9.1.6.1Simulation assumptions  p. 44
9.1.7Simulation 7: Performance evaluation of latency reduction enhancements [6]  p. 46
9.1.7.1Simulation setup  p. 46
9.1.7.2Simulated schemes  p. 47
9.1.7.3Simulation results for shorter TTI  p. 48
9.1.7.4Simulation results for Fast UL grant with shorter TTI  p. 50
9.1.8Simulation 8: TTI reduction gain with additional L1/L2 overhead [6]  p. 52
9.1.8.1Simulation assumptions  p. 52
9.1.8.2Evaluation results  p. 53
9.1.9Simulation 9: Effect of UE and eNB processing times on TCP performance [6]  p. 54
9.1.9.1Simulation assumptions  p. 55
9.1.9.2Evaluation results  p. 55
9.1.10Simulation 10: System Performance Gain with TTI reduction [6]  p. 58
9.1.10.1Faster UE Feedback and Rate Control  p. 58
9.1.10.2Simulation Assumptions:  p. 59
9.1.10.3Simulation Results  p. 59
9.1.11Simulation 11: TTI reduction gain with additional L2 overhead [9]  p. 60
9.1.11.1Simulation assumptions  p. 60
9.1.11.2Evaluation results  p. 60
9.1.12Simulation 12: TTI reduction gain with additional L2 overhead [10]  p. 61
9.1.12.1Simulation assumptions  p. 61
9.1.12.2Evaluation results  p. 62
9.2Protocol evaluations on Contention based PUSCH transmission  p. 64
9.2.1Evaluation 1 on solution 1 [16]  p. 64
9.2.1.1Resource efficiency  p. 64
9.2.1.2Uplink latency  p. 65
9.2.2Evaluation on solution 2 [17]  p. 66
9.2.2.1Resource efficiency analysis on current solutions  p. 66
9.2.2.2Uplink latency  p. 67
9.2.2.3Resource efficiency  p. 69
9.2.3Evaluation 2 on solution 1 [18]  p. 70
9.3Handover latency [11]  p. 74
9.4Findings from system evaluations on TTI reduction and reduced processing time  p. 74
9.5Findings from link evaluations on TTI reduction and reduced processing time  p. 76
9.5.1sPDSCH  p. 76
9.5.2sPDCCH  p. 76
9.5.3sPUSCH  p. 77
9.5.4sPUCCH  p. 77
10Conclusion  p. 77
10.1RAN2 Protocol Evaluations  p. 77
10.2RAN1 Shortened TTI and reduced processing time  p. 78
ASimulation assumptions  p. 79
A.1Protocol Simulations  p. 79
A.1.1Simulation 1 [4]  p. 79
A.1.2Simulation 2 [5]  p. 81
A.1.3Simulation 4 [6]  p. 82
A.1.4Simulation 9 [6]  p. 83
A.1.5Simulation 5 [6]  p. 85
A.1.6Simulation 11 [9]  p. 87
A.1.7Simulation on contention based PUSCH transmission  p. 90
A.2System simulation assumptions for reduced TTI and processing delay  p. 92
A.2.1Evaluation assumption for TDD  p. 93
A.3Link level simulation assumptions  p. 95
BSystem evaluation results  p. 98
CLink-level evaluation results  p. 98
$Change History  p. 98

Top