Content for TR 36.872 Word version: 12.1.0
2 References
3 Definitions and abbreviations
4 Small cell scenarios for evaluation
5 Potential enhancements to improve spectrum efficiency
6 Mechanisms to ensure efficient operation of a small cell layer
7 Physical layer study for small cell enhancements higher-layer aspects
A Simulation model
$ Change History
2 References p. 6
3 Definitions and abbreviations p. 7
3.1 Definitions p. 7
3.2 Abbreviations p. 7
4 Small cell scenarios for evaluation p. 7
5 Potential enhancements to improve spectrum efficiency p. 12
5.1 Introduction of a higher order modulation scheme for the downlink p. 12
5.2 Enhancements and overhead reduction for UE-specific reference signals and control signalling p. 19
6 Mechanisms to ensure efficient operation of a small cell layer p. 24
6.1 Mechanisms for interference avoidance and coordination among small cells p. 24
6.1.1 Small cell on/off p. 24
6.1.1.1 Small cell on/off schemes and performance gains p. 24
6.1.1.1.1 Semi-static small cell on/off schemes and performance gains p. 24
6.1.1.1.2 Ideal, dynamic small cell on/off schemes and performance gains p. 38
6.1.1.1.3 NCT with reduced CRS and performance gains p. 43
6.1.1.2 Small cell on/off energy saving p. 44
6.1.1.3 Time scales for on/off transitions p. 46
6.1.1.3.1 Feasible time scales based on legacy procedures p. 46
6.1.1.3.2 Feasible time scales enhancements p. 47
6.1.1.4 Potential impacts on network performance other than throughputs p. 47
6.1.1.5 Standards impacts for enhancements p. 47
6.1.1.6 Conclusions p. 47
6.1.2 Enhanced power control/adaptation p. 48
6.1.3 Enhancement of frequency domain power control and/or ABS to multi-cell scenarios p. 48
6.1.3.1 Enhancement of (e)ICIC to multi-cell scenarios for small cell deployments p. 48
6.1.3.2 Enhancement of EPDCCH for small cell deployments p. 49
6.1.4 Load balancing/shifting p. 49
6.2 Mechanisms for efficient discovery of small cells and their configurations p. 50
6.2.1 Performance evaluation p. 50
6.2.1.1 Rel-8 mechanism p. 50
6.2.1.2 PSS/SSS interference canceller-based mechanism p. 52
6.2.1.3 Other RS-based mechanisms (with existing RS) p. 54
6.2.1.4 Modified SS/RS or new discovery signal-based mechanism p. 56
6.2.1.5 Evaluation on opportunistic activation and deactivation of small cells based on UL signals p. 57
6.2.1.6 Additional observation related to inter-frequency small cell discovery p. 57
6.2.2 Enhancements of small cell discovery p. 58
6.2.2.1 PSS/SSS interference cancellation p. 58
6.2.2.2 Burst transmission of DL-SS/RS p. 58
6.2.2.3 Network synchronization and assistance p. 58
6.2.2.4 New discovery mechanism p. 58
6.2.2.5 Transmission of DL-SS/RS at specific carrier p. 59
6.2.2.6 Relaxed RAN4 requirement p. 59
6.2.2.7 Specification impacts p. 59
6.2.3 Necessity of PCI extension p. 60
6.2.4 Summary on small cell discovery p. 60
6.3 Feasibility and benefits of radio-interface based synchronization mechanisms p. 61
6.3.1 Network listening p. 62
6.3.1.1 Introduction of network listening p. 62
6.3.1.2 Review of the standard work of network listening schemes p. 62
6.3.1.3 Achievable synchronization accuracy p. 62
6.3.1.4 Network listening period configuration p. 63
6.3.1.5 Resource overhead p. 63
6.3.1.6 Applicability/compatibility with the ongoing studies p. 63
6.3.1.7 Support of inter-operator synchronization p. 63
6.3.1.8 Cost and complexity p. 63
6.3.1.9 Standards impacts p. 63
6.3.1.10 Performance evaluation p. 64
6.3.2 UE-assisted synchronization p. 70
6.3.2.1 Achievable synchronization accuracy p. 70
6.3.2.2 Resource overhead p. 70
6.3.2.3 Applicability/compatibility with the ongoing studies p. 70
6.3.2.4 Support of inter-operator synchronization p. 70
6.3.2.5 Standards impacts p. 70
6.3.3 Summary p. 71
7 Physical layer study for small cell enhancements higher-layer aspects p. 72
A Simulation model p. 73
A.1 General evaluation assumptions p. 73
A.1.1 Scenario 1 p. 73
A.1.2 Scenario 2a p. 76
A.1.3 Scenario 2b (sparse) p. 78
A.1.4 Scenario 2b (dense) p. 83
A.1.5 Scenario 3 (sparse) p. 88
A.1.6 Scenario 3 (dense) p. 91
A.2 Uplink specific evaluation parameters p. 94
A.3 Evaluation assumptions for spectrum efficiency enhancements p. 95
A.4 Evaluation assumptions for efficient operation p. 97
$ Change History p. 100
