Contents

Acknowledgments

Forewords

Gordon Mansfield

Small Cell Forum

Alan Stidwell

Orange Labs, France Telecom

Preface

Contributors

Acronyms

1 Introduction

1.1 Mobile data explosion and capacity needs

1.2 Capacity and coverage solutions

1.2.1 Improving existing macrocell networks

1.2.2 Network base station densification

1.2.3 Indoor capacity and coverage

1.2.4 Heterogeneous cellular networks

1.3 Heterogeneous cellular network nodes

1.3.1 Remote radio heads

1.3.2 Micro base stations

1.3.3 Pico base stations

1.3.4 Femtocell access points

1.3.5 Relay nodes

1.4 3GPP LTE-Advanced heterogeneous cellular networks

1.5 Heterogeneous cellular network challenges

1.5.1 Optimal network evolution path

1.5.2 Access control

1.5.3 Mobility and handover

1.5.4 Self-organizing networks

1.5.5 Intercell interference

1.5.6 Intersite coordination

1.5.7 Energy efficiency

1.5.8 Backhaul

References

2 Radio propagation modeling

2.1 Introduction

2.2 Different types of propagation model

2.2.1 Empirical models

2.2.2 Deterministic models

2.2.3 Semi-deterministic models

2.2.4 Hybrid models

2.3 Clutter and terrain

2.4 Antenna radiation pattern

2.5 Calibration

2.6 MIMO channel models

2.6.1 Geometry-based stochastic channel models

2.6.2 3GPP SCM and WINNER I model

2.6.3 WINNER II model

2.6.4 COST 259/273/2100 MIMO channel models

2.6.5 Perspectives of channel modeling

2.7 Summary and conclusions

References

3 System-level simulation and evaluation models

3.1 Introduction

3.2 System-level simulation

3.3 Static versus dynamic system-level simulations

3.3.1 Static snapshot-based approaches

3.3.2 Dynamic event-driven approaches

3.4 Building blocks

3.4.1 Wrap-around

3.4.2 Shadow fading: auto- and cross-correlation

3.4.3 Multi-path fading: International Telecommunication Union (ITU) andTypical Urban (TU) models

3.4.4 Antenna patterns

3.4.5 Signal quality: maximal ratio combining (MRC) and exponentialeffective SINR mapping (EESM)

3.5 3GPP reference system deployments and evaluation assumptions

3.5.1 Homogeneous deployments

3.5.2 Heterogeneous deployments

3.6 Placing of low-power nodes and users

3.6.1 Macrocells overlaid with indoor or outdoor picocells or relays

3.6.2 Macrocells overlaid with indoor femtocells

3.7 Traffic modeling

3.7.1 Full buffer model

3.7.2 FTP model

3.7.3 VoIP model

3.8 Mobility modeling

3.9 Summary and conclusions

Copyright notices

References

4 Access mechanisms

4.1 Introduction

4.2 Access control modes

4.3 Basics of the UMTS cellular architecture

4.3.1 Core network

4.3.2 Access network

4.3.3 Radio protocol functions in UTRAN

4.4 Basics of the LTE cellular architecture

4.4.1 Evolved Packet Core (EPC)

4.4.2 Access network

4.4.3 Radio protocol functions in Evolved-UTRAN (E-UTRAN)

4.5 LTE Release 8: mobility management to CSG cells

4.5.1 Idle mode mobility to and from CSG cells

4.5.2 Mobility to and from CSG cells in RRCCONNECTED mode

4.5.3 PCI confusion

4.6 LTE Release 9: mobility enhancements to CSG cells andintroduction of HA cells

4.6.1 Hybrid access

4.6.2 Access control, PCI confusion resolution and proximity indication

4.7 LTE Release 10 and beyond: introduction of X2 interface for HeNBs

4.8 Distinguishing features of UMTS access mechanisms

4.9 Case study of access control in LTE

4.9.1 Open access heterogeneous cellular network

4.9.2 Closed access heterogeneous cellular network

4.10 Conclusions

Copyright notices

References

5 Interference modeling and spectrum allocation in two-tier networks

5.1 Introduction

5.2 Interference modeling

5.3 System model

5.3.1 Two-tier network model

5.3.2 Spectrum allocation

5.3.3 Femtocell access

5.3.4 Signal-to-interference ratio

5.4 Downlink success probability

5.4.1 Success probabilities with closed access femtocells

5.4.2 Success probability with open access femtocells

5.5 Two-tier downlink throughput optimization

5.5.1 Downlink throughput analysis

5.5.2 Network throughput optimization

5.5.3 Optimal joint allocation with closed access femtocells

5.5.4 Optimal disjoint allocation with closed access femtocells

5.5.5 Optimal joint allocation with open access femtocells

5.5.6 Optimal disjoint allocation with open access femtocells

5.6 Numerical results

5.7 Conclusion and future direction

5.8 Appendix

5.8.1 Derivation of fR(r)

5.8.2 Proof of Lemma 5.1

5.8.3 Proof of Lemma 5.2

5.8.4 Proof of Lemma 5.4

5.8.5 Proof of Lemma 5.5

Copyright notice

References

6 Self-organization

6.1 Introduction

6.2 Management architecture

6.3 Self-configuration

6.3.1 Planning

6.3.2 Installation

6.4 Self-optimization

6.4.1 Automatic neighbor relation

6.4.2 Automatic cell identity management

6.4.3 Random access optimization

6.4.4 Mobility robustness optimization

6.4.5 Mobility load balancing

6.4.6 Transmission power tuning

6.4.7 Coverage and capacity optimization

6.5 Self-healing

6.6 Performance monitoring

6.6.1 Minimization of drive tests

6.6.2 Heterogeneous cellular network monitoring

6.7 Summary and conclusions

References

7 Dynamic interference management

7.1 Excessive intercell interference

7.1.1 Transmission power difference between nodes

7.1.2 Low-power node range expansion

7.1.3 Closed subscriber group access

7.2 Range expansion

7.2.1 Definition of range expansion

7.2.2 Downlink/uplink coverage imbalance

7.2.3 Behavior of range expansion

7.3 Intercell interference coordination

7.4 Frequency-domain intercell interference coordination

7.4.1 Frequency-domain intercell interference coordination in LTE

7.4.2 Carrier-based intercell interference coordination

7.4.3 Uplink interferer identification

7.5 Power-based intercell interference coordination

7.5.1 Uplink power-based intercell interference coordination

7.5.2 Downlink power-based intercell interference coordination

7.6 Time-domain intercell interference coordination

7.6.1 Almost blank subframes

7.6.2 Almost blank subframes for range-expanded picocells

7.6.3 Reduced-power subframes and UE interference cancellation

7.7 Performance evaluations

7.7.1 Power-based and time-domain intercell interference coordination

7.7.2 Performance analysis for time-domain intercell interference coordination

7.7.3 Coverage analysis for time-domain intercell interferencecoordination and range expansion

7.7.4 Capacity analysis for time-domain intercell interferencecoordination and range expansion

7.7.5 Reduced-power ABS and UE interference cancellation

7.8 Summary and conclusions

Copyright notices

References

8 Uncoordinated femtocell deployments

8.1 Introduction

8.2 Femtocell market

8.3 Femtocell deployment scenarios

8.4 The Small Cell Forum

8.5 Backhaul

8.6 Synchronization and localization

8.7 Interference mitigation in femtocell networks

8.7.1 Carrier allocation strategies

8.7.2 Power-based techniques

8.7.3 Antenna-based techniques

8.7.4 Load-balancing-based techniques

8.7.5 Frequency-based techniques

8.8 Summary

Copyright notices

References

9 Mobility and handover management

9.1 Introduction

9.2 Mobility management in RRC-connected state

9.2.1 Overview of the handover procedure in LTE systems

9.2.2 Handover failures and ping-pongs

9.2.3 Improved schemes for mobility management in RRC-connected state

9.3 Mobility management in RRC-idle state

9.3.1 Overview of cell selection/reselection procedure

9.3.2 Improved schemes for mobility management in RRC-idle state

9.4 Mobility management in heterogeneous cellular networks

9.4.1 Range expansion, almost blank subframes, and HO performance

9.4.2 HCN mobility performance with 3GPP Release-10 eICIC

9.4.3 Mobility-based intercell interference coordination for HCNs

9.5 Conclusion

Copyright notices

References

10 Cooperative relaying

10.1 Relay function

10.1.1 AF and DMF relay

10.1.2 Throughput comparison

10.1.3 Link adaptation of DMF relay

10.2 Relay architecture in LTE-Advanced

10.2.1 Interface and architecture

10.2.2 Protocol stack

10.3 Cooperative relaying

10.3.1 Introduction

10.3.2 Cooperative EF relay

10.3.3 Joint network-channel coding for user cooperation

10.4 Conclusion

Acknowledgment

Copyright notices

References

11 Network MIMO techniques

11.1 Introduction

11.2 General principles of network MIMO

11.2.1 Problems of single-cell processing

11.2.2 Advantages of multi-cell processing

11.2.3 Capacity results

11.2.4 Categories of network MIMO

11.3 Application scenarios of network MIMO in HCN

11.3.1 Backhaul limit in HCN

11.3.2 Clustering mechanism for HCNs

11.3.3 CSI sharing

11.4 Distributed downlink coordinated beamforming for macrocell network

11.4.1 System model and problem formulation

11.4.2 Distributed multi-cell beamforming based on interference leakage

11.4.3 Distributed multi-cell beamforming based on max--min SINR

11.4.4 Analysis of distributed implementation

11.4.5 Simulation results

11.5 Downlink coordinated beamforming applications in HCN

11.5.1 System model

11.5.2 Downlink multi-cell beamforming approaching Pareto optimality with max-min fairness

11.5.3 Performance analysis

11.5.4 Distributed implementation

11.5.5 Simulation results

11.6 The road ahead of network MIMO in HCN

11.7 Summary and conclusions

References

12 Network coding

12.1 Introduction

12.2 Coding opportunities in heterogenous cellular networks

12.2.1 An upper bound on coding gain without geometry consideration

12.2.2 An upper bound on coding gain with geometry consideration

12.2.3 Generalized butterfly network

12.2.4 Necessary condition for network coding gain

12.2.5 Supporting examples

12.3 Efficiency and reliability

12.3.1 Issues of naive interference cancellation

12.3.2 WNC-based partial interference cancellation strategy

12.3.3 Practical considerations

12.3.4 Diversity-multiplexing tradeoff analysis

12.4 Construction of distributed coding solutions

12.5 Summary and conclusion

References

13 Cognitive radio

13.1 Introduction

13.2 Cognitive radio techniques

13.2.1 Spectrum awareness

13.2.2 Spectrum selection

13.2.3 Spectrum sharing

13.2.4 Spectrum mobility

13.2.5 Summary of cognitive radio techniques and cross-layer design

13.3 Application scenarios for cognitive radio in heterogeneouscellular networks

13.3.1 Rural broadband

13.3.2 Dynamic backhaul

13.3.3 Cognitive ad hoc networks

13.3.4 Capacity extension in cellular networks

13.3.5 Direct UE-to-UE communication in cellular networks

13.3.6 Coordination and cognitive X2 links

13.3.7 Cognitive femtocells

13.4 Standardization activities: the future of cognitive radio systems

13.5 Summary and conclusions

References

14 Energy-efficient architectures and techniques

14.1 Introduction

14.2 Green cellular projects and metrics

14.2.1 Green cellular network projects

14.2.2 A taxonomy of green metrics

14.2.3 How green are cellular networks?

14.3 Fundamental tradeoffs: capacity, energy, and cost

14.3.1 Introduction

14.3.2 Fundamental energy saving limits

14.3.3 Maximum spectral and energy efficiency

14.3.4 Maximum cost efficiency

14.4 Green cellular network architectures

14.4.1 Homogeneous deployment

14.4.2 Heterogeneous deployment

14.5 Green cellular transmission techniques

14.5.1 MIMO techniques

14.5.2 Interference reduction

14.5.3 Scheduling

14.6 Integrated heterogeneous cellular networks

14.6.1 Flexible heterogeneous cellular networks

14.6.2 Self-organizing networks

14.7 Discussion

14.7.1 Standardization of green cellular networks

14.7.2 Pricing in green cellular networks

14.7.3 New energy and materials

14.8 Conclusion

Copyright notices

References

Index