Luận Văn Robust Cross-Layer Scheduling Design in Multi-user Multi-antenna Wireless Systems

Acknowledgments

I AM DEEPLY INDEBTED to my supervisor, Prof. Vincent K.N. Lau for having invariably
given me his patient guidance, stimulating encouragement, and deep insights into my research and
my life as well. His enthusiastic attitude and extremely high efficiency has not only had a great
impact on my Ph.D study, but has also given me great impetus that I would be able to cherish in
my entire life. The completion of this thesis would not have been possible without his continual
support.

I am sincerely grateful to the Graduate School of HKU for having provided the Postgraduate
Studentship during the whole Ph.D program. I would like to thank Dr. N. Wong, Prof. J. Wang,
Dr. W.H Lam, and Prof. Roger Cheng for their insightful guidance, suggestions, and kind help
during my study. I would also like to thank Prof. Ricky Kwok, Prof. K.L Ho, and Prof. Li chun
Wang for serving on my thesis examination committee.
I truly appreciate the friendship of my friends for having created a pleasant working environ-
ment and for their helpful discussions. Special thanks go to Mr. Tyrone Kwok, Mr. Gan Zheng,
Mr. Carson Hung, Mr. David Hui, Doctors-to-be- Xiaoshan Liu , Guanghua Yang and Shaodan
Ma, Dr. Zhifeng Diao, Dr. Xiaohui Lin, and Dr. Yiqing Zhou for their kind help and insightful
discussions. Many thanks go to other friends in the lab and research group.
Finally, I would like to express my sincerest gratitude to my parents and my wife Ying Zheng
for their deepest love and constant support.


Table of Contents

Declaration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
x
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii
Notation and used symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Evolution and Challenge of Wireless Technology
Literature Survey . . . . . . . . . . . . . . . . .
Motivation and Problem Statement . . . . . . .
Thesis Research and Contributions . . . . . . .
Wireless Fading Channel - Characterizations and Mitigation . . . . . . . . . .
2.1.1 Large-Scale Fading . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.2 Small-Scale Fading . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.3 Mitigation Methods . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cross-Layer Scheduling and Adaptive Design in Multi-user Wireless Network
2.2.1 Adaptive Design in Physical Layer . . . . . . . . . . . . . . . . . . .
2.2.2 MAC Layer Scheduling Model . . . . . . . . . . . . . . . . . . . . .
Linear Transmit-receive Processing in Multi-antenna Base Station . . . . . . .
2.3.1 Zero-forcing Processing . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.2 Transmit MMSE Processing . . . . . . . . . . . . . . . . . . . . . . .
Uplink Scheduling Design with Outdated CSI . . . . . . . . . . . . . . . . . . . . . 22
Cross-Layer Downlink Scheduling and Rate Quantization Design with Imperfect
CSIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multi-user SIMO System Model . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 Channel Model with Outdated CSIT . . . . . . . . . . . . . . . .
3.2.2 Multi-user Uplink Physical Layer Model . . . . . . . . . . . . . .
3.2.3 Packet Outage Model . . . . . . . . . . . . . . . . . . . . . . . .
Uplink Space Time Scheduling Design . . . . . . . . . . . . . . . . . . .
3.3.1 System Utility Function . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 Optimal Solution with Perfect CSI . . . . . . . . . . . . . . . . .
3.3.3 Heuristic Solution with Perfect CSI - Genetic Algorithm . . . . . .
Scheduling with Outdated CSI . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1 Performance Degradation of Ideal Schedulers Due to Outdated CSI
3.4.2 Proposed Scheme A - Rate Quantization . . . . . . . . . . . . . .
3.4.3 Proposed Scheme B - Rate Discounting . . . . . . . . . . . . . . .
Numerical Results and Discussions . . . . . . . . . . . . . . . . . . . . .
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multi-user MISO System Model . . . . . . . . . . . . . . . . . . .
4.2.1 Downlink Channel Model . . . . . . . . . . . . . . . . . .
4.2.2 Imperfect CSIT Model . . . . . . . . . . . . . . . . . . . .
4.2.3 Multi-user Downlink Physical Layer Model . . . . . . . .
Problem Formulation of Cross-Layer Scheduling . . . . . . . . . .
4.3.1 Instantaneous Channel Capacity and System Goodput . . .
4.3.2 Cross-Layer Design Optimization . . . . . . . . . . . . . .
Solutions of the Optimization Designs . . . . . . . . . . . . . . . .
4.4.1 Combined Scheduling and Rate Quantization Optimization
4.4.2 Optimal Inner Scheduling Based on Imperfect CSIT . . . .
4.4.3 Optimal Transmission Modes Design . . . . . . . . . . . .
4.4.4 Summary of the Scheduler Solution . . . . . . . . . . . . .
Numerical Results and Discussions . . . . . . . . . . . . . . . . .
4.5.1 Performance of Regular Scheduler with Imperfect CSIT . .
4.5.2 Performance of Proposed Scheduler with Imperfect CSIT .
Performance Analysis of Downlink Scheduling for Voice and Data Applications . . 65
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Cross-layer Downlink Scheduling with Heterogeneous Delay Constraints . . . . . . 84
System Model . . . . . . . . . . . . . . . . . . . . . .
5.2.1 Channel model . . . . . . . . . . . . . . . . . .
5.2.2 Multi-user Physical Layer Model . . . . . . . .
5.2.3 Source Model - Voice and Data . . . . . . . . .
Space Time Scheduling for Heterogeneous Users . . . .
5.3.1 Asymptotic Spatial Multiplexing Gain . . . . .
5.3.2 Scheduling Algorithm . . . . . . . . . . . . . .
Numerical Results and Discussions . . . . . . . . . . .
5.4.1 Delay Performance of VoIP users . . . . . . . .
5.4.2 Spatial Multiplexing Gains on System Capacity
5.4.3 Transient Performance . . . . . . . . . . . . . .
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Model . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.1 Multi-user Physical Layer Model . . . . . . . . . . . .
6.2.2 Source Model - Delay Sensitive and Delay Insensitive .
Formulation of the Cross-layer Design for Heterogeneous Users
Solution of the Cross-Layer Optimization Problem . . . . . . .
6.4.1 Convex Optimization on (p1 , , pK ) . . . . . . . . . . .
6.4.2 Combinatorial Search on Admissible Set . . . . . . . .
Numerical Results and Discussions . . . . . . . . . . . . . . .
6.5.1 Delay Performance of the Proposed Scheduler . . . . .
6.5.2 System Throughput Performance . . . . . . . . . . . .
6.5.3 Delay and Power Tradeoff . . . . . . . . . . . . . . . .
Conclusions and Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
7.1
7.2
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
List of References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105