GROUP SCHEDULING IN ADVANCED CELLULAR SYSTEMS USING DIRECTIONAL ANTENNAS A THESIS IN Electrical Engineering Presented to the Faculty of the University of Missouri—Kansas City in partial fulfillment of the requirements for the degree MASTER OF SCIENCE by Zhaoyang Qu B.E. Beijing Institute of Technology, Beijing, China, 2009 Kansas City, Missouri 2012 ©2012 ZHAOYANG QU ALL RIGHTS RESERVED GROUP SCHEDULING IN ADVANCED CELLULAR SYSTEMS USING DIRECTIONAL ANTENNAS Zhaoyang Qu, Candidate for the Master of Science Degree University of Missouri—Kansas City, 2012 ABSTRACT Long Term Evolution has been the most popular technique all around the world, and Multi-User Multiple Input Multiple Output is widely considered a key technology for system capacity improvement in modern wireless networks. At the same time how to improve throughput maximization and user’s fairness in the network is becoming an advanced issue. Beamforming technology and group scheduling have provided a new method to address this issue. This work provides the trade-off between efficiency and fairness using group scheduling, including the Maximum Carrier to Interference, Round Robin and Proportional Fairness scheduling schemes, under the consideration of the fairness of each group in the wireless networks. This is vitally important for increasing both the total and individual group’s throughput. Beamforming technology is used to increase the throughput at the direct angle area where the beam focuses. This is especially helpful for the mobile users iii at the edge of the network cell, who will usually have the worst channel conditions. Beamforming will increase the Signal-to-Noise Ratio by 5dB as designed. Also, the beam will switch its angle with some certain feedback algorithms, such as those based on the decreasing of the possible Signal-to-Noise Ratio compared with its previous time slot, the maximum and minimum difference of possible and location Signal-to-Noise Ratio, using the throughput measurement in the algorithms respectively. These schemes will boost the signal strength and also lead to increased total throughput, but at the same time they will face fairness requirements between the groups. From simulation result, it is shown that with every beamforming type, the throughput will have certain increases. While at the same time the fairness has been improved. Some new approaches have addressed the guarantee of the minimum throughput for every group. Moreover, with the adjustment of the key parameters our simulation is more close to the real wireless networks, which expresses a future view of the wireless networks. APPROVAL PAGE The faculty listed below, appointed by the Dean of the School of Computing and Engineering have examined a thesis titled “ Group Scheduling in Advanced Cellular Systems using Directional Antennas”, presented by Zhaoyang Qu, candidate for the master of Electrical Engineering degree, and certify that in their opinion it is worthy of acceptance. Supervisory Committee Cory Beard, Ph.D. Department of Computer Science and Electrical Engineering Ghulam Chaudhry, Ph.D. Department of Computer Science and Electrical Engineering Baek-Young Choi, Ph.D. Department of Computer Science and Electrical Engineering CONTENTS ABSTRACT ....................................................................................................................... iii ILLUSTRATIONS .......................................................................................................... viii TABLES .............................................................................................................................. xi Chapter 1.INTRODUCTION ............................................................................................................ 1 1.1 Project Overview............................................................................................................ 3 1.2 Aim of the Project .......................................................................................................... 3 1.3 Issues in the Proposal ..................................................................................................... 5 1.4 Solutions ......................................................................................................................... 6 1.5 Conclusion ..................................................................................................................... 9 2. BACKGROUND DETAILS .......................................................................................... 10 2.1 Long Term Evolution (LTE) ........................................................................................ 10 2.2 Multiple-User Multiple-Input Multiple-Output (MU-MIMO) .................................... 11 2.3 Beamforming ............................................................................................................... 13 2.4 Fading ........................................................................................................................... 16 2.5 Group Scheduling ........................................................................................................ 18 2.5.1 Maximum Carrier to Interference (Max C/I) ..................................................... 20 2.5.2 Round Robin (RR) ............................................................................................. 21 2.5.3 Proportional Fairness (PF) ................................................................................. 21 vi 2.6 Related Work ............................................................................................................... 23 3.SIMULATION DESIGN ................................................................................................ 26 3.1 Introduction to MATLAB ............................................................................................ 26 3.2 Brief Introduction to MATLAB Simulation Code ...................................................... 26 3.3 Explanation of Key Blocks of MATLAB Code for this Project.................................. 28 3.4 Programming Diagnosis ............................................................................................... 36 4.SIMULATION RESULTS AND ANALYSIS ............................................................... 47 4.1 Simulation Result and Analysis ................................................................................... 47 4.1.1 Comparison of the different beamforming types ............................................... 47 4.1.2 Guarantee the Minimum Throughput of the Beamforming Types 4 and 6 ....... 53 4.1.3 Furthure improvement of beamforming type 6 .................................................. 58 4.2 Simulation Parameters ................................................................................................. 62 4.2.1 Transmission Block ............................................................................................ 62 4.2.2 Directional Gain ................................................................................................. 63 4.2.3 Total Number of Users ....................................................................................... 64 4.3 Conclusion ................................................................................................................... 66 5.CONCLUSION AND FUTURE SCOPE ....................................................................... 67 REFERENCE LIST ........................................................................................................... 69 VITA .................................................................................................................................. 72 vii ILLUSTRATIONS Figure Page 1. Plot of the overview of the wireless system scenario………………………………7 2. Code for the Okumura-Hata model…. ………………………………………….28 3. Code for dividing by angle……………………………………... ………...…..….29 4. Code of sorting distances and angles…… ……..…………….…………..……..29 5. Distance and angle map with random values……. …….……..……………........30 6. Code of matching SNR to throughput………… ……...……..……….….……....31 7. Step charts of SNR classes and throughput ……………………………………….32 8. Code of creating actual SNR, location SNR, and difference between these two SNRs……. ……...…………………………………………………………….32 9. The calculation details of beamforming type 1 …………………………………35 10. Code of scheduling types………………………………… ……………..….......36 11. Simulation result of beamforming type 5 and scheduling type 1.... ……….........38 12. Simulation result of beamforming type 5 and scheduling type 2 ……………….39 13. Simulation result of beamforming type 5 and scheduling type 3… ………….…40 14. Plot of time slots allocated to each user……………………………… ………….41 15. Plot of throughput allocated to each user……………………..…… ………….....41 16. Plot of total throughput distribution with three scheduling types ……………….44 17. Distance and angle map with testing values……………………….… …….….....45 viii 18. Plot of total throughput for each beamforming type…………………… ..….........48 19. Plot of fairness based on time slots between groups for the beamforming type 0, 1, 2 and 3 …………………………………………………………………..51 20. Plot of fairness based on time slots between groups for the beamforming type 0, 4, 5 and 6……………………………………………………………...……51 21. Plot of fairness based on throughput between groups for the beamforming type 0, 1, 2 and 3 …………………………………………………………………..52 22. Plot of fairness based on throughput between groups for the beamforming type 0, 4, 5 and 6 …………………………………………………………………..52 23. Plot of system throughput