Comparative Analysis of Distributed Power Control Algorithms in Cellular Network

ABSTRACT

Wireless Communication is one of the most active areas of technological development of our time. It covers a very wide array of applications that lead to an ever growing demand on the limited radio resources. Consequently, the need for efficient management of the limited radio resources has become imperatively a global issue. The complexity of the cellular system and the propagation channel resulted in the interference issues that degrade the system performance. Transmit power otherwise known as Power Control is an efficient radio resource management technique that mitigates both adjacent and co-channel interference under fading condition. It also suppresses the Near – Far problems, enhances the battery life and the system capacity. In the light of this, different power control algorithms have been proposed by different authors but the choice of an appropriate power control algorithm is of great importance, as it should aim at improving the quality of service (QoS) to all the users and increasing the efficiency of the system. In this work, therefore, comparative analyses have been carried out on three popular distributed power control algorithms using performance metrics such as speed of convergence and total power consumption of the network. However, results have shown that Fully Distributed Power Control Algorithm (FDPCA) has a better efficiency in handling transmit power of the system more than New Distributed Power Control Algorithm (NDPCA) and Improved Distributed Power Control Algorithm (IDPCA) algorithms by 0.44% and 0.01% respectively, while IDPCA is more efficient in conserving power on the network than FDPCA and NDPCA by 0.04% and 2.38% respectively. Furthermore, analysis of variance (ANOVA) test carried out on the simulated data using means and standard deviation at 95% confidence level showed that the degree of variance of the algorithms is negligible.

TABLE OF CONTENT

TITLE PAGE- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - i

APPROVAL PAGE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --ii

CERTIFICATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - iii

DECLARATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - iv

DEDICATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - v

ACKNOWLEDGEMENT - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -vi

ABSTRACT - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - vii

LIST OF ACRONYMS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - viii

TABLE OF CONTENT - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -xii

LIST OF FIGURE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -xv

LIST OF TABLE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Xvii

CHAPTER ONE: INTRODUCTION

1.1 Background of Study - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1

1.2 Aims and objectives - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4

1.3 Problem Statement - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4

1.4 Scope of the Work - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - 5

1.5 Methodology - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -5

1.6 Thesis Structure - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -5

CHAPTER TWO: LITERATURE REVIEW

2.1 Overview of Cellular Systems - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7

2.2 UMTS services - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -- - - - - - - - 10

2.2.1 UMTS network servicesand QS classes - - - - - - - - - - - - - - - - - - - - - - - - -11

2.2.2 Universal Mobile Telecommunication Systems (UMTS) Architecture - - - - - -11

2.2.3 UMTS Physical Architecture - - - - - - - - - --- - - - - - - - - - - - - - - - - - - -12

2.3 Core Network - - - - - -- - - - - -- - - - - - -- - - - -- - - - - -- - - - - -- - - - - - - - - - ---13

2.3.1Mobile Switching Centre - - - - - -- - - - - -- - - - - -- - - - - -- - - - - -- - - - - - - -14

2.3.2 Visitor Location Register - - - - - - - - - - - -- - - - - -- - - - - -- - - - - -- - - - - - - 15

2.3.3 Home Location Register - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -16

2.3.4 Authentication Centre - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -17

2.3.5 Serving GPRS Support Node - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -17

2.3.6 Gateway GPRS Support Node- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17

2.4 UMTS Terrestrial Radio Access Network- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18

2.4.1 Node B (Base Station)- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - -19

2.4.2 Radio Network Controller (RNC)- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - -19

2.4.3 User Equipment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 20

2.4.4 UMTS Interface- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - 21

2.5 UMTS Protocol - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22

2.5.1 The Radio Interface Protocol Reference Model- - - - - - - - - - - - - - - - - - - - - - -22

2.5.2 (UTRAN) Protocol Reference Model- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - 24

2.5.3 Uu Interface Protocol- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - --25

2.6 Radio or Wireless Channel- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - - 27

2.6.1 Channel Organisation in WCDMA- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -28

2.6.2 Physical Channel - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28

2.6.3 Transport Channels- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - - - - - -29

2.6.3.1 Dedicated Transport Channel- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -29

2.6.3.2 Commons Transport Channels- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - 30

2.6.4 Logical Channels - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 32

2.7 Characteristic of Wireless Channels- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - -33

2.8 Functions of Radio Resource Management- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - -35

2.9 Importance of Power Control in UMTS - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - 37

2.10 Power Control Mechanism- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39

2.10.1 Open-Loop Power Control (OLPC)- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - 39

2.10.2 Closed-Loop Power Control (CLPC) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 40

2.11 Further Classifications of Power Control Algorithms - - - - - - - - - - - - - - - - - - - - - - -42

2.11.1 Centralized Power Control - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 42

2.11.2 Distributed power control- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - 43

2.12 Power Control Algorithms- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - 43

2.12.1 Uplink Power Control- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43

2.12.2 Downlink Power Control- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - 44

2.13 A Closed Loop Power Control Model for FDD-CDMA System- - - - - - - - - - - - - - - 45

2.14 Related Works on Power Control Algorithms- - - - - - - - - - - - - - - - -- - - - - - - - - - - 46

CHAPTER THREE: RESEARCH METHODOLOGY

3.1 Model Design - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - 49

3.1.1 Physical Model- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49

3.1.2 System Model- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - - - - - - 50

3.1.3 Modeling of the Channel - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - 51

3.1.4 Propagation and path loss model- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - 52

3.2 Flow chart of operation - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - 54

3.3 Three distributed power control algorithm chosen - - - - - - - - - - - - - - - - -- - - - - - - - - 55

3.3.1 First algorithm: Fully Distributed Power Control Algorithm- - - - - - - - - - - - - - - - - 55

3.3.2 Second algorithm:New Distributed Power Control Algorithm- - - - - - - - - - - - - - - - 58

3.3.3 Third algorithm: An Improved Distributed Power Control Algorithm- - - - - - - - - - - 60

CHAPTER FOUR: SIMULATION RESULTS ANALYSIS

4.1 Result and Analysis- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - -- - - - - - - - - - - - -62

4.2 Comparison of the three algorithms- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - 72

4.2.1 Speed of convergence - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - 72

4.2.2 Total Power Consumption on the Network- - - - - - - - - - - - - - - - -- - - - - - 73

4.3 Computation of the statistical analysis of the result in percentage- - - - - - - - - - - - - - - 75

4.4Analysis of Variance (ANOVA) table and its descriptive statistics- - - - - - - - - - - - - - 76

4.5Conclusion- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -78

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -80

5.2 Recommendation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 81

5.3 Contribution to Knowledge- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -81

REFERENCE- - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - -82