ABSTRACT
The major problems of most wireless technologies such as EDGE, HSPA, WiMax, HSPA+, WiFi G, WiFi and LTE are the imbalance of radio resources allocation as well as unfairness and difficulty to achieve unity index. These result in overstressing the networks while leaving some idle. This imbalance of resources amongst the networks brings about poor quality of service. Most researchers including Donoso et al (2014) tried to resolve the problem using different techniques such as the Round Robin Algorithm (RRA), the Least Connected Algorithm (LCA) and the Min- Max strategy. In an effort to resolve the same problems in heterogeneous wireless networks, the combination of Monte Carlo scheduling algorithm and Load leveling algorithm were used in this research as a developed algorithm for this purpose. The results obtained in this research were then compared with those from Donoso et al (2014). The improvement made by this developed 2- step algorithm of Monte Carlo and Load leveling algorithm achieved global fairness of 2.72% better than Donoso et al (2014), it also showed a strong and steady convergence towards unity which is the desired optimal index in fairness. The significance of the achieved result translates to better resource utilization among the wireless access technologies.
TABLE OF CONTENTS
TITLE PAGE………………………………………………………………………………i
DECLARATION …………………………………………………………………………………………………… ii
CERTIFICATION ………………………………………………………………………………………………… iii
DEDICATION ……………………………………………………………………………………………………… iv
ACKNOWLEDGEMENT ………………………………………………………………………………………. v
ABSTRACT …………………………………………………………………………………………………………. vii
TABLE OF CONTENTS …………………………………………………………………………………….. viii
LIST OF FIGURES ……………………………………………………………………………………………….. x
LIST OF TABLES ………………………………………………………………………………………………… xi
LIST OF ABBREVIATIONS ………………………………………………………………………………… xi
CHAPTER ONE: INTRODUCTION
1.1 BACKGROUND OF STUDY ………………………………………………………………………………. 1
1.2 STATEMENT OF RESEARCH PROBLEM ………………………………………………………… 2
1.3 SIGNIFICANCE OF THE RESEARCH ………………………………………………………………. 2
1.4 AIM AND OBJECTIVES…………………………………………………………………………………….. 3
1.5 SCOPE OF REEARCH ……………………………………………………………………………………….. 3
CHAPTER TWO: LITERATURE REVIEW
2.1 INTRODUCTION …………………………………………………………………………………………………….. 4
2.2 REVIEW OF FUNDAMENTAL CONCEPTS …………………………………………………………… 4
2.2.1 Heterogeneous Wireless Technologies ……………………………………………………………………. 4
2.2.2 Interworking of Heterogeneous Wireless Technologies ……………………………………………12
2.2.3 Load Balancing …………………………………………………………………………………………………..13
2.2.4 Fairness Index …………………………………………………………………………………………………….18
2.3 REVIEW OF SIMILAR WORKS ……………………………………………………………………………. 18
CHAPTER THREE: METHODOLOGY
3.1 INTRODUCTION ……………………………………………………………………………………………… 24
3.2 METHODOLOGY …………………………………………………………………………………………….. 24
3.3 SYTEM MODEL ………………………………………………………………………………………………. 25
3.3.1 Network Model …………………………………………………………………………………………………..25
3.3.2 The Received Signal Strength Indicator (Rssi) ………………………………………………………..26
3.3.3 Jain’s Fairness Index ……………………………………………………………………………………………27
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3.4 ROUND ROBIN, LEAST CONNECTED AND THE DEVELOPED ALGORITHMS ……… 28
3.4.1 The Round Robin Algorithm ………………………………………………………………………….28
3.4.2 The Least Connected Algorithm (LCA) ……………………………………………………………29
3.4.3 The Developed Algorithm ………………………………………………………………………………30
3.5 SIMULATION SETUP AND ASSUMPTIONS …………………………………………………… 34
CHAPTER FOUR: RESULTS AND DISSCUSSION
4.1 INTRODUCTION …………………………………………………………………………………………………… 37
4.1.1 Distribution of mobiles among the wireless technologies………………………………………….37
4.1.2 The Relative Error of RRA, LCA Donoso et al and The Developed Algorithm …………..42
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1 INTRODUCTION …………………………………………………………………………………………………… 46
5.2 CONCLUSION ……………………………………………………………………………………………………….. 46
5.3 SIGNIFICANT CONTRIBUTIONS ………………………………………………………………………… 47
5.4 LIMITATIONS AND FUTURE WORK ………………………………………………………………….. 47
REFERENCES …………………………………………………………………………………………………….. 48
Appendix A ………………………………………………………………………………………………….. 50
Appendix B ………………………………………………………………………………………………….. 52
Appendix C ………………………………………………………………………………………………….. 53
Appendix D ………………………………………………………………………………………………….. 55
Appendix E ………………………………………………………………………………………………….. 56
Appendix F ………………………………………………………………………………………………….. 57
Appendix G ………………………………………………………………………………………………….. 59
Appendix H ………………………………………………………………………………………………….. 60
Appendix I …………………………………………………………………………………………………… 61
Appendix J …………………………………………………………………………………………………… 63
Appendix K ………………………………………………………………………………………………….. 64
Appendix L …………………………………………………………………………………………………. 65
Appendix M …………………………………………………………………………………………………. 66
Appendix N ………………………………………………………………………………………………….. 67
Appendix O ………………………………………………………………………………………………….. 70
Appendix P ………………………………………………………………………………………………….. 72
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LIST OF FIGURES
Figure 2.1: Classification of Wireless Technologies …………………………………………………….. 5
Figure 2.2: GSM/EDGE Architecture (Hakanet al, 2006) ……………………………………………… 6
Figure 2.3: UMTS Network Architecture (Ali, 2012) …………………………………………………… 7
Figure 2.4: WiMAX Network Architecture (Ali, 2014) ………………………………………………… 8
Figure 2.5: Basic WLAN Architecture (Ali, 2012) ………………………………………………………. 9
Figure 2.6: HSPA+ Architecture(TEC,2014) …………………………………………………………….. 10
Figure 2.7: WLAN Basic Architecture (Singh et al, 2014) ………………………………………….. 11
Figure 2.8: Flat Architecture for the LTE (Ericsson, 2007) …………………………………………. 12
Figure 2.9 : Heterogeneous Wireless Technologies Coverage Areas Coexisting ……………. 13
Figure 2.10: flow chart for round robin scheduling process …………………………………………. 15
Figure 3.1: Flowchart of Randomized (Monte Carlo based) Algorithm ………………………… 31
Figure 3.2: Flowchart for the Load Levelling Algorithm …………………………………………….. 33
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF STUDY
The concept of wireless access networks emerged in the late 1980s as a byproduct of cellular wireless technology. As the demand for cellular service exploded worldwide, the cost of wireless network components decreased, while the cost for deploying and maintaining the conventional copper-based subscriber network increased (Gi & Choi, 2008).
The subscriber network, though it appears to be a small part of the overall telecommunications network, in reality occupies a considerably large portion of the overall network expenses, most of which is spent for deployment, operation, and maintenance of the subscriber lines. For this reason, the wireless subscriber network was first deployed in rural areas in the beginning where the initial cost is comparatively low. Later, it has become an effective alternative to the copper-based subscriber network in urban areas. It is very recent that the concept of mobile wireless access network was introduced (Gi & Choi, 2008)
In the past decade, there has been a remarkable growth in the use of wireless and mobile communications while on one hand the number of users accessing such services has increased, the amount of data traffic and types of applications have also increased. Though mobile networks were predominantly for voice communications in the past, the advent of 3G technology has seen a rise in the use of data services also. Hence, these wireless and mobile networks are now used for different types of voice and data communications. The users of these networks expect good service anytime and at anyplace. To cater for this ever increasing demand for data services has led to the development of various radio access technologies like 3G, 4G and IEEE 802.16 WiMAX that support high data rates and long communication ranges(Ali, 2012).
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Following the trend of increased mobile usage and high data demand, a global rollout of one new single radio access technology is not to be foreseen because of various needs in different parts of the world due to an unaligned distribution of radio spectrum, and network operators protecting their old investments. There will rather be a variety of existing and new wireless access technologies cooperating in delivering services to the users. This development is leading us into the field of heterogeneous wireless technologies where multiple radio access technologies (UMTS, WLAN, WiMAX, LTE, and coming radio access technologies) are simultaneously used (Andersson, 2010).
1.2 STATEMENT OF RESEARCH PROBLEM
When wireless access networks co-exist to provide services for a number of mobiles, the heterogeneity creates serious issues from how mobiles are seamlessly handed over across the access technologies to how fairly the limited radio resource is utilized. This research considers load balancing in terms of the radio resource and in the end, measures the degree of fairness of the balancing across the heterogeneous wireless technologies.
1.3 SIGNIFICANCE OF THE RESEARCH
Dealing with unequal load distribution of traffic load over different wireless technologies coexisting in the same location and in such a way that there is an even and load sensitive distribution across the networks is a serious concern for researchers in the field of Hetrogeneous Wireless technologies (HetNets) (Mengistie& Ronoh, 2012)
The aim of load balancing is to try to improve the performance of a distributed system, mainly in terms of resource availability or response time by distributing workload amongst a set of cooperating networks (Magade& Patankar, 2014)
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Balancing the limited radio resource will avoid over stretching access technologies and in turn reduces call drop rates and frequent handovers which all culminate to bad QoS.
1.4 AIM AND OBJECTIVES
The aim of the work is to develop an efficient decision-making algorithm to perform fair load balancing of radio resource among heterogeneous wireless technologies through the following objectives:
I. To adopt a heterogeneous wireless network model of seven different co-existing seven wireless technologies; EDGE, HSPA, WiMax, HSPA+, WiFi G, WiFi and LTE from the work of Donoso et al (2014)
II. To develop a two-step load balancing scheme comprising Randomized algorithm(RA) which is Monte Carlo based and Load leveling algorithm (LLA)
III. To validate the performance of the developed load balancing scheme against Min-Max strategy as presented in Donoso et al’s work in terms of fairness index.
1.5 SCOPE OF REEARCH
The research was undertaken in the field of Heterogeneous wireless networks comprising seven wireless access technologies; EDGE, HSPA, WiMax, HSPA+, WiFi G, WiFi and LTE. The sample considered was a thousand mobiles trying to access these technologies for either of three services; voice, data and video.
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