Development of a Modified Handover Decision Algorithm for Inter-Femtocell Handover in Long Term Evolution Network

Development of a Modified Handover Decision Algorithm for Inter-Femtocell Handover in Long Term Evolution Network.

ABSTRACT

The present-day cellular network faces an increasing problem of providing capacity and coverage for users. The Long Term Evolution (LTE) system provides a number of ways in mitigating these problems among one of which is the deployment of femtocell technology.

The femtocell is an example of a heterogeneous network that comprises different layers of different cell sizes ranging from microcell, picocell, and radio relay nodes.

The femtocell is the least in size of network densification and is deployed in indoor environments. Deployment of femtocells is not without its challenges, among which is frequent handover.

The problem of frequent handover arises from the nature of the femtocell owing to its unplanned deployment, small cell size, and access control techniques. The frequent handovers in femtocells reduce the user‟s call quality.

This research work addressed the frequent handover problem by considering the users’ motion as it changes, using the Link Expiration Time (LET) method and the inter-femtocell handover scheme of Rajabizadeh and Abouei in order to accommodate mobile users whose speeds are varying.

This scheme was designed to establish a communication link with the nearest femtocell when the user’s speed undergoes an abrupt change.

The developed handover scheme was implemented using a developed Graphical User Interface (GUI) in MATLAB and its performance was evaluated with the traditional handover scheme based on the number of handovers and the time interval between handovers as performance metrics.

It was observed from the results obtained that the developed handover scheme performed fewer handovers in comparison to the 3GPP handover scheme which was better by 24.17%.

TABLE OF CONTENT

CHAPTER ONE: INTRODUCTION
1.1Background 1
1.2 Motivation3
1.3 Statement of Research Problem3
1.4 Aim and Objectives4
1.5 Scope of Dissertation 4
1.6 Significance of Research 4
CHAPTER TWO: LITERATURE REVIEW
2.1 Introduction 5
2.2 Review of Fundamental Concepts 5
2.2.1 Long Term Evolution System Architecture5
2.2.2 Handover7
2.2.3 Femtocells17
2.2.4 Link Expiration Time Mobility Prediction 23
2.4 Review of Similar Works 24
CHAPTER THREE: RESEARCH METHODOLOGY
3.1 Introduction 32
3.2 Replication of Inter-Femtocell Handover33
3.2.1 Development of Femtocell Block33
3.2.2 Development of Macrocell-Femtocell Architecture34
3.2.3 Mobility Model35
3.2.4 Path Loss Model36
3.2.5 Received Signal Strength36
3.2.6 Candidate Cell List and Neighbour Femtocell List37
3.3 Development of modified inter-Femtocell Handover Scheme 39
3.4 The Graphical User Interface42
3.4.1 Simulation Parameters42
3.5 Simulation Setup and Assumptions44
3.6 Performance Evaluation 47
3.7Summary47
CHAPTER FOUR: RESULT AND DISCUSSION
4.1 Introduction48
4.2 Results 48
4.2.1 Number of Handovers48
4.2.2 Handover Count per Velocity49
4.2.3 Average Time between Handovers51
4.3 Summary of Results 53
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1 Conculsion54
5.2 Significant Contribution 54
5.3 Recommendations for Further Study55
REFERENCES 56

INTRODUCTION

1.1 Background

consumer demand for data and poor quality within buildings are two mobile network operators with.

In mobile communication, it is estimated that nearly two-thirds of the calls made and over 90% of data usage occurs indoors (Zhang & De la Roche, 2010) and according to a study carried out by Cisco, observed that the global mobile data traffic will increase nearly 11-fold between 2013 and 2018(Cisco, 2014).

This rapid increase in mobile data activity has led to the development of innovative new technologies and cellular topologies that can meet these demands(Andrews et al., 2012).

In order to achieve high data rate communications, the transmitter and receiver can be brought closer to each other to improve system capacity. An example of such an idea is femtocell technology(Chandrasekhar et al., 2008).

A femtocell, also known as a home base station or femtocell access point (FAP), is a short-range, low-cost, low-powered base station installed by a user for better indoor voice and data reception(Chandrasekhar et al., 2008).

REFERENCES

3GPP. (2009). Simulation Assumptions and Parameters for FDD HeNB RF Requirements. R4-092042 TSG RAN WG4 (Radio) Meeting 51, 1-8.
3GPP. (2012). 3rd Generation Partnership Project; Technical Specification Group Radio Access Network;Evolved Universal Terrestrial Radio Access (E-UTRA) Radio Resource Control (RRC); Protocol specification (Release 11) 3GPP TS 36.331 V11.0.0. TS 36.331, 215-230.
3GPP. (2013). 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 11) 3GPP TS 36.300 V11.4.0. 64-70.
A. Bhuvaneswari, & E. George Dharma Prakash Raj. (2011). Survey of Handoff Techniques. Journal of Global Research in Computer Science, 2(6), 140-144.
Ali-Yahiya, T. (2011). Understanding LTE and its Performance. New York: Springer Science & Business Media. 131-135