Mobile Small cells in

Cellular Heterogeneous Networks

by

Mahmoud H. Qutqut

A thesis submitted to the

Graduate Program in the School of Computing

in conformity with the requirements for

the degree of Doctor of Philosophy

Queens University

Kingston, Ontario, Canada

September 2014

Copyright c Mahmoud H. Qutqut, 2014

Dedication

Dedicated to my beloved parents, Hussam and Yussra, my lovely wife, Samar, my

sweetheart daughter, Liya, and my loving siblings-Mohammad, Mohannad, Morad,

Moayad, and Manar.

i

Abstract

The unprecedented soaring demand for capacity and coverage on cellular networks is

challenging and straining operators. The current improvements in cellular standards

are significantly behind the exponential growth in requirements. Cellular operators

are currently shifting towards Heterogeneous Networks (HetNets) as the most promis-

ing solution to meet user demands; by using a mix of Macro Base Stations (MBSs)

and Small Base Stations (SBSs).

Recently, several cellular operators have started outdoor deployments of small

cells to enhance service in high-dense areas (e.g., downtown areas). In this the-

sis we assess and propose HetNet solutions that capitalize on SBS deployments to

boost capacity and coverage under varying scenarios. Initially we investigate the core

challenge of SBS placement in high-demand outdoor zones. We propose dynamic

placement strategies (DPS) for SBSs, and present two models that optimize place-

ment while minimizing service delivery cost when feasibility is the core challenge, and

minimizing macrocells utilization as their deployment, compared to small cells, pose

a constant challenges. Both problems are formulated as Mixed Integer Linear Pro-

grams (MILPs). These solutions are contrasted to two greedy schemes which we have

presented and evaluated over extensive simulations. Our simulation results demon-

strate that our proposed DPS achieve significant reductions of service delivery cost

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and MBSs utilization.

Realizing that a significant amount of cellular demand is generated on the go and

suffers deteriorating quality, recent research efforts proposed deploying SBSs onboard

public transit vehicles to enhance cellular coverage. We investigate the potential

performance gains of using mobile SBSs (mobSBSs). We assess and quantify the

impact of utilizing mobSBSs which are deployed in vehicles to aggregate traffic and

backhaul it to MBS. In our evaluation we study two important indicators to as-

sess the Quality of Service (QoS) received by mobile users, and the ensuing network

performance. Namely, we investigate Pairwise Error Probability (PEP) and Outage

Probability (OP) for mobile users.

Finally, we propose a novel mobile data offloading framework which capitalizes

on mobile small cells and urban Wireless Fidelity (WiFi) zones to alleviate the data

traffic load generated onboard on MBSs. We incorporate dedicated and adaptive

offloading mechanisms that take into account mobile user service profiles (history)

and WiFi coverage maps to improve the efficiency of the offloading framework. We

conduct extensive simulation experiments to evaluate the performance of the mobile

offloading framework and contrast results to a benchmark.

iii

Co-Authorship

Book Chapter

1. M. Qutqut and H. S. Hassanein, Mobility Management in Femtocell Networks,

in Future Wireless Networks: Architecture, Protocols and Services, edited by

N. Beaulieu, E. Biglieri and M. Guizani, CRC Press, 2015.

Journal Articles

1. M. Qutqut, H. Abou-zeid and H. S. Hassanein, Dynamic Small Cell Placement

Strategies for LTE Heterogeneous Network, (in preparation).

2. M. Qutqut, M. Feteiha and H. S. Hassanein, Analyzing the performance gain

of using Mobile Small cells, Submitted to IET Journal, Aug 2014.

Conference Papers

1. M. Qutqut, M. Feteiha and H. S. Hassanein, Outage Probability Analysis of

Mobile Small cells over LTE-A Networks, Proc. International Wireless Com-

munications and Mobile Computing Conference (IWCMC), Aug. 2014.

2. M. Qutqut, H. Abou-zeid, H. S. Hassanein, A. Rashwan and F. Al-Turjman,

Dynamic Small Cell Placement Strategies for LTE Heterogeneous Network,

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Proc. IEEE Symposium on Computers and Communications (ISCC), June

2014.

3. M. Feteiha, M. Qutqut and H. S. Hassanein, Pairwise Error Probability Eval-

uation of Cooperative Mobile Femtocells, Proc. IEEE Global Communications

(GLOBECOM), Dec. 2013, pp. 4588-4593.

4. M. Qutqut, F. Al-Turjman and H. S. Hassanein, HOF: A History-based Of-

floading Framework for LTE Networks Using Mobile Small Cells and Wi-Fi,

Proc. IEEE Local Computer Networks (LCN) workshops, Oct. 2013, pp. 77-83.

5. M. Qutqut, F. Al-Turjman and H. S. Hassanein,MFW: Mobile Femtocells uti-

lizing WiFi, Pros. IEEE International Conference on Communications (ICC),

June 2013, pp. 5020-5024.

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Acknowledgments

First and foremost, I am thankful to God, Almighty, for his guidance, blessing and

mercy throughout the work of my PhD journey and all that I have endured.

My deep and sincere thanks go to my advisor, Dr. Hossam Hassanein. I am

indebted to him forever for his guidance, patience, encouragement, and strong support

during my PhD program. He was not only my advisor, but he was a friend and an

older brother for all of us, especially during the tough times when I was frustrated

and couldnt see the tunnel up ahead. I will never, ever forget him, his actions, and

what he did for me throughout this process. I learned from my advisor that education

is not just academic, but that education is also about learning about life.

I am lucky to have worked and collaborated with Drs. Fadi Alturjman, Moham-

mad Feteiha and Hatem Abou-zeid. I have learned much from each one of them, and

I extend and express my gratitude for everything. Many individuals have assisted me

throughout my PhD journey; I am grateful to all of them.

I would like to thank the members of my supervisory and examination committees

for their valuable feedback and recommendations to enhance the thesis. I would also

like to express my deepest thanks to my friends Drs. Abdallah Almaaitah and Sharief

Oteafy for their support during the writing of my thesis and for helping me with the

revisions and the editing.

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From the bottom of my heart, I would like to sincerely thank my beloved parents.

I have no words to thank you for everything you have done over the years. You have

stood by me through every single thing in my life and I will never be able to pay you

back for all that you have sacrificed. I am proud to be your son and I will always love

you.

To my lovely wife, Samar: you have been a source of motivation and strength

during moments of despair and discouragement. I am eternally grateful for your love,

endless support and inspiration. I am so very blessed to have you and our daughter

in my life. I am sorry for the tough times, but you are my anchor who kept me going.

I am grateful to my siblings for their love, support, and believing in me. You have

always given me the strength I have needed, and you are the rock on which I stand.

I would like to thank all my cousins throughout the world.

Thank you to all my friends and colleagues in the Telecommunications Research

Lab and in the School of Computing at Queens University for their support and

friendship, namely Abdulmonem, Abdulrahman, Bader, Khaled Hayajneh, Khalid

Elgazzar, Loay, Lobna, Mohannad, Ouda, Sherin, Walid, and Yaser. I would like

to extend a thank you to the lab coordinator Basia Palme and school of computing

staffs, Debby Robertson and Richard Linley.

I thank all my friends here in Canada, back home in Jordan, and all over the world,

without whom none of my success would be possible. Special thanks to Queens Uni-

versity, and Applied Science University in Amman, Jordan for their financial support.

Mahmoud H. Qutqut

Kingston, Ontario

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Statement of Originality

I hereby certify that, to the best of my knowledge, all of the work presented within this

thesis is the original work of the author. Any published (or unpublished) ideas from

the work of others are fully acknowledged in accordance with the standard referencing

practices.

Mahmoud Qutqut

September 2014

viii

List of Acronyms

3G 3rd Generation

3GPP 3rd Generation Partnership Project

4G 4th Generation

AP Access Point

AWGN Additive White Gaussian Noise

BEM Basis Expansion Model

BS Base Station

CDF Cumulative Distribution Function

CN Core Network

CRC Cyclic Redundancy Check

DF Decode and Forward

DFT Discrete Fourier Transform

DL Downlink

eNB evolved Node B

HetNet Heterogeneous Network

LOS Line of Sight

LTE Long Term Evolution

LTE-A Long Term Evolution-Advanced

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M-QAM Multi-level Quadrature Amplitude Modulation

MBS Macro Base Station

Mbps Megabit per second

MILP Mixed Integer Linear Program

ML Maximum Likelihood

mobSBS Mobile Small Base Station

NGMN Next Generation Mobile Networks

NLOS None Line of Sight

OFDM Orthogonal Frequency Division Multiplexing

OP Outag