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 Queen's 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 ii 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", iv 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. v 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 couldn't 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 Alma'aitah and Sharief Oteafy for their support during the writing of my thesis and for helping me with the revisions and the editing. vi 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 Queen's 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 Queen's Uni- versity, and Applied Science University in Amman, Jordan for their financial support. Mahmoud H. Qutqut Kingston, Ontario vii 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 ix 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 Outage Probability PDF Probability Distribution Function PL Path Loss PEP Pairwise Error Probability QoS Quality of Service QPSK Quadrature Phase-Shift Keying RAN Radio Access Network RSCP Received Signal Code Power RSS Received Signal Strength SBS Small Base Station SINR Signal to Interference Plus Noise Ratio SNR Signal to Noise Ratio UL Uplink WiFi Wireless Fidelity UE User Equipment x List of Symbols Symbol Description i Candidate site index j eNB index Z Set of candidate sites A Set of eNBs in the network N Total number of SBSs that can be deployed xi The fraction of BS air-time allocated to candidate site i si Indicator variable representing SBS installation at candidate site i Di Demand