Towards Efficient and Fair Radio Resource Allocation Schemes for Interference-Limited Celluar Networks

Abstract

The focus of this thesis is on studying the tradeoff between efficiency and fairness in interference-limited cellular networks. We start by characterizing the optimal tradeoff between efficiency and fairness in general resource allocation problems, including those encountered in cellular networks, where efficiency is measured by the sum-rate and fairness is measured by the Jain's fairness index. Among the commonly-used methods to approach these problems is the one based on the α-fair policy. Analyzing this policy, we show that it does not necessarily achieve the optimal Efficiency-Jain Tradeoff (EJT) except for the case of two users. When the number of users is greater than two, we prove that the gap between the efficiency achieved by the α-fair policy and that achieved by the optimal EJT policy for the same Jain's index can be unbounded. Finding the optimal EJT corresponds to solving potentially difficult non-convex optimization problems. To alleviate this difficulty, we derive sufficient conditions, which are shown to be sharp and naturally satisfied in various radio resource allocation problems. These conditions provide us with a means for identifying cases in which finding the optimal EJT can be reformulated as convex optimization problems. The new formulations are used to devise computationally-efficient resource schedulers that achieve the optimal EJT and surpass the baseline schedulers in terms of sum-rate efficiency, Jain's fairness index, median rate, and user satisfaction, without incurring additional complexity.Applying the proposed optimal EJT schedulers in interference-limited cellular iii First and foremost, I am grateful to Allah (God), the Gracious and the Merciful, for all that I am and all that I have. To my parents, Salem and Ferdous, I cannot thank you enough for the unconditional love and support since my first breath in this world. To my lovely wife, Areej, I must express my sincere appreciation for providing the best environment a husband can hope for to do this research, despite being an undergraduate student yourself with a very busy schedule. To my sisters and brothers, thanks for all your support during this research. To Dr. Mohammed Ali Al-Ghalayini and Mr. Mohammed Gayed, I would like to express my sincere gratitude for mentoring and guiding me throughout my undergraduate and graduate studies. I am very thankful for the encouragement, patient guidance, and the endless support I received from my supervisor Dr. Halim Yanıkömeroḡlu during my Master's and PhD studies. Most notably, I would like to thank him for his tremendous efforts to build and continuously expand such a dynamic and large research group with members from around the globe. Needless to say, the interaction with the members of the research group has significantly contributed to my knowledge and skills.