Final Draft thesis

Resource Allocation Techniques for
Non-Orthogonal Multiple Access
Systems
Haitham Al-Obiedollah
Doctor of Philosophy
University of York
Electronic Engineering
September 2019

To my family . . .

Acknowledgements
I would like to thank my supervisor, Dr. Kanapathippillai Cumanan, for his generous
support, guidance, and unbounded enthusiasm. It has been a privilege working under his
supervision. Thank you also to my co-supervisor, Prof. Alister G. Burr, for his kind support
and guidance. In fact, the accomplishment of this study would not have been feasible without
the kind support and cooperation of my supervisors. Many thanks also go to my research
collaborators: Dr. Jeyarajan Thiyagalingam, Prof. Zhiguo Ding and Prof. Octavia A. Dobre.
Their help, support, and contribution are much appreciated. I would like also to thank Dr.
Rami Al-Obiedollah, who has helped me very much in the very first few days of my arrival
to the United Kingdom and has been always there to support during my PhD journey. All
my thanks and love to my wife Lara, my son Moffaq, and my daughter Lana who brought
great deal of inspiration to my life, despite of the long distances that separated us during
this journey, they were always there for me to brighten my way and motivate me to work
harder. Furthermore, I would like to extend my heartfelt gratitude to my parents, my brothers,
and sisters for whom I am eternally grateful for their love and encouragement. Finally, I
would like to thank The Hashemite University for providing the funding which allowed me
to undertake this research.

Abstract
Non-orthogonal multiple access (NOMA) has been proposed as a viable multiple access (MA)
technique to meet the demanding requirements in fifth-Generation (5G) and beyond wireless
networks. Unlike conventional orthogonal multiple access (OMA) techniques, NOMA si-
multaneously sends signals to multiple users in the same resource block (RB) in time and
frequency domains using power-domain superposition coding (SC) at transmitter. Therefore,
NOMA has the potential capabilities to serve a large number of devices while significantly
improving spectrum efficiency (SE) compared to the conventional MA techniques, which
supports massive connectivity of Internet-of-Things (IoT) networks.
To introduce additional degrees of freedom, and hence facilitate implementing NOMA
in ultra-dense networks, NOMA has been integrated with different key technologies in-
cluding multiple antenna techniques and conventional OMA techniques. In particular, the
combination between multiple-input single-output (MISO) and NOMA, referred to as MISO-
NOMA, is firstly considered in this thesis. In which, different beamforming designs have
been proposed for MISO-NOMA system, including global energy efficiency maximization
(GEE-Max) design and EE fairness-based designs. In addition, different multi-performance
metrics have been also considered in the designs including GEE-SE design and fairness-sum
rate design. Due to non-convexity of the formulated optimization problems, different convex
relaxation and approximation techniques have been exploited throughout the thesis to ap-
proximate the original non-convex problems with convex problems. The performance of the
proposed designs has been evaluated through drawing comparisons with that of the existing
beamforming designs in the literature.
Secondly, the combination of NOMA with OMA scheme has been investigated, partic-
ularly, energy harvesting (EH) capabilities of time division multiple access (TDMA) and
NOMA system has been considered. In this hybrid TDMA-NOMA system, simultaneous
wireless information and power transfer (SWIPT) technique is integrated such that user has
the capability to harvest energy and decode information, simultaneously. Simulation results
show that EH capabilities of the TDMA-NOMA system outperform that of the conventional
TDMA system.

Table of Contents
List of Figures viii
List of Tables x
List of Notations xii
List of Acronyms xiii
1 Introduction 1
1.1 Overview................................... 1
1.2 Towards5GandBeyond ........................... 2
1.2.1 5GRequirements........................... 2
1.3 Towards Non-orthogonal Multiple Access . . . . . . . . . . . . . . . . . . 3
1.3.1 Conventional Multiple Access Techniques . . . . . . . . . . . . . . 3
1.3.2 Non-Orthogonal Multiple Access . . . . . . . . . . . . . . . . . . 5
1.4 ThesisOutline................................. 6
2 Fundamental Concepts and Literature Review of NOMA 10
2.1 NOMAFundamentals ............................ 10
2.1.1 Superposition Coding and Successive Interference Cancellation . . 11
2.1.2 A Simple SISO NOMA/OMA Scenario . . . . . . . . . . . . . . . 11
2.1.3 Advantages of NOMA . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2 NOMA with other Techniques . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.1 NOMA with Multiple-Antenna Techniques . . . . . . . . . . . . 15
2.2.2 NOMA with OMA Techniques . . . . . . . . . . . . . . . . . . . . 18
2.3 Energy-Efficient Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.1 Energy-Efficient-Resource Allocation Techniques . . . . . . . . . . 19
2.3.2 Simultaneous Wireless Power and Information Transfer . . . . . . 20
2.4 LiteratureReview............................... 20