Non Orthogonal Multiple Access In Cooperative Relay Networks Based On Statistical Channel State Information

Non-orthogonal multiple access (NOMA) has been considered as an essential enabling technology for fifth generation (5G) and beyond 5G (B5G) cellular networks to meet the increasing demands on low latency, high reliability, massive connectivity, improved fairness, and high throughput. Cooperative relay networks, on the other hand, have been shown to significantly improve the throughput, coverage, and achievable rates of wireless networks, in which, the relay nodes assist the communication between the source node and the destination node when the direct channel is poor. There has been extensive research on the subject of NOMA and cooperative relay networks. However, most of the existing research relies on two main assumptions: flat fading channels and perfect channel state information (CSI) at the transmitting nodes. Instead of those idealistic assumptions, we study NOMA in cooperative relay networks under practical assumptions: frequency selective multipath fading channels and statistical CSI at the transmitting nodes. This dissertation begins with an overview of the basic concept of NOMA. Then, it focuses on downlink NOMA transmissions in a cooperative relay network. Specifically, a base station communicates with two paired mobile users simultaneously via superposition coded orthogonal frequency division multiplexing (OFDM) transmissions with the help of a half-duplex relay under either the decode-and-forward (DF) or amplify-and-forward (AF) scheme, where the power splitting between two mobile users depends on the statistical CSI. We derive the ergodic rates under Rayleigh fading channels and present an ad-hoc approach to determine the power splitting parameters when the target data rates are given. After that, this dissertation presents uplink NOMA transmissions in a cooperative relay network. Specifically, two users, a near user and a far user, communicate with a base station at the same time with existence of a half-duplex relay employing the DF scheme to assist the far user. At the transmitting nodes, the power allocation factors are decided based on the statistical CSI while, at the receiving nodes, the effect of imperfect successive interference cancellation (SIC) implementation is taken into account. Under Rayleigh fading channels, we derive the exact ergodic rate for the near user and the upper bound of the ergodic rate for the far user, then present an ad-hoc approach to determine the power allocation factors when the target data rates are given, and we study the outage probability of the two users at the base station. The last part of this dissertation extends the study into an energy harvesting cooperative wireless sensor network. We consider a two-hop network consisting of a source, two parallel half-duplex relay nodes, and two destinations. While the destinations have adequate power supply, the source and relay nodes rely on harvested energy for data transmission. Different from all existing works, the two relay nodes can also transfer their harvested energy to each other via energy conferencing channels. For such a system, an optimization problem is formulated with the objective of maximizing the total data rate and conserving the source and relay transmission energy.

With the growth of multimedia services, it is essential to find new transmission schemes to support higher data rates in wireless networks. In this thesis, we study networks in which the Channel State Information (CSI) is only available at the destination. We focus on the analysis of three different network setups. For each case, we propose a transmission scheme which maximizes the average performance of the network. The first scenario, which is studied in Chapter 2, is a multi-hop network in which the channel gain of each hop changes quasi-statically from one transmission block to the other. Our main motivation to study this network is the recent advances in deployment of relay nodes in wireless networks (e.g., LTE-A and IEEE 802.16j). In this setup, we assume that all nodes are equipped with a single antenna and the relay nodes are not capable of data buffering over multiple transmission blocks. The proposed transmission scheme is based on infinite-layer coding at all nodes (the source and all relays) in conjunction with the Decode-and-Forward DF relaying. The objective is to maximize the statistical average of the received rate per channel use at the destination. To find the optimal parameters of this code, we first formulate the problem for a two-hop scenario and describe the code design algorithm for this two-hop setting. The optimality of infinite-layer DF coding is also discussed for the case of two-hop networks. The result is then generalized to multi-hop scenarios. To show the superiority of the proposed scheme, we also evaluate the achievable average received rate of infinite-layer DF coding and compare it with the performance of previously known schemes. The second scenario, studied in Chapter 3, is a single-hop network in which both nodes are equipped with multiple antennas, while the channel gain changes quasi-statically and the CSI is not available at the source. The main reason for selecting this network setup is to study the transmission of video signals (compressed using a scalable video coding technique, e.g., SVC H.264/AVC) over a Multiple-Input Multiple-Output (MIMO) link. In this setup, although scalable video coding techniques compress the video signal into layers with different importance (for video reconstruction), the source cannot adapt the number of transmitted layers to the capacity of the channel (since it does not have the CSI in each time slot). An alternative approach is to always transmit all layers of the compressed video signal, but use unequal error protection for different layers. With this motivation, we focus on the design of multilayer codes for a MIMO link in which the destination is only able to perform successive decoding (not joint-decoding). In this chapter, we introduce a design rule for construction of multilayer codes for MIMO systems. We also propose a algorithm that uses this design rule to determine the parameters of the multilayer code. The performance analysis of the proposed scheme is also discussed in this chapter. In the two previous scenarios, the ambiguity of the source regarding the channel state comes from the fact that the channel gains randomly change in each transmission block and there is no feedback to notify the source about the current state of the channel. Apart from these, there are some scenarios in which the channel state is unknown at the source, even though the channel gain is fixed and the source knows its value.

This textbook takes a unified view of the fundamentals of wireless communication and explains cutting-edge concepts in a simple and intuitive way. An abundant supply of exercises make it ideal for graduate courses in electrical and computer engineering and it will also be of great interest to practising engineers.

This book presents comprehensive coverage of current and emerging multiple access, random access, and waveform design techniques for 5G wireless networks and beyond. A definitive reference for researchers in these fields, the book describes recent research from academia, industry, and standardization bodies. The book is an all-encompassing treatment of these areas addressing orthogonal multiple access and waveform design, non-orthogonal multiple access (NOMA) via power, code, and other domains, and orthogonal, non-orthogonal, and grant-free random access. The book builds its foundations on state of the art research papers, measurements, and experimental results from a variety of sources.

Intelligent Sensing and Communications for Internet of Everything introduces three application scenarios of enhanced mobile broadband (eMBB), large-scale machine connection (mMTC) and ultra reliable low latency communication (URLLC). A new communication model, namely backscatter communication (BackCom), intelligent reflector surface (IRS) and unmanned aerial vehicle (UAV) technology in Internet of Everything (IoE), is described in detail. Also focusing on millimeter wave, the book discusses the potential application of terahertz 6G network spectrum in the Internet of Things (IoT). Finally, the applications of IoE network in big data, artificial intelligence (AI) technology and fog/edge computing technology are proposed. Systematically introduces the technical standards and market analysis of 5G's three application scenarios, as well as the problems and challenges faced Provides readers with the knowledge of spectrum energy efficiency and cost-effective IoE network solutions Introduces the application of physical layer related technologies to the IoT, such as BackCom, IRS and UAV relay in IoE, and millimeter wave technology Discusses the potential application of terahertz 6G network spectrum in the IoT

em style="mso-bidi-font-style: normal;"Wireless Information and Power Transfer offers an authoritative and comprehensive guide to the theory, models, techniques, implementation and application of wireless information and power transfer (WIPT) in energy-constrained wireless communication networks. With contributions from an international panel of experts, this important resource covers the various aspects of WIPT systems such as, system modeling, physical layer techniques, resource allocation and performance analysis. The contributors also explore targeted research problems typically encountered when designing WIPT systems.

This book provides an accessible and comprehensive tutorial on the key enabling technologies for 5G and beyond, covering both the fundamentals and the state-of-the-art 5G standards. The book begins with a historical overview of the evolution of cellular technologies and addresses the questions on why 5G and what is 5G. Following this, six tutorial chapters describe the fundamental technology components for 5G and beyond. These include modern advancements in channel coding, multiple access, massive multiple-input and multiple-output (MIMO), network densification, unmanned aerial vehicle enabled cellular networks, and 6G wireless systems. The second part of this book consists of five chapters that introduce the basics of 5G New Radio (NR) standards developed by 3GPP. These include 5G architecture, protocols, and physical layer aspects. The third part of this book provides an overview of the key 5G NR evolution directions. These directions include ultra-reliable low-latency communication (URLLC) enhancements, operation in unlicensed spectrum, positioning, integrated access and backhaul, air-to-ground communication, and non-terrestrial networks with satellite communication.

This book studies the vulnerability of wireless communications under line-of-sight (LoS) and non-LoS correlated fading environments. The authors theoretically and practically provide physical layer security analyses for several technologies and networks such as Fifth-Generation (5G) networks, Internet of Things (IoT) applications, and Non-orthogonal multiple access (NOMA). The authors have provided these under various practical scenarios, and developed theoretical aspects to validate their proposed applications. Presents physical layer security (PLS) under correlated fading environments, 5G wireless networks, and NOMA networks; Provides end-to-end analyses, combination of channel correlation and outdated CSI and their effects on PL; Includes contributions of PLS research written by global experts in academia and industry.

Surveys general results on multiple-access channels, and gives an overview of the problems of CDMA solutions. This work includes chapters devoted to the information-theoretical aspects of multiple-access communication. It discusses multiple-access techniques and covers coding techniques.