Vehicular ad hoc networks (VANETs) will require improved communications, especially for critical scenarios. The improvement of these communications will be more crucial in dense urban environments where urban air mobility (UAM) is expected to witness significant growth during the next decade. We propose the use of networked tethered flying platforms (NTFPs) to enhance VANET communications. NTFPs are unmanned aerial platforms that are secured to the ground via a tether that supplies the platform with continuous power and data. To improve the spectral efficiency of communications, we implement non-orthogonal multiple access (NOMA) scheme. Additionally, to increase the bandwidth and data rates of communications, we use millimeter-wave (mmWave) frequencies. In UAM, NTFPs will coexist with other flying platforms, such as unmanned aerial vehicles (UAVs) and electric vertical takeoff and landing (eVTOL) aircraft. Hence, we study the performance of vehicular communications in the presence of interfering UAVs/eVTOLs and other road vehicles, and we compare the use of NTFPs with traditional terrestrial roadside units (RSUs).

This thesis focuses a noncoherent two-user uplink system with each user having a single antenna and a base station equipped with a large number of antennas. It is assumed that small scale channel fading is Rayleigh fading and varies in every one time slot. For such massive MIMO uplink system, we consider an optimal finite-alphabet non-orthogonal multiple access (NOMA) design with each user utilizing nonnegative binary modulation. A fast noncoherent maximum likelihood (ML) detection algorithm for the sum constellation of the two users and a corresponding closed form symbol error probability (SEP) formula are derived. In addition, the lower and upper bounds on SEP are established to quantitatively characterize how quickly SEP decays when the number of base station antennas goes to infinity. Two important concepts: full receiver diversity and geometrical coding gain, are introduced. Particularly for two users and three users systems, with each user transmitting nonnegative binary constellation, we obtain an optimal closed form sum constellation that maximizes both the receiver diversity gain and geometrical coding gain. Computer simulations validateour theoretical analysis and demonstrate that our proposed optimal constellation attains significant performance gains over the currently available constellation design for the same massive MIMO upink system.\ Our future work is to develop an algorithm for devising an optimal AUDCG for the considered system in a more general case. / Thesis / Master of Applied Science (MASc)

It is unmistakable that sport is a universally vital element in our society today. Sport teaches us teamwork, sportsmanship, and provides a stage to compete instead of fight. Sport has been known to end civil wars and bring peace when all hope is lost. Sport has been called the world's first global culture. It has been said that where the crowds gather, history is made. With stadiums providing a stage for over 100,000 people at one time, it is easy to associate a stadium with this thought. Since the function that stadiums hold is so important to us as people, shouldn't our stadiums reflect the importance of the function they represent? / Master of Architecture

In this thesis, we consider maximized power allocation of non-orthogonal multiple ac- cess (NOMA) schemes since it outperforms than orthogonal multiple access (OMA) for the high altitude platform networks (HAPNETs) both in the back- haul and access links. Secondly, we propose a cluster formation (CF) algorithm and power-bandwidth resource allocation (PB-RA) for solving the resource management of HAPNETs. We adopt the particle swarm optimization (PSO) algorithm to explore the optimal de- ployment of high altitude platforms (HAPs) and unmanned aerial vehicles (UAVs) iteratively by a given swarm size. By PSO, we provide the best deployment under a given iteration number. Besides that, numerical results show that the NOMA schemes have better performance than OMA ones concerning different network control factors like the number of BSs, HAPs, and UAVs.

In our thesis work, we analyze the performance analysis of a power domain NonOrthogonal Multiple Access (NOMA) system in which the closer user acts as fullduplex relaying to forward the signal to farther user. Because Nakagami-m distribution is a generalized case including the two common fading distributions as specialcases: Rayleigh distribution (m=1), Rician distribution (m>1). We assume that thesystem experiences Nakagami-m fading. Then, we have to analyze outage probabilityof NOMA system. Numerical results are provided for outage probability to show theeffect of system parameters on the performance of the NOMA system in full duplexrelaying over Nakagami-m fading.

The recent developments in Internet-of-Things (IoT) and the next-generation wireless communication systems (5G and beyond) are posing unprecedented demands for massive connectivity, enhanced spectrum efficiency, and strengthened reliability. Moreover, the conventional orthogonal multiple access (OMA) techniques have approached their fundamental limits or the improvements in performance are marginal. To this end, a paradigm-shift from OMA to massive multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) technology is proposed. The proposed techniques are capable of serving multiple spatially-distributed user nodes/IoTs in the same frequency-time resource block by reaping out the benefits of power-domain NOMA, and favorable propagation and channel hardening brought by very large antenna arrays.First, a comprehensively literature survey has been conducted. Next, system, channel and signal models were developed by considering practical transmission impairments of the proposed massive MIMO NOMA. Then, novel NOMA relaying strategies via massive MIMO with pilot designs, per-hop and cascaded channel estimation, statistical-parameter based power allocation policy, and reliable precoding scheme are designed. Then, a complete analytical framework to derive the fundamental performance metrics is developed. A MATLAB-based simulation framework is developed to verify the proposed system designs.Then, the detrimental effects of residual interference caused by intra-cluster pilot sharing and error propagation caused by imperfect successive interference cancellation are quantified. The results acquired can provide insights for refining the proposed techniques in terms of signal model and pilot design.Trade-offs among massive connectivity and spectral efficiency will be established and refined for the proposed relay aided/cell-free massive MIMO NOMA via carefully designing per-hop and cascaded channel estimation, low-complexity statistical-parameter-based power allocation, and conjugate precoding schemes. The proposed technique is expected to significantly outperform the conventional OMA scheme in all overloaded system scenarios by virtue of the proposed aggressive spatial multiplexing and power-domain NOMA techniques. Hence, the proposed technique can simultaneously serve many users with fast data rates than that of the existing OMA techniques. The proposed NOMA techniques are expected to provide higher spectral and energy efficiencies with ultra-low end-to-end latency than those of existing OMA. Thus, the proposed relay-aided/cell-free massive MIMO NOMA can significantly contribute as a novel candidate technology for the next-generation wireless standards.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves 249-268).

As the complexity of modern cellular networks continuously increases along with the evolution of technologies and the quick explosion of mobile data traffic, conventional large scale system level simulations and analytical tools become either too complicated or less tractable and accurate. Therefore, novel analytical models are actively pursued. In recent years, stochastic geometry models have been recognized as powerful tools to analyze the key performance metrics of cellular networks. In this dissertation, stochastic geometry based analytical models are developed to analyze the performance of some key technologies proposed for 5G mobile networks. Particularly, Device-to-Device (D2D) communication, Non-orthogonal multiple access (NOMA), and ultra-dense networks (UDNs) are investigated and analyzed by stochastic geometry models, more specifically, Poisson Point Process (PPP) models. D2D communication enables direct communication between mobile users in proximity to each other bypassing base station (BS). Embedding D2D communication into existing cellular networks brings many benefits such as improving spectrum efficiency, decreasing power energy consumption, and enabling novel location-based services. However, these benefits may not be fully exploited if the co-channel interference among D2D users and cellular users is not properly tackled. In this dissertation, various frequency reuse and power control schemes are proposed, aiming at mitigating the interference between D2D users and conventional cellular users. The performance gain of proposed schemes is analyzed on a system modeled by a 2-tier PPP and validated by numerical simulations. NOMA is a promising radio access technology for 5G cellular networks. Different with widely applied orthogonal multiple access (OMA) such as orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA), NOMA allows multiple users to use the same frequency/time resource and offers many advantages such as improving spectral efficiency, enhancing connectivity, providing higher cell-edge throughput, and reducing transmission latency. Although some initial performance analysis has been done on NOMA with single cell scenario, the system level performance of NOMA in a multi-cell scenario is not investigated in existing work. In this dissertation, analytical frameworks are developed to evaluate the performance of a wireless network with NOMA on both downlink and uplink. Distinguished from existing publications on NOMA, the framework developed in this dissertation is the first one that takes inter-cell interference into consideration. UDN is another key technology for 5G wireless networks to achieve high capacity and coverage. Due to the existence of line-of-sight (LoS)/non-line-of-sight (NLoS) propagation and bounded path loss behavior in UDN networks, the tractability of the original PPP model diminishes when analyzing the performance of UDNs. Therefore, a dominant BS (base station)-based approximation model is developed in this dissertation. By applying reasonable mathematical approximations, the tractability of the PPP model is preserved and the closed form solution can be derived. The numerical results demonstrate that the developed analytical model is accurate in a wide range of network densities. The analysis conducted in this dissertation demonstrates that stochastic geometry models can serve as powerful tools to analyze the performance of 5G technologies in a dense wireless network deployment. The frameworks developed in this dissertation provide general yet powerful analytical tools that can be readily extended to facilitate other research in wireless networks.

Avec l’émergence rapide des applications Internet, il est prévu que le trafic mobile mondial augmente de huit fois entre fin 2018 et 2022. En même temps, les futurs systèmes de communication se devront aussi d’améliorer l'efficacité spectrale des transmissions, le temps de latence et l’équité entre utilisateurs. À cette fin, une technique d’accès multiple non orthogonal (NOMA) a été récemment proposée comme un candidat prometteur pour les futurs accès radio. La technique NOMA est basée sur un nouveau domaine de multiplexage, le domaine des puissances. Elle permet la cohabitation de deux ou plusieurs utilisateurs par sous-porteuse ou sous-bande de fréquence. Cette thèse aborde plusieurs problèmes liés à l’allocation de ressources basée sur NOMA afin d'améliorer les performances du réseau en termes d'efficacité spectrale, de débit et/ou d’équité entre utilisateurs. Dans ce sens, des solutions théoriques et algorithmiques sont proposées et des résultats numériques sont obtenus afin de valider les solutions et de vérifier la capacité des algorithmes proposés à atteindre des performances optimales ou sous-optimales. Après une étude bibliographique des différentes techniques d’allocation de ressources présentée dans le premier chapitre, on propose dans le deuxième chapitre plusieurs stratégies d’allocation de ressource où une réduction de la bande utilisée par les utilisateurs est ciblée. Les résultats de simulation montrent que les stratégies proposées améliorent à la fois l’efficacité spectrale et le débit total des utilisateurs par rapport aux systèmes basés uniquement sur des techniques d’accès orthogonales. Quant au troisième chapitre, il étudie la performance du Proportional Fairness (PF) Scheduler tout en considérant que la bande passante est disponible en totalité. Dans ce sens, plusieurs améliorations basées sur le PF sont proposées, qui offrent au système NOMA des avantages en termes de débit, d’équité entre utilisateurs et de qualité de service. Dans le quatrième chapitre, nous proposons plusieurs techniques d’allocation de ressources qui donnent aux utilisateurs la possibilité de favoriser le débit par rapport à l’équité entre utilisateurs et vice versa. Dans le dernier chapitre, différentes techniques permettant une transmission hybride broadcast/broadband sur la même bande de fréquence sont proposées et comparées à l’état de l’art. / With the proliferation of Internet applications, between the end of 2016 and 2022, total mobile traffic is expected to increase by 8 times. At the same time, communications networks are required to further enhance system efficiency, latency, and user fairness. To this end, non-orthogonal multiple access (NOMA) has recently emerged as a promising candidate for future radio access. By exploiting an additional multiplexing domain, the power domain, NOMA allows the cohabitation of two or more users per subcarrier, based on the principle of signal superposition. This dissertation addresses several radio resource allocation problems in mobile communication systems, in order to improve network performance in terms of spectral efficiency, through put, or fairness. Theoretical analysis and algorithmic solutions are derived. Numerical results are obtained to validate our theoretical findings and demonstrate the algorithms ability of attaining optimal or sub-optimal solutions. To this direction, the second chapter of this thesis investigates several new strategies for the allocation of radio resources (bandwidth and transmission power) using NOMA principle, where the minimization of the total amount of used bandwidth is targeted. Extensive simulation results show that the proposed strategies for resource allocation can improve both the spectral efficiency and the cell-edge user throughput, especially when compared to schemes employing only orthogonal signaling. A context where the total bandwidth is available has also been studied, in the 3rd chapter where we investigate the performance of the proportional fairness (PF) scheduler, and we propose modifications to it, at the level of user scheduling and power allocation that show to improve the system capacity, user fairness and QoS. In the 4th chapter, we proposed new pairing metrics that allow to favor the fairness at the expense of the throughput and vice versa. The proposed metrics show enhancements at the level of system capacity, user fairness, and computational complexity. Different techniques that allow a hybrid broadcast/multicast transmission on the same frequency platform are proposed in the last chapter and compared to the state of the art.

Non-orthogonal multiple access (NOMA), with its exceptional spectrum efficiency, was thought to be a promising technology for upcoming wireless communications. Physical layer security has also been investigated to improve the security performance of the system. Power-domain NOMA has been considered for this paper, where multiple users can share the same spectrum which bases this sharing on distinct power values. Power allocation is used to allocate different power to the users based on their channel condition. Data signals of different users are superimposed on the transmitter's side, and the receiver uses successive interference cancellation (SIC) to remove the unwanted signals before decoding its own signal. There exist an eavesdropper whose motive is to eavesdrop on the confidential information that is being shared with the users. The network model developed in this way consists of two links, one of which considers the relay transmission path from the source to Near User to Far User and the other of which takes into account the direct transmission path from the source to the destination, both of which experience Nakagami-m fading. To degrade the eavesdropper's channel, the jamming technique is used against the eavesdropper where users are assumed to be in a full-duplex mode which aims to improve the security of the physical layer. Secrecy performance metrics such as secrecy outage probability, secrecy capacity, etc. are evaluated and analyzed for the considered system. Mathematical analysis and simulation using MATLAB are done to assess, analyze and visualize the system's performance in the presence of an eavesdropper when the jamming technique is applied. According to simulation results, the active jamming approach enhances the secrecy performance of the entire system and leads to a positive improvement in the secrecy rate.