The proliferation of connected embedded devices has driven wireless communications into commercial, military, industrial, and personal systems. It is unreasonable to expect privacy and security to be inherent in these networks given the spatial density of these devices, limited spectral resources, and the broadcast nature of wireless communications systems. Communications for these systems must have sufficient information capacity and secrecy capacity while typically maintaining small size, light weight, and minimized power consumption. With increasing crowding of the electromagnetic spectrum, interference must be leveraged as an available resource. This work develops a new beamforming method for direction-dependent modulation that provides wireless communications devices with enhanced physical layer security and the ability to simultaneously communicate and harvest energy by exploiting co-channel interference. We propose a method that optimizes a set of time-varying array steering vectors to enable direction-dependent modulation, thus exploiting a new degree of freedom in the space-time-frequency paradigm. We formulate steering vector selection as a convex optimization problem for rapid computation given arbitrarily positioned array antenna elements. We show that this method allows us to spectrally separate co-channel interference from an information-bearing signal in the analog domain, enabling the energy from the interference to be diverted for harvesting during the digitization and decoding of the information-bearing signal. We also show that this method provides wireless communications devices with not only enhanced information capacity, but also enhanced secrecy capacity in a broadcast channel. By using the proposed method, we can increase the overall channel capacity in a broadcast system beyond the current state-of-the-art for wireless broadcast channels, which is based on static coding techniques. Further, we also increase the overall secrecy capacity of the system by enabling secrecy for each user in the system. In practical terms, this results in higher-rate, confidential messages delivered to multiple devices in a broadcast channel for a given power constraint. Finally, we corroborate these claims with simulation and experimental results for the proposed method. / PHD / The proliferation of connected devices has driven wireless communications into commercial, military, industrial, and personal systems. It is unreasonable to expect privacy and security to be inherent in these networks given the spatial density of these devices, limited available resources, and the broadcast nature of wireless communications systems. Communications for these systems need not only sufficient information capacity, but also the assurance that the available information capacity remains confidential while typically maintaining small size, light weight, and minimized power consumption. With increasing crowding of the electromagnetic spectrum due to the numerous connected devices, interference between them must be leveraged as an available resource. This work develops a new method for electrically steering an array of antennas to overlay or encode information onto a signal in a way that is direction-dependent and provides wireless communications devices with enhanced security and the ability to simultaneously communicate and harvest energy from interfering devices. We propose a method that optimizes a set of time-varying array steering vectors to enable direction-dependent modulation, thus exploiting a new degree of freedom in the traditional space-time-frequency paradigm. We formulate the selection of steering vectors as a convex optimization problem for rapid computation given arbitrarily positioned array antenna elements in three dimensions. We show that this method allows us to separate interference from an information-bearing signal in the analog domain, enabling the energy from the interference to be diverted for harvesting during the digitization and decoding of the information-bearing signal. We also show that this method provides broadcast wireless communications devices with not only increased information capacity, but also assured secrecy. By using the proposed time-varying method, we can increase the overall channel capacity in a broadcast system beyond the current state-of-the-art, which is based on static encoding techniques. Further, we also increase the overall secrecy capacity of the system by ensuring that each user in the system receives separate and confidential signals. In practical terms, this results in higher-rate, confidential messages delivered to multiple devices in a broadcast channel for a given power constraint. Finally, we corroborate these claims with simulation and experimental results for the proposed method.

No / Beamforming is used to achieve diversity gain. It is a technique in diversity to remedy power penalty due to channel fading. The beam-weights for multi-antenna system are evaluated for two different approaches. These weights are then used to weight the signal beams of each transmit antenna branch. Results reveal that by exploiting the transmit channel substructures exposed by the singular vector decomposition algorithm, the capacity of a multi-antenna system can be enhanced.

This master thesis aimed to gain knowledge about the field of "adaptive array antenna systems for mobile satellite communication" and develop algorithms to control hardware equipment. We were able to set up and configure a beamformer to receive radio frequency (RF) signals using an array antenna. To do this we tested several development environments before settling on Python script programming using the Thonny editor. We created several plots of antenna patterns using both rectangular and polar coordinate systems, and developed Python code to generate animations and vector figures of the results. We also used different algorithms to control the pointing direction of the array antenna and examine the RF signal strength under various conditions. The results of our work can be used in future research to increase the robustness and flexibility of satellite communication and help provide redundancy against communication disruptions. To apply the findings of this master thesis more closely to a real-life application, we suggest using an field-programmable gate array (FPGA) to calculate and control beamforming, as the Raspberry Pi 4 computer used in this project is too slow for real-time processing. We also recommend using 2D-arrays instead of the 1D-array used in this project, which would allow for control of the beam lobe in both azimuth and elevation. Another suggestion is to build smaller blocks of 2D-array antennas connected with synchronized clocks into larger antenna arrays, which would result in improved performance. This was a challenging and rewarding project that provided valuable insights into a topic with many potential future applications within e.g. satellite communications, radar technology and mobile telephony.

Multi-antenna systems with resource allocation based on transmit and receive precoding matrices have proven to enhance the spectral efficiency of cellular systems. In this thesis, we extend these concepts to a spectrum sharing system with primary users and secondary users. The spectrum sharing area is modeled as an array of transmit and receive antennas, with the transmit power constraint defined as a function of the interference threshold of the primary user. The area covered by a database enabled spectrum access system is represented as spatial bins, which are regions of predefined sizes. Each bin is assumed to have a single secondary user base station and all the resources of that bin (i.e., available frequencies, transmit power, etc.) are consumed by this secondary user in that bin. With these assumptions, the service area of the database can be represented by a grid of secondary users. Such a grid of secondary users forms a array of transmit antennas with secondary users in each bin. Furthermore, the set of bins with its secondary users at the edge of the exclusion zone of the primary user are assumed to create an array of receive antennas. These receive antennas act as sensors that will measure the interference power at the edge of the exclusion zone of the primary users. So the overall system of secondary user base station transmit and receive antennas can be modeled as a multi-element antenna array system. A regulatory interference threshold (I_th) is defined for protection of the primary user at the edge of exclusion zones. This interference threshold is used by the resource allocation algorithms in the spectrum access system to calculate the transmit and receive precoding matrices for the secondary user antenna array. Using multiple-input multiple-output theory, the receive antenna array will measure the interference from the transmit antenna array and a feedback mechanism will update the resource allocation to keep the power at the receive array below the interference threshold of the primary user. For each array, the transmit/receive matrix is a beamforming vector which consists of a set of weights, one for each antenna. Furthermore, a codebook-based strategy is used by the spectrum access system database to choose a transmit matrix from the codebook which minimizes the interference at the primary user. The overall spectrum sharing system can be represented by a model based on four design parameters, namely, Δ = (I_th, P, V, B), where P is the transmit power constraint, V are the transmit and receive beamforming matrices, and B is the matrix with active secondary user base stations of the antenna array or the quality of service level of the secondary users. The Δ parameter is called the system index of the spectrum sharing system. We apply the multi-antenna model to the challenging problem of spectrum sharing where the primary users operational parameters, such as transmit power levels, waveform types, and service modes, can change with time. Moreover, there are several types of primary users in different bands. Most of these users are federal government systems and their operational parameters are not available to the spectrum access system database. Our framework is useful in sharing spectrum with federal primary users, since only the interference threshold is needed for sharing their bands. Furthermore, we quantify the uncertainty in the availability of these bands for secondary users and the variations in achievable capacity with sharing spectrum in these bands. / Ph. D. / The goal of this thesis is to build a Protected Shared Access Model (PSAM) [1] through database enabled Spectrum Access System (SAS). A model for the SAS is proposed, which is based on our vision for the SAS as a more dynamic and responsive architecture as a geolocation database than the current TVWS database. Major functions and capabilities of the model include, calculations of exclusion zone (EZ) of primary users with different operational parameters, use interference estimation techniques for predicting interference levels that will be generated by the new secondary users (SUs) and existing systems operating in the database service area, allocate location based transmit power levels and provide an algorithm for communications among the PUs, SUs, and the SAS to implement management and authorization framework of spectrum resources to different types of SUs. The selection of a propagation model is of utmost importance in spectrum sharing studies. Existing literature on EZs with simplified propagation models does not consider the effect of LOS interference between the PU to SU link and SU to PU link on peak points in the terrain area around the PU. The use of a terrain profile based model captures the essence of propagation over irregular terrain. Terrain regions that are far away from the PU may have a LOS between the PU and SU. So its not only the nearest area where the PU/SU can get interference, but interference is present from areas further away on high grounds having a direct LOS with the PU antenna. The exclusion zone computation with terrain profile based propagation model captures this effect, and it is the same effect that makes the shape of the exclusion zone irregular. So the propagation model used in spectrum sharing studies must be able to use the terrain for the specific geographical area for precise propagation calculations, and provide statistical reliability parameters for the computed propagation values for area of interest. For a multi-tier shared access model with incumbent access (IA) users, priority access (PA) users and general authorized access (GAA) users. The SU interference tolerance thresholds varies by the type of SU’s i-e., PA users like public safety systems and mission critical users have low tolerance for interference and hence need to operate further from the PU. While GAA users like commercial broadband systems have higher interference tolerances and can operate closer to the PU. This multi-tier shared access model requires varying levels of interference protection from PU, that can be provided with multiple exclusion zones [2] defined for different types of SU’s. We propose the concept of <i>differential spectrum access hierarchy</i>, and define it in the context of a multi-tiered EZs that are based on quantiles of tolerable interference levels for different tiers of SUs. We also quantify and show the gain in SU capacity (or throughput) obtained by using multi-tiered EZs for different tiers of SUs. Using simulation results, we show that the size of EZs can be significantly reduced with the use of a terrain profile-based propagation model that takes into account terrain profile for signal attenuation between PUs and SUs in the P2P link. The exclusion zones involve the use of interference test points at the circumference of the protection contour of the PU. They are monitoring test points that the SAS uses with a propagation model and locations of SUs to calculate interference [3]. Consider a model of Figure 5.1, the coexistence environment with PU, SU and the SAS with a database. As more SUs enter the system, their transmit powers creates interference for the PUs. In the event of SU interference exceeding a predefined threshold level at any of the test points, the SAS uses an interference based power control algorithm to turnoff the nearest dominant interferer’s. Turning off the dominant interferers eliminates interference generated by that node at the PU. This nearest node interference cancellation significantly reduces the outage probability at the PU. Unlike existing metrics for spectrum utilization efficiency that considers separate metrics for PU interference protection and maximum use of the band for secondary use [4] [5]’we define a new metric for spectrum utilization efficiency. This metric uses utility functions and cost functions to measure the impact of secondary use of the spectrum on PUs as well as the degree of satisfaction SUs can achieve from reuse of such spectrum [6]. The new spectrum utilization metric is used to evaluate tradeoffs between interference protection of PUs and SU spectrum utilization.

Passive acoustic systems composed of hydrophone array have been shown useful for underwater acoustic source detection and tracking. The work presented here demonstrates use of a passive acoustic system for an Autonomous Underwater Vehicle (AUV) composed of a 2D hydrophone array along with a post processing algorithm for real time detection and tracking of surface vessels. Important design decisions for development of the hydrophone array are taken based on different factors such as the frequency range of broadband surface vessel noise, review of literature, financial as well as structural constraints of the AUV. The post-processing algorithm, developed using a phased array principle called acoustic beamforming, outputs real-time heading angles of the target surface vessels. Initial measurements conducted at Claytor Lake with the developed passive acoustic system to locate a white noise acoustic source showed better performance with functional beamforming technique among others. Various hydrophone array configurations are tested during these measurements to determine the optimal hydrophone placement. Furthermore, field tests are conducted at Norfolk Bay area to assess the performance of the developed system to real time detect and track surface vessels of different sizes in mission relevant environment. Cross-spectral matrix subtraction approach to subtract AUV's self noise is investigated to improve signal range and thus the detection range of these different surface vessels. This approach showed improvement in detection range of up to 350%. Another set of measurements again at Claytor Lake demonstrates real time detection and tracking of a small boat using an AUV integrated with the developed passive acoustic system operating at different propeller conditions. Results showed that low signal to noise ratio at higher AUV propeller rpm makes the detection and tracking difficult limiting the operating AUV propeller rpm up to 1500. This work also explores custom build hydrophones based on piezoelectric material of different shapes and sized to replace the expensive industry purchased hydrophones to lower the cost of developed system. / Master of Science / In field of underwater acoustic, hydrophone arrays have gained popularity for the detection and tracking of sound sources by just listening to them. This study presents design, development and testing of such hydrophone array attached to an AUV for real time detection and tracking of surface vessels. Multiple hydrophones in an array collect the underwater noise radiated by the target surface vessel which are essentially the unsteady pressure fluctuations. The phase difference between signals acquired by different hydrophones is then used to predict the direction of arrival of a sound wave from the target ship. Such a phased array principle called acoustic beamforming is used to develop a post processing algorithm which takes hydrophone array signals as input and outputs the heading angle of the target ship. This work first demonstrates capability of the developed hydrophone array and the algorithm to detect a white noise acoustic source (speaker) placed inside water at Claytor Lake. These measurements investigated performance of different acoustic beamforming techniques as well as different hydrophone array configurations. Furthermore, measurements conducted with actual surface vessel at Norfolk Bay area proved capability of the developed hydrophone array and the algorithm to detect and track ships in real time. The performance of the hydrophone array is characterized in terms of detection range and was observed to improve by 350% when the AUV's self noise is removed from the acquired hydrophone signals. Combined single unit of AUV and developed hydrophone array system also demonstrated real time detection and tracking of a small boat at Claytor Lake for different AUV operating conditions. Moreover, custom build hydrophones manufactured using piezoelectric material are found to be a feasible replacement for the expensive industry purchased hydrophones in order to reduce cost of the array.

Dans cette thèse, des méthodes de caractérisation acoustique passive et active de systèmes acoustiques à deux ports sont présentées, basées sur une décomposition d’ondes planes en entrée et sortie. Cette décomposition est réalisée par la méthode du beamforming. Ces méthodes mises en place et validées sur des géométries simples, sont ensuite employées pour caractériser l’étage compresseur d’un turbocompresseur de suralimentation automobile. La caractérisation acoustique active se fait par la mesure de la puissance et de l’intensité acoustique dans les conduits du compresseur, ceci pour des points de fonctionnement spécifiques, des cartographies compresseur complètes sont également élaborées. Les essais ont été menés sur banc turbo, banc moteur et sur véhicule complet. La caractérisation acoustique passive est abordée par le calcul de matrices du compresseur (matrice de transfert, matrice d’impédance et matrice de diffusion). Le calcul de la perte par transmission acoustique est déduit de ces matrices. Des essais ont été réalisés et comparés à des simulations éléments finis 3D sur un turbocompresseur statique comme sur un turbocompresseur opérationnel. / In this thesis, methodologies to perform the acoustic passive and active characterization of two port systems are presented. These methods are based on plane wave decomposition made at the inlet and at the outlet of the system. This decomposition is made according beamforming technique. Once these methods were validated on simple geometries, they were then applied to the compressor stage of an automotive turbocharger. The active acoustic characterization is made by the measurement of the acoustic power and acoustic intensity in the compressor ducts on given working points, but also on complete compressor maps. This was performed on turbocharger benches, engine benches and a complete vehicle. The passive acoustic characterization is made by the calculation of characteristic matrices (transfer matrix, impedance matrix and scattering matrix). These matrices are then used to compute the acoustic transmission loss. Experiments were performed on a static turbocharger and compared to 3D finite elements simulations, as well as experiments on an operating turbocharger.

Adaptive beamforming is a. powerful approach to receive or transmit signals of interest in a spatially selective way in the presence of interference and noise. Recently, there has been renewed interest in adaptive beamforming driven by applications in wireless communications, where multiple-input multiple-output (MEMO) techniques have emerged as one of the key technologies to accommodate the high number of users as well as the increasing demand for new high data rate services. Beamforming techniques promise to increase the spectral efficiency of next generation wireless systems and are currently being incorporated in future industry standards. Although a significant amount of research has focused on theoretical capacity analysis, little is known about the performance of such systems in practice. In thesis, I experimentally and analytically evaluate the performance of adaptive beamforming techniques on the downlink channel of a wireless LAN. To this end. I present the design and implementation of the first multi-user beam-forming system and experimental framework for wireless LANs. Next, I evaluate the benefits of such system in two applications. First, I investigate the potential of beamforming to increase the unicast throughput through spatial multiplexing. Using extensive measurements in an indoor environment, I evaluate the impact of user separation distance, user selection, and user population size on the multiplexing gains of multi-user beamforming. I also evaluate the impact of outdated channel information due to mobility and environmental variation on the multiplexing gains of multi-user beamforming. Further, I investigate the potential of beamforming to eliminate interference at unwanted locations and thus increase spatial reuse. Second, I investigate the potential of adaptive beamforming for efficient wireless multicasting. I address the joint problem of adaptive beamformer design at the PHY layer and client scheduling at the MAC layer by proposing efficient algorithms that are amenable to practical implementation. Next, I present the implementation of the beamforming based multicast system on the WARP platform and compare its performance against that of omni-directional and switched beamforming based multicast. Finally, I evaluate the performance of multicast beamforming under client mobility and infrequent channel feedback, and propose solutions that increase its robustness to channel dynamics.

The high amount of scientific and communications data produced by low earth orbiting satellites necessitates economical methods of communication with these satellites. A volumetric phased array for demonstrating horizon-to-horizon electronic tracking of the NASA satellite EO-1 was developed and demonstrated. As a part of this research, methods of optimizing the elemental antenna as well as the antenna on-board the satellite were investigated. Using these optimized antennas removes the variations in received signal strength that are due to the angularly dependent propagation loss exhibited by the communications link. An exhaustive study using genetic algorithms characterized two antenna architectures, and included optimizations for radiation pattern, bandwidth, impedance, and polarization. Eleven antennas were constructed and their measured characteristics were compared to those of the simulated antennas. Additional studies were conducted regarding the optimization of aperiodic arrays. A pattern-space representation of volumetric arrays was developed and used with a novel tracking algorithm for these arrays. This algorithm allows high-resolution direction finding using a small number of antennas while mitigating aliasing ambiguities. Finally, a method of efficiently applying multiple beam synthesis using the Fast Fourier Transform to aperiodic arrays was developed. This algorithm enables the operation of phased arrays combining the benefits of aperiodic element position with the efficiency of FFT multiple beam synthesis. Results of this research are presented along with the characteristics of the volumetric array used to track EO-1. Experimental data and the interpretations of that data are presented, and possible areas of future research are discussed.

Afin de répondre à la demande croissante du nombre d'objets connectés et de débits de données plus élevés, la cinquième génération de réseau mobile (5G) va être déployée.Pour répondre à ces défis, la 5G utilisera le beamforming pour améliorer la qualité de transmission et étendre la couverture du réseau. En raison du manque de spectre RF disponible en dessous de 6 GHz, l'industrie de la téléphonie mobile étudie actuellement les bandes de fréquences millimétriques en particulier autour de 28 GHz. L'utilisation de la technologie CMOS pour les applications 5G apparait prometteuse pour le marché de masse que vise la 5G, d'autant qu'aujourd'hui la miniaturisation des transistors CMOS permet un fonctionnement compétitif aux fréquences millimétriques. Pour répondre à toutes les attentes de la 5G notamment en termes de fiabilité, de nouvelles idées en rupture, avec le self-healing et le self-contained, permettent d’utiliser au maximum les avantages de la technologie CMOS tout en proposant un fonctionnement fiable pou rl’amplificateur. Dans le cadre du self-healing et du self-contained, plusieurs circuits son tintégrés sur silicium tel qu'un amplificateur intégrant un détecteur de puissance totalement non invasif pour le self-healing et un amplificateur équilibré pour le selfcontained. / In order to meet the growing demand for more connected objects and higher data rates,the fifth generation of mobile network (5G) will be deployed. To address thesechallenges, the 5G will use beamforming to improve the transmission quality and extendthe network coverage. Due to the lack of available RF spectrum below 6 GHz, the mobileindustry is studying millimeter wave frequency bands in particular around 28 GHz. Theuse of CMOS technology for 5G applications is promising for the 5G mass market,especially nowadays the miniaturization of CMOS transistors allows competitiveoperation at millimeter frequencies. To meet all the expectations of the 5G especially interms of reliability, new breakthrough ideas, with the self-healing and the selfcontained,allow to use all the benefits of CMOS technology to the maximum whileoffering reliable operation for the amplifier. Within the framework of self-healing andself-contained, several circuits are integrated on silicon such as an amplifier integratedwith a totally non-invasive power detector for self-healing and a balanced self-containedamplifier.

La recherche effectuée dans cette thèse a pour cadre les réseaux radio privés dédiés aux forces de sécurité civile. En effet, doté actuellement d’un service bande étroite, ils doivent évoluer pour faire face à de nouveaux besoins comme la vidéo ou le multimédia. L’objectif est donc d’adapter la technologie LTE aux contraintes et propriétés de ces réseaux particulier. Ainsi, le nombre d’utilisateurs est limité mais le service doit toujours être disponible et des priorités peuvent être mises en œuvre.Dans ce contexte, l’allocation des ressources de communication est un problème important avec des prérequis différents des réseaux d’opérateurs. Notre conception d’algorithmes d’allocation a donc été menée avec deux objectifs principaux : maximiser l'efficacité du spectre et servir équitablement les utilisateurs au lieu de maximiser le débit global du réseau.Cette thèse propose des nouvelles stratégies de l’allocation des blocs de ressources (RB) dans les systèmes LTE sur le lien descendant. Au contraire des algorithmes classiques d'allocation des ressources qui se basent sur la capacité de RB déjà estimée, nos stratégies d’allocation des RB cherchent à améliorer le débit utilisateur, en utilisant la coopération à base de Beamforming et les modèles de la théorie des jeux.1. L’interférence inter-cellulaire est le principal problème des systèmes OFDMA. Grâce aux antennes MIMO (Multiple-Input-Multiple-Output), la technique de Beamforming améliore le signal reçu afin d'augmenter le SINR (Signal-to-Interference-plus-Noise-Ratio), mais le signal amélioré peut également influencer l’interférence inter-cellulaire dans les cellules voisines. Dans les méthodes traditionnelles, le contrôleur alloue les RBs aux UEs (User Equipement) en fonction de la capacité des RB et d'autres paramètres, le système applique alors la technique de Beamforming aux équipements utilisateurs choisis. Après la formation des faisceaux, la capacité des RB varie mais l'ordonnanceur conserve la même allocation. Au contraire, notre système alloue les RBs et choisit les vecteurs de Beamforming conjointement pour améliorer les performances de la technique de Beamforming. Il accroît le débit moyen en augmentant la capacité moyenne du RB. Comme plusieurs paramètres sont pris en compte, la complexité augmente exponentiellement aussi. Dans cette thèse, nous avons développé une méthode itérative pour réduire la complexité. Notamment, elle améliore de plus de 10% le débit des utilisateurs en bord de la cellule.2. Contrairement aux performances des algorithmes qui maximisent le débit global du réseau, les approches d’allocation de ressources à base de théorie des jeux maximisent la fonction d'utilité des UE du point de vue économique. Si le modèle a une solution NBS (Nash Bargaining Solution) il offre une solution optimale de Pareto de la fonction d'utilité. L’allocation traditionnelle est d'optimiser l'allocation de sous-porteuses à chaque intervalle de temps, mais dans le système OFDMA, les sous-porteuses sont formées de RBs dans le temps. Nous proposons une approche RB NBS, qui est plus efficace que les schémas existants. Nous analysons les canaux de fast-fading et les comparons sans l'influence de l’atténuation. En raison de la grande atténuation de signal en bordure de la cellule, l’utilisateur a toujours des RB de plus faible capacité que celui au centre de la cellule. Notre idée est d'ajouter un facteur de compensation pour combattre l'influence de la perte de propagation. Les facteurs de compensation sont soigneusement choisis afin de maximiser la fonction NBS. Cependant, le calcul de ces facteurs a une grande complexité et nous développons quatre solutions approchées qui donnent les mêmes performances avec une bonne précision. L'évaluation des performances de notre approche confirme que notre méthode et ses solutions approchées sont capables de partager équitablement les ressources sur toute la cellule. / This research takes place in the context of Private Mobile Radio networks evolution which aims at designing a new LTE based PMR technology dedicated to public security services. As the frequency bands dedicated to this service is scarce and the need of public safety forces is different, we have revisited the Resource Allocation problem in this thesis with two main objectives: designing new allocation algorithms which outperform the spectrum efficiency and serving fairly the users instead of maximizing the global network throughput.This thesis proposes new Resource Block (RB) allocation strategies in LTE downlink systems. Instead of the well-known resource allocation algorithms, which work on the condition that the RB capacity is already estimated, our RB allocation schemes can improve the potential of the channel capacity, using Beamforming cooperation and game-theoretical problems1. With the MIMO (Multiple-Input-Multiple-output) antennas, the Beamforming technique improves the received signal in order to increase the SINR (Signal-to-Interference-plus-Noise-Ratio), but the improved signal may also influence the inter-cell interference in the neighbouring cells. As inter-cell interference is the main interference in the OFDMA system, a smart scheduling can choose UEs (User Equipment) in adjacent cells to control interference increment caused by Beamforming.In traditional methods, the scheduler allocates RBs to UEs depending on the RB capacities and other parameters, the system then applies the Beamforming technique to these chosen UEs. After the Beamforming, the RB capacity varies but the scheduler keeps the same allocation.Our scheme allocates the RBs and chooses Beamforming vectors at the same time to enhance the performance of the Beamforming technique. It increases the average throughput by increasing the RB’s average capacity. Because more parameters are taken into account, the complexity also increases exponentially. In the thesis we find an iterative method to reduce the complexity. From the simulations, our iterative method also has good performance and improves more than 10% of throughput on the cell edge.2. In contrast to the performance first algorithms, game theoretic allocation schemes maximize the UEs’ utility function from the economical point of view. The NBS (Nash Bargaining Solution) offers a Pareto optimal solution for the utility function.The traditional NBS allocation in an OFDMA system is to optimize the subcarrier allocation at each time slot, but in the OFDMA system, the subcarriers are composed of Resource Blocks (RB) in time series. We propose an RB NBS approach, which is more efficient than the existing subcarrier NBS allocation scheme.We analyze the fast-fading channels and compare them without the path-loss influence. Because of the great path-loss in cell edge, the edge UE always has lower RB capacity than the cell center UE. Our idea is to bring in a compensating factor to overcome this path-loss influence, and the compensating factors are carefully chosen to maximize the NBS function. However, the computation of these factors has a high complexity and we develop four approximated solutions which give same performance and accuracy. The performance evaluation confirms that our method and its approximated solutions are able to spread resources fairly over the entire cell.