In this thesis, I conduct the hardware prototyping of a two-way relay system using the National Instruments FlexRIO hardware platform. First of all, I develop several practical mechanisms to solve the critical synchronization issues of the systems, including Orthogonal Frequency-Division Multiplexing (OFDM) frame synchronization at the receiver, source to source node synchronization, and handshaking between the sources and relay nodes. Those synchronization methods control the behavior of the two source nodes and the relay node, which play critical roles in the two-way relay systems. Secondly, I develop a pilot-based channel estimation scheme and validate it by showing the successful self-interference cancellation for the two-way relay systems. In particular, I experiment the self-interference cancellation technique by using several channel estimation schemes to estimate both source to relay channels and relay to source channels. Moreover, I implement the physical layer of a 5 MHz OFDM scheme for the two-way relay system. Both the transmitter and receiver are designed to mimic the Long Term Evolution (LTE) downlink scenario. The physical layer of the transmitter has been implemented in Field-Programmable Gate Arrays (FPGAs) and executed on the hardware board, which provides high throughput and fundamental building blocks for the two-way relay system. The physical layer of receiver is implemented in the real-time controller, which provides the ?exibility to rapidly recon?gure the system. Finally, I demonstrate that the 5MHz OFDM based two-way relay system can achieve reliable communications, when the channel estimation and system synchronization can be correctly executed.

In this thesis, I demonstrate a genetic-algorithm-based optimization method for designing matching and decoupling networks (MDNs) for asymmetric two-element antenna arrays. The proposed method considers practical aspects in MDN realization by accounting for short pieces of transmission lines between the lumped elements and only using capacitor/inductor values from a predefined database of commercially available lumped component values. In addition, the proposed algorithm is able to explore all subsets of a general MDN topology in its search for a solution, providing some flexibility for system optimization (e.g., reducing the number of lumped elements used in an MDN). Details about the proposed approach along with performance analysis of four design examples based on this method are presented. One of the designs was fabricated and measured to demonstrate the effectiveness of the proposed design method. Chapter 1 provides the motivation and context for this work with relevant literature review and objectives of this thesis. Chapter 2 reviews existing MDN design techniques and discusses practical design considerations for the proposed method. Chapter 3 briefly discusses the basics of genetic algorithm (GA) and its relevance to this work. Chapter 4 presents the method proposed in my thesis work and describes how the genetic algorithm is implemented for designing MDNs for asymmetric two-element antenna arrays. Chapter 5 reports the details of four different MDN design examples along with their simulation and measurement results. Chapter 6 concludes the thesis work and discusses potential future development to further advance this work.

<p>A wireless revolution has occurred resulting in the formation of a proverbial backbone of wireless devices that our everyday functionality, productivity, and general way of life have become dependent. Consequently, victimizing an already constrained and finite wireless spectrum with further demands for increased bandwidths, greater channel capacities, and an insatiable plea for faster access rates. In-band full-duplexing (IBFD) is an innovative and encouraging technology that aims to answer this tacit mitigation call by bolstering spectral efficiency through simultaneous same frequency band transmission and reception. Conventionally, transceiver-based systems have their respective transmission and reception dictated by occurring in either disparate time slots (half-duplex) or distinct frequencies (out-of-band full-duplex). By achieving simultaneous same band communication, a theoretical doubling in spectral efficiency is rendered feasible. However, transmitter to receiver leakage, or self-interference (SI), remains the most barring frustration to IBFD realization. Being locally generated, SI is considerably stronger (often 50-100dB) than the desired signal-of-interest (SOI). Left unresolved, this unwanted energy saturates the receiver’s amplifiers and desensitizes its analog-to-digital converters. Thus, rendering the SOI unintelligible. Therefore, a means of self-interference cancellation (SIC) is necessitated to suppress any polluting SI to levels that of or below the receiver’s noise floor.</p><p></p>In this thesis an in-depth history of in-band full duplex technology is first presented, followed by a condensed examination of the SIC domains. Pertinent theory is presented pertaining to noise analysis and estimation relevant to a proposed IBFD transceiver architecture. Finally, a modelled simulation of this transceiver, developed in MATLAB, is presented. Subsequent results detailing an investigative study done on a fully adaptive tapped-branch analog self-interference canceller are shown. Said canceller’s variable phase and amplitude weights are set via real-time training using gradient descent algorithms. Evaluation of the results reveal marginal effect on the SIC efficacy due to transmission path nonlinearity and noise distortions alone. However, expansion of model consideration for conceivable cancellation hardware nonlinearities reveals an indirectly proportional degradation of SIC performance by up to 35dB as distortion levels vary from -80 dBm to -10 dBm. These results indicate consideration of such non-idealities should be an integral part of cancellation hardware design for the preclusion of any intrinsic cancellation impediments.

With the wireless technology evolving quickly, so does the demand of speed and efficiency. This makes the companies look for new and better ways to improve the current systems. One way of improving the present systems would be to employ Full Duplex Technology. In recent years the standard has been Half duplex technology with either Time Division Duplexing (TDD) or Frequency Division Duplexing (FDD). The drawback of TDD is that the signals is put in different time slots, meaning if many signals is to be transmitted at the same time there will be a delay. For FDD the signals are sent at different frequencies. This takes up a lot of space in the spectral domain. Full Duplex Technology has the potential to double the spectral efficiency with it'spower to transmit and receive signals simultaneously at the same frequency. The main challenge with Full Duplex (FD) is the leaking Self-Interference (SI) from the transmitter to the receiver. Different methods can be used to suppress the SI in both the digital and the analog domain. Typically the Self-Interference Cancellation (SIC) is split into three parts. The passive Radio Frequency (RF) SIC, which suppresses the signal using for example. antenna separation, antenna polarization or a circulator. The active analog RF cancellation which could for example use a multi-tap analog least mean square adaptive and finally the Digital passband SIC, that is addressed in this thesis. The cancellation in the RF domain needs to suppress enough for the Low Noise Amplifier (LNA) and the Analog to Digital Converter (ADC) to not saturate. The Digital SIC should optimally suppress the signal to the noise floor to be able to demodulate the received signal. In this thesis modelling and reconstruction of the SI signal has been done. An attempt to model the non-linearities from the Power Amplifier (PA), the imbalance from the IQ-mixer and the effects of the circulator has been done to as correctly as possible comply to the real signal distortions. Simulations using experimental data provided by Syntronic SRD was used to evaluate the cancellation for Recursive Least Square (RLS), Ordinary Least Square (OLS) and Normalized Least Mean Square (NLMS) algorithms. The simulations shows that a cancellation of over 45dB within the bandwidth can be achieved using digital cancellation in the baseband. The result shows the importance of having a weakly nonlinear transmit signal to achieve a better performance using FD. It was showed that the linear model shows significantly worse results incomparison to the Generalized Memory Polynomial (GMP) and Memory Polynomial (MP). The MP and GMP model achieve similar results in the weakly non-linear cases but the GMP outperforms the MP model in strongly non-linear cases.

5G är något som växer fram i samhällen över hela världen. Många stormakter så som USA och Ryssland satsar mycket pengar på att skapa användningsområden för 5G, inte minst i militära sammanhang. Sverige använder idag inte 5G i militära sammanhang. Totalförsvarets forskningsinstitut FOI har dock publicerat rapporter om tänkbara användningsområden för 5G i den militära verksamheten. Detta arbete tar det ett steg längre och ser till hur 5G kan nyttjas specifikt i stridslednings- och luftbevakningsbataljonen. Arbetet har en teknisk utgångspunkt och använder teorin militär nytta. Genom att presentera och analysera sju olika funktioner i 5G. Dessa är mjukvarudefinierande nät, multiantennsystem, self-interference cancellation, hantering av flera samtidiga användare, bredbandiga mottagare och millimetervåg, multikonnektivitet vid flera bärvågor och felrättande kodning. Slutsatsen är att 5G mycket väl kan nyttjas i stridslednings- och luftbevakningsbataljonen. Många av funktionerna passar väl in i bataljonens uppgifter och system. Dock skulle det krävas en omfattande ombyggnation av den befintliga arkitekturen av system som används idag för att 5G ska vara möjligt att implementera. Anledningen till detta är att stridslednings- och luftbevakningsbataljonens system är system av system och där ett system ej går att byta ut eller lägga till utan att andra system påverkas.

Le medium sans fil est une ressource partagée et limitée. Les normes sans fil actuelles partagent toujours le principe de partage du medium Half-Duplex: la transmission et la réception de signaux sont effectuées dans deux intervalles de temps distincts ou deux bandes de fréquences différentes. En outre, l'émetteur-récepteur ne peut émettre et recevoir qu’un signal à la fois. Cette thèse suit une autre approche: au lieu de partager le support avec le principe de Half-Duplex, toute la bande de fréquence autorisée est partagé pour la transmission et la réception simultanée, approche qui est appelée Full-Duplex. Dès lors, on peut concevoir une architecture d'un émetteur-récepteur radio flexible à large bande pour traiter deux types de signaux différents à la fois. Pour approcher cet objectif, nous utilisons une méthode de suppression active analogique de l’auto-interférence (AARFSIC) et l'annulation active numérique d'auto interférence dans le domaine temporel (ADSICT) pour annuler la forte auto-interférence (SI) induite par le principe Full-Duplex. Basé sur la radio Full-Duplex, nous proposons un système flexible Dual-Band (FDDB) émetteur-récepteur radio OFDM-Full Duplex en la combinant avec un front-end RF double bande. S'appuyant sur ces principes, nous exposons trois contributions principales: Nous présentons une technique d’annulation analogique de l’auto-interférence (ASIC), qui peut annuler complètement l’auto-interférence à trajet direct ou multi-trajets, basée sur la combinaison des méthodes AARFSIC et DSICT. Ensuite, nous présentons la conception et l'évaluation d'une radio OFDM Full-Duplex, y compris l'analyse et la qualification de l'impact du bruit thermique et du bruit de phase sur les performances du système. Enfin, nous développons une radio dual-bande FDDB OFDM qui peut fonctionner sur deux fragments de spectre séparés. Afin d'éliminer l'impact du déséquilibre I/Q sur la radio FDDB, une méthode d’estimation des déséquilibres I/Q et de compensation, simple mais efficace, est présentée. La simulation au niveau système menée avec ADS et Matlab montre que cette méthode peut effectivement compenser des déséquilibres I/Q aussi bien élevés que faibles. / The wireless medium is a shared and limited resource. Current wireless standards always share the medium with Half-Duplex principle: the transmission and reception of signals are done in two separate time slots or two different frequency bands. Besides, the transceiver can only transmit and receive one signal at a time. This dissertation takes an alternate approach: Instead of sharing the medium with Half-Duplex principle, the entire licensed frequency band is shared for simultaneous transmission and reception, which we call Full-Duplex. Besides, the design concept for a wideband flexible radio transceiver can process two different types of signals at a time. To approach this goal, we use an active analog radio frequency self-interference cancellation (AARFSIC) method or a combination scheme of the AARFSIC and active digital self interference cancellation in time domain (ADSICT) to cancel the strong self-interference (SI) induced by the Full-Duplex principle. Based on the Full-Duplex radio, we propose a flexible Full-Duplex Dual-Band (FDDB) OFDM radio transceiver by combining it with a Dual-Band RF front-end. Building on these, we make three main contributions: We present an active self-interference cancellation (ASIC) scheme, which can cancel both the strong one-path and multi-path SI completely, based on the combination of the AARFSIC and DSICT. Next, we introduce the design and evaluation of a Full-Duplex OFDM radio, including the analysis and qualification of the impact of the thermal noise and phase noise on the system performance. Finally, we develop a FDDB OFDM radio that can work on two separate spectrum fragments. In order to eliminate the impact of the I/Q imbalance on the FDDB radio, a simple but practical digital I/Q imbalance estimation and compensation method is presented. The system level simulation conducted with ADS and Matlab software shows that this method can effectively compensate both high and low I/Q imbalance.

With the tremendous growth in the mobile data traffic, the demand for highdata rate is increasing rapidly, and higher frequency resources shall be exploredto alleviate the congestion in the overcrowded spectrum, thus, the millimeterwave (mmWave) frequency resource ranging from 30 GHz to 300 GHz has beenrecognized as a nature fit for the fifth-generation (5G) and beyond network. Tocompensate the severe path-loss in the mmWave band as well to realize theefficient transmissions by applying the low-cost architecture, it is of intereststo investigate the beamforming schemes with large-scale antenna arrays andthe full-duplex (FD) relaying strategy, which are indispensable in the operationof directional signal transmission and the efficient spectrum utilization inthe mmWave transmission, respectively. However, the self-interference (SI)occurring between the separate antenna arrays is the main impediment inrealizing a FD wireless node while considering the simultaneous transmission andreception.This thesis project aims to design efficient hybrid beamforming algorithms toimprove spectral efficiency and eliminate SI. The orthogonal matching pursuit(OMP)-based hybrid analog-digital beamforming design, and the alternatingdirection method of multipliers (ADMM)-based schemes are explored to improvethe spectral efficiency and eliminate the SI in this work. Moreover, a fast ADMMenabledhybrid precoding approach with SI cancellation is proposed to achievethe efficient performance and superior convergence compared with the existingschemes, as it is verified by the presented numerical simulations. / Med den enorma tillväxten i den mobila datatrafiken ökar efterfrågan påhög datahastighet snabbt, och högre frekvensresurser ska undersökas för attminska trängseln i det överbefolkade spektrumet, vilket innebär att Volymvågens(mmwave) frekvensresurs, som sträcker sig från 30 GHz till 300 GHz, har erkäntssom en naturlig resurs för den femte generationen (5G) och utanför nätverket.För att kompensera den allvarliga förlusten av tågläge i mmwave-bandet ochför att förverkliga de effektiva sändningarna genom att tillämpa den billigaarkitekturen.Det är av intresse att undersöka strålformningsprogrammen medstorskaliga antennmatriser och strategin för återutläggning av hela duplex (FD),som är oumbärliga för att driva den direkta signal överföringen och det effektivaspektrumutnyttjandet i mmwave-transmissionen.separata antennmatriser är etthuvudhinder för att förverkliga en trådlös nod från FD samtidigt som manöverväger samtidig överföring och mottagning.Syftet med detta avhandlingsprojekt är att utforma effektiva kombineradestrålformningsinformationsalgoritmer för att förbättra spektraleffektiviteten ocheliminera SI. Den ortogonala matchande jakten (OMP)-baserad hybrid analogdigitalstrålformning, och metoden med alternerande riktning för multiplikatorer(ADMM)-baserade system utforskas för att förbättra spektraleffektiviteten ochelimineraSI i det här arbetet. Dessutom föreslås en snabb, adMM-aktiveradhybrid förkonditionering med SI-annullering för att uppnå effektiv prestandaoch överlägset konvergens jämfört med de befintliga systemen, eftersom denkontrolleras av de presenterade numeriska simuleringarna.

En raison de la demande croissante de services de communication sans fil et de la limitation des ressources de spectre, la radio cognitive (CR) a été initialement proposée pour résoudre la pénurie de spectre. CR divise les systèmes transmetteurs-récepteurs de communication en deux catégories : les Utilisateurs Principaux (PU) et les Utilisateurs Secondaires (SU). PU a le droit légal d'utiliser la bande spectrale, tandis que SU est un utilisateur opportuniste qui peut transmettre sur cette bande chaque fois qu'elle est vacante afin d'éviter toute interférence avec le signal de PU. De ce fait, la détection des activités de PU devient une priorité principale pour toute CR.Le Spectrum Sensing devient ainsi une partie importante d’un système CR, qui surveille les transmissions de PU. En effet, le Spectrum Sensing joue un rôle essentiel dans le mécanisme du fonctionnement du CR en localisant les canaux disponibles et, d'autre part, en protégeant les canaux occupés des interférences de la transmission SU. En fait, Spectrum Sensing a gagné beaucoup d'attention au cours de la dernière décennie, et de nombreux algorithmes sont proposés. Concernant la fiabilité de la performance, plusieurs défis comme le faible rapport signal sur bruit, l'incertitude de bruit (NU), la durée de détection du spectre, etc. Cette thèse aborde les défis de la détection du spectre et apporte quelques solutions. De nouveaux détecteurs basés sur la détection des caractéristiques cyclo-stationnaires et la densité spectrale de puissance (PSD) du signal de PU sont présentés. Un algorithme de test de signification de corrélation canonique (CCST) est proposé pour effectuer une détection cyclo-stationnaire. CCST peut détecter la présence des caractéristiques cycliques communes parmi les versions retardées du signal reçu. Ce test peut révéler la présence d'un signal cyclo-stationnaire dans le signal de mélange reçu. Une autre méthode de détection basée sur la PSD cumulative est proposée. En supposant que le bruit est blanc (sa PSD est plate), la PSD cumulative s'approche d'une droite. Cette forme devient non linéaire pour les signaux de télécommunication. Distinguer la forme cumulative PSD peut donc conduire à diagnostiquer l'état du canal.La radio cognitive Full-Duplex (FD-CR) a également été étudiée dans ce manuscrit, où plusieurs défis sont analysés en proposant de nouvelles contributions. Le fonctionnement FD permet au CR d'éviter la période de silence pendant la détection du spectre. Dans le système CR classique, le SU cesse de transmettre pendant la détection du spectre afin de ne pas affecter la fiabilité de détection. Dans FD-CR, SU peut éliminer la réflexion de son signal transmis et en même temps réaliser le Spectrum Sensing. En raison de certaines limitations, le résidu de l'auto-interférence ne peut pas être complètement annulé, alors la crédibilité de la détection du spectre est fortement affectée. Afin de réduire la puissance résiduelle, une nouvelle architecture de récepteur SU est élaborée pour atténuer les imperfections du circuit (comme le bruit de phase et la distorsion non linéaire de l'amplificateur à faible bruit du récepteur). La nouvelle architecture montre sa robustesse en assurant une détection fiable et en améliorant le débit de SU. / Due to the increasing demand of wireless communication services and the limitation in the spectrum resources, Cognitive Radio (CR) has been initially proposed in order to solve the spectrum scarcity. CR divides the communication transceiver into two categories: the Primary (PU) or the Secondary (SU) Users. PU has the legal right to use the spectrum bandwidth, while SU is an opportunistic user that can transmit on that bandwidth whenever it is vacant in order to avoid any interference to the signal of PU. Hence the detection of PU becomes a main priority for CR systems. The Spectrum Sensing is the part of the CR system, which monitors the PU activities. Spectrum Sensing plays an essential role in the mechanism of the CR functioning. It provides CR with the available channel in order to access them, and on the other hand, it protects occupied channels from the interference of the SU transmission. In fact, Spectrum Sensing has gained a lot of attention in the last decade, and numerous algorithms are proposed to perform it. Concerning the reliability of the performance, several challenges have been addressed, such as the low Signal to Noise Ratio (SNR), the Noise Uncertainty (NU), the Spectrum Sensing duration, etc. This dissertation addresses the Spectrum Sensing challenges and some solutions are proposed. New detectors based on Cyclo-Stationary Features detection and the Power Spectral Density (PSD) of the PU are presented. CanonicalCorrelation Significance Test (CCST) algorithm is proposed to perform cyclo-stationary detection. CCST can detect the presence of the common cyclic features among the delayed versions of the received signal. This test can reveal the presence of a cyclo-stationary signal in the received mixture signal. Another detection method based on the cumulative PSD is proposed. By assuming the whiteness of the noise (its PSD is at), the cumulative PSD approaches a straight line. This shape becomes non-linear when a telecommunication signal is present in the received mixture. Distinguishing the Cumulative PSD shape may lead to diagnose the channel status.Full-Duplex Cognitive Radio (FD-CR) has been also studied in this manuscript, where several challenges are analyzed by proposing a new contribution. FD functioning permits CR to avoid the silence period during the Spectrum Sensing. In classical CR system, SU stops transmitting during the Spectrum Sensing in order to do not affect the detection reliability. In FD-CR, SU can eliminate the reflection of its transmitted signal and at the same time achieving the Spectrum Sensing. Due to some limitations, the residual of the Self Interference cannot be completely cancelled, then the Spectrum Sensing credibility is highly affected. In order to reduce the residual power, a new SU receiver architecture is worked out to mitigate the hardware imperfections (such as the Phase Noise and the Non-Linear Distortion of the receiver Low-Noise Amplifier). The new architecture shows its robustness by ensuring a reliable detection and enhancing the throughput of SU.