Abstract This thesis is devoted to studying two wireless relay network models, namely wireless tandem multiple-input-multiple-output (MIMO) relay networks and wireless two-hop multicast relay networks. Regarding wireless tandem MIMO relay networks, we develop a systematic approach to analyze their fundamental diversity-multiplexing tradeoff (DMT) under the assumption that the relays implement a class of practical full-duplex techniques that enable them to opt for either full-duplex or half-duplex mode. Based on the analysis, we make contribution from the following aspects: First of all, we thoroughly compare the performance of full-duplex and half-duplex mode operations in the framework of wireless tandem relay networks. We find that both full-duplex and half-duplex modes have opportunity to outperform each other. Specifically, for many tandem relay networks, in the low multiplexing gain region, the best relay-mode configuration is to let all the relays operate in half-duplex mode since this relay-mode configuration achieves the best diversity gain in the low multiplexing gain region. However, in the high multiplexing gain region, the best diversity gain is usually achieved by switching some relays to full-duplex mode. Furthermore, we study how residual interference at relays working in full-duplex mode affects the DMT of a tandem network. We find that residual interference not only derogates the performance of full-duplex mode, but also affects the optimal power allocation of the network. Specifically, if residual interference is zero or has a sufficiently low power level, a linear power allocation scheme can achieve the optimal DMT of the network. Otherwise, the optimal DMT is achieved by a nonlinear power allocation scheme. Finally, the DMT analysis illustrates an effective principle to deal with general multi-hop wireless networks, which is to break them down into small scale subnetworks with certain key structures. Then, studying the general multi-hop wireless networks essentially becomes studying those small scale subnetworks and the relationship among them. Regarding wireless two-hop multicast relay networks, we focus on a case study where a single source multicasts to two destinations through the assistance of two relays. We propose and analyze the performance of a partial decode-and-forward protocol for the network, which includes the full decode-and-forward protocol as a special case and achieves a better performance in general. Specifically, we prove that the achievable rate of the partial decode-and-forward protocol can either reach arbitrarily close to the cut-set upper bound of the network or reach within 1 bit/s/Hz to that, asymptotically with respect to the transmit power. We also show that the partial decode-and-forward protocol can achieve the optimal DMT of the network. Then, we discuss the perspective of implementing the partial decode-and-forward strategy to more general multicast relay networks. / Tiivistelmä Tämä opinnäytetyö tutkii kahta langatonta välitysverkkomallia, nimittäin langatonta tandem multiple-input-multiple-output (MIMO) välitysverkkoa ja langatonta monilähetysvälitysverkkoa kahdelle hypylle. Kehitämme systemaattisen lähestymistavan diversiteetti-multipleksointi vaihtokaupan (DMT) analysointiin langattomiin tandem MIMO välitysverkkoihin, olettaen välittäjien käyttävän käytännöllisiä full-duplex lähetystekniikoita, jotka mahdollistavat valinnan joko full-duplex tai half-duplex lähetystilan välillä. Analyysin perusteella kontribuoimme seuraavilla tavoilla: Ensinnäkin, vertailemme perusteellisesti full-duplex sekä half-duplex lähetystiloja langattomissa tandem välitysverkoissa. Huomaamme, että molemmat full-duplex ja half-duplex lähetystilat voivat suoriutua toinen toistaan paremmin. Tarkemmin sanoen, monissa tandem välitysverkoissa silloin kun multipleksoinnin hyöty on alhainen, paras välitystapa on antaa kaikkien välittäjien käyttää half-duplex lähetystilaa, koska silloin saavutetaan paras diversiteettilisäys. Toisaalta, kun multipleksointilisäys on suuri, paras diversiteettilisäys saadaan yleensä asettamalla jotkin välittäjät full-duplex lähetystilaan. Lisäksi, tutkimme kuinka full-duplex lähetystilaa käyttävien välittäjien jäljelle jäävä interferenssi vaikuttaa tandemverkon DMT:aan. Huomaamme, että jäljelle jäävä interferenssi vähentää full-duplex mallin tehokkuutta ja lisäksi vaikuttaa optimaaliseen tehonjakamiseen verkossa. Tarkemmin sanoen, jos jäljelle jäävä interferenssin tehotaso on nolla tai tarpeeksi lähellä sitä, lineaarisella tehojaolla voi saavuttaa verkon optimaalisen DMT:n. Muutoin, optimaalinen DMT saavutetaan epälineaarisella tehojaolla. Lopuksi, DMT analyysi havainnollistaa tehokkaan periaatteen yleisluontoisten monihyppyverkkojen käsittelemiseen, eli verkon jakamisen pienempiin osiin erilaiin avainrakenteisiin. Tämän jälkeen yleisluntoisten langattoimen monihyppyverkkojen tutkiminen tapahtuu tutkimalla näitä pieniä osia ja niiden välisiä vuorovaikutussuhteita. Langattomaan kahden hypyn monilähetysvälitysverkkon osalta keskitymme tapaustutkimukseen, jossa yksi lähettäjä monilähettää kahdelle vastaanottajalle kahden välittäjän avulla. Ehdotamme tälle verkolle osittaista decode-and-forward protokollaa, joka sisältää täyden decode-and-forward protokollan erikoistapauksena ja saavuttaa yleisesti tätä protokollaa paremman tehokkuuden. Tarkemmin sanoen, todistamme että tällä protokollalla siirtonopeus lähetystehon suhteen joko lähenee asymptoottisesti verkon cut-set ylärajaa mielivaltaisen lähelle tai saavuttaa sen 1 bit/s/Hz sisään. Osoitamme myös, että osittainen decode-and-forward protokolla voi saavuttaa verkon optimaalisen DMT:n. Tämän jälkeen, käsittelemme osittaisen decode-and-forward strategian impelentointia yleisluontoisille monilähetysvälitysverkoille.

Finding an optimal solution to the problem of fast and efficient provisioning of reliable connections and failure recovery in future intelligent optical networks is an ongoing challenge. In this dissertation, we investigate and compare the performance of an adapted shared-path protection algorithm with a more conventional approach; both designed for survivable optical Wavelength Division Multiplexing (WDM) mesh networks. The effect of different classes of service on performance is also investigated. Dedicated path protection is a proactive scheme which reserves spare resources to combat single link failures. Conventional Shared-path Protection (CSP) is desirable due to the efficient utilization of resources which results from the sharing of backup paths. Availability is an important performance assessment factor which measures the probability that a connection is in an operational state at some point in time. It is the instantaneous counterpart of reliability. Therefore, connections that do not meet their availability requirements are considered to be unreliable. Reliability Aware Shared-path Protection (RASP) adopts the advantages of CSP by provisioning reliable connections efficiently, but provides protection for unreliable connections only. With the use of a link disjoint parameter, RASP also permits the routing of partial link disjoint backup paths. A simulation study, which evaluates four performance parameters, is undertaken using a South African mesh network. The parameters that are investigated are: 1. Blocking Probability (BP), which considers the percentage of connection requests that are blocked, 2. Backup Success Ratio (BSR), which considers the number of connections that are successfully provisioned with a backup protection path, 3. Backup Primary Resource Ratio (BPR), which considers the ratio of resources utilized to cater for working traffic to the resources reserved for protection paths and lastly 4. Reliability Satisfaction Ratio (RSR), which evaluates the ratio of provisioned connections that meet their availability requirements to the total number of provisioned connections. Under dynamic traffic conditions with varying network load, simulation results show that RASP can provision reliable connections and satisfy Service Level Agreement (SLA) requirements. A competitive Blocking Probability (BP) and lower Backup Primary Resource Ratio (BPR) signify an improvement in resource utilization efficiency. A higher Backup Success Ratio (BSR) was also achieved under high Quality of Service (QoS) constraints. The significance of different availability requirements is evaluated by creating three categories, high availability, medium availability and low availability. These three categories represent three classes of service, with availability used as the QoS parameter. Within each class, the performance of RASP and CSP is observed and analyzed, using the parameters described above. Results show that both the BP and BPR increase with an increase in the availability requirements. The RSR decreases as the reliability requirements increase and a variation in BSR is also indicated. / Dissertation (MEng)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted

First part of this thesis presents the design, validation, and implementation of an Orthogonal Frequency Division Multiplexing (OFDM) transmitter and receiver on a Cyclone II FPGA chip using DSP builder and Quartus II high level design tools. The resources in terms of logical elements (LE) including combinational functions and logic registers allocated by the model have been investigated and addressed. The result shows that implementing the basic OFDM transceiver allocates about 14% (equivalent to 6% at transmitter and 8% at receiver) of the available LE resources on an Altera Cyclone II EP2C35F672C6 FPGA chip, largely taken up by the FFT, IFFT and soft decision encoder. Secondly, a new wavelet-based OFDM system based on FDPP-DA based channel estimation is proposed as a reliable ECG Patient Monitoring System, a Personal Wireless telemedicine application. The system performance for different wavelet mothers has been investigated. The effects of AWGN and multipath Rayleigh fading channels have also been studied in the analysis. The performances of FDPP-DA and HDPP-DA-based channel estimations are compared based on both DFT-based OFDM and wavelet-based OFDM systems. The system model was studied using MATLAB software in which the average BER was addressed for randomized data. The main error differences that reflect the quality of the received ECG signals between the reconstructed and original ECG signals are established. Finally a DA-based architecture for 1-D iDWT/DWT based on an OFDM model is implemented for an ECG-PMS wireless telemedicine application. In the portable wireless body transmitter unit at the patient site, a fully Serial-DA-based scheme for iDWT is realized to support higher hardware utilization and lower power consumption; whereas a fully Parallel-DA-based scheme for DWT is applied at the base unit of the hospital site to support a higher throughput. It should be noted that the behavioural level of HDL models of the proposed system was developed and implemented to confirm its correctness in simulation. Then, after the simulation process the design models were synthesised and implemented for the target FPGA to confirm their validation.

Cognitive radios are the radios which use spectrum licensed to other users. For this, they perform Radio Environment Analysis, identify the Spectral holes and then operate in those holes. We consider the problem of Spectrum Sensing in Cognitive Radio Networks. Our Algorithms are based on Sequential Change Detection techniques. In this work we have used DualCUSUM, a distributed algorithm developed recently for cooperative spectrum sensing. This is used by cognitive (secondary) nodes to sense the spectrum which then send their local decisions to a fusion center. The fusion center again sequentially processes the received information to arrive at the final decision. We show that DualCUSUM performs better than all other existing spectrum sensing algorithms. We present a generalized analysis of DualCUSUM and compare the analysis with simulations to show its accuracy. DualCUSUM requires the knowledge of the channel gains for each of the secondary users and the receiver noise power. In Cognitive Radio setup it is not realistic to assume that each secondary user will have this knowledge. So later we modify DualCUSUM to develop GLRCUSUM algorithms which can work with imprecise estimates of the channel gains and receiver noise power. We show that the SNR wall problem encountered in this scenario by other detectors is not experienced by our algorithm. We also analyze the GLRCUSUM algorithms theoretically. We also apply our algorithms for detecting the presence of the primary in an Orthogonal Frequency Division Multiplexing (OFDM) setup. We first consider the Cyclic Prefix (CP) detector, which is considered to be robust to uncertainties in noise power, and further modify the CPdetector to take care of some of the common impairments like Timing offset, Frequency offset and IQ imbalance. We further modify the CPdetector to work under frequency selective channel. We also consider the energy detector under different impairments and show that the sequential detection based energy detectors outperform cyclic prefix based Detectors.

No description available.

Fault localization is the process of realizing the true source of a failure from a set of collected failure notifications. Isolating failure recovery within the network optical domain is necessary to resolve alarm storm problems. The introduction of the monitoring trail (m-trail) has been proven to deliver better performance by employing monitoring resources in a form of optical trails - a monitoring framework that generalizes all the previously reported counterparts. In this dissertation, the m-trail design is explored and a focus is given to the analysis on using m-trails with established lightpaths to achieve fault localization. This process saves network resources by reducing the number of the m-trails required for fault localization and therefore the number of wavelengths used in the network. A novel approach based on Geographic Midpoint Technique, an adapted version of the Chinese Postman’s Problem (CPP) solution and an adapted version of the Traveling Salesman’s Problem (TSP) solution algorithms is introduced. The desirable features of network architectures and the enabling of innovative technologies for delivering future millimeter-waveband (mm-WB) Radio-over-Fiber (RoF) systems for wireless services integrated in a Dense Wavelength Division Multiplexing (DWDM) is proposed in this dissertation. For the conceptual illustration, a DWDM RoF system with channel spacing of 12.5 GHz is considered. The mm-WB Radio Frequency (RF) signal is obtained at each Optical Network Unit (ONU) by simultaneously using optical heterodyning photo detection between two optical carriers. The generated RF modulated signal has a frequency of 12.5 GHz. This RoF system is easy, cost-effective, resistant to laser phase noise and also reduces maintenance needs, in principle. A revision of related RoF network proposals and experiments is also included. A number of models for Passive Optical Networks (PON)/ RoF-PON that combine both innovative and existing ideas along with a number of solutions for m-trail design problem of these models are proposed. The comparison between these models uses the expected survivability function which proved that these models are liable to be implemented in the new and existing PON/ RoF-PON systems. This dissertation is followed by recommendation of possible directions for future research in this area.

Depuis plusieurs années, les technologies de l’information et de la communication connaissent un développement spectaculaire. Le trafic d’information augmente exponentiellement alors que l’évolution de l’efficacité énergétique des réseaux, définie généralement comme le rapport entre l’énergie utile en sortie du système et l’énergie totale fournie au système, n’augmente que de manière linéaire. Pour soutenir la demande de trafic, il est alors nécessaire de multiplier les équipements réseaux ce qui augment la facture énergétique des opérateurs et les émissions de gaz carbonique. Devant l’urgence de la situation, de nombreux projets et consortiums ont été créés avec l’objectif de renforcer l’efficacité énergétique des réseaux. Par exemple, le consortium GreenTouch™ fondé en 2010 a pour objectif d’améliorer l’efficacité énergétique des réseaux d’un facteur 1000 d’ici 2015 et de réduire leur consommation énergétique de 90% d’ici 2020 (par rapport à 2010). Le projet METIS a pour objectif de définir les télécommunications de 2020 (5G) cherche des solutions efficaces minimisant les coûts, les ressources et la consommation énergétique. Le projet MiWEBA qui intègre les ondes millimétrique aux communications mobiles dans le but d’augmenter la capacité du réseau d’un facteur 1000 avec un coût raisonnable.Dans cette thèse, nous abordons deux solutions répondant aux challenges de la 5G et permettant de réduire les niveaux des puissances rayonnées par les systèmes de télécommunications : l’amélioration de la couche physique via les techniques de focalisation spatiale et l’adaptation de lien multi-technologies. L’objectif principal de la thèse est de réaliser des transmissions de données très haut débit à forte efficacité énergétique à l’aide d’une connectivité multi-technologies sans coutures y compris dans des réseaux comprenant une multitude de périphériques à faible complexité.L’organisation de la thèse est la suivante : tout d’abord, l’implémentation de techniques de focalisation spatiale, le Retournement Temporel (RT) et l’EGT (Equal Gain Transmission), dans un système utilisant les dernières évolutions du standard IEEE 802.11, notamment l’intégration d’une composante 60 GHz, est étudiée. Les performances de ces techniques sont analysées de manière à identifier les conditions optimales de leur utilisation et il est montré qu’avec un minimum de deux antennes de transmission, elles permettent d’améliorer les performances énergétiques des systèmes tout en ayant une faible complexité d’implémentation. Des modifications du standard permettant d’augmenter l’efficacité énergétique sont également proposées. Une analyse cross-layer est ensuite réalisée afin de définir protocoles d’estimation de canal tenant compte des spécificités du RT. De plus, les améliorations énergétiques liées à l’utilisation du RT sont confirmées en tenant compte des dégradations des performances de la couche de liaison. Enfin, une métrique d’occupation temporelle est définie et associée à des techniques d’adaptation de lien mono et multi-technologies existantes dans le but d’améliorer la sélection d‘interfaces de transmission pour augmenter l’efficacité énergétique sans affecter les performances des systèmes utilisant un accès aléatoire au canal de communication. L’utilisation de cette métrique permet, dans certaines configurations, d’augmenter d’un facteur sept l’efficacité énergétique d’un système utilisant le Wi-Fi et, dans le cas multi-technologies, de répartir le trafic sur les différentes interfaces de transmission afin d’éviter la saturation des canaux de communication. / Over the past few years, information and communications technologies have experienced a spectacular development. Traffic demand grows exponentially while energy efficiency of networks –usually defined as the ratio between delivered power and supplied power- only increases linearly. In order to supply the data traffic, it is necessary to duplicate networks equipments increasing energy costs for operators and carbon dioxide emissions. To face this dramatic situation, several projects and consortiums have been created and aim to increase networks energy efficiency. For instance, the GreenTouch™ consortium funded in 2010 aims to improve networks energy efficiency by a factor 1000 by 2015 and to reduce energy consumption of TICs by 90% by 2020 (compared with 2010 levels). METIS project aims to define 2020s communications (5G) search for efficient solutions with low costs, low resources use and low power consumption of systems. MiWEBA project brings millimeter-waves into the mobile radio word to extend the network capacity by 1000 at reasonable cost.In this thesis we study two solutions to answer 5G challenges and reduce radiated power levels of telecommunications systems: physical layer improvements through spatial focalization techniques and multi-technologies link adaptation. This thesis main goal is to achieve very high data transmission rates with high energy efficiency and seamless connectivity using multiple-interfaces technologies even in networks composed of a high number of low-complexity devices.The thesis is organized as follows: first, Time Reversal (TR) and Equal Gain Transmission (EGT) implementation is studied and applied to a system using the latest amendments of IEEE 802.11 standard, including 60 GHz transmissions. Performance of these techniques is analyzed in order to identify optimal conditions of use and it is shown that they only require a minimum of two transmit antennas to increase the energetic performance of systems while having a low implementation complexity. Standard modifications allowing an increase of energy efficiency are proposed. Then, a cross-layer analysis is performed to define channel estimation protocols taking TR specificities into account. Moreover, TR energetic benefits are validated considering its drawbacks at the link layer level. Finally, a time-availability metric is defined and associated to existing mono or multi-technologies adaptation techniques and aim to increase energy efficiency without degrading the performance of systems using random access to the communication channel. This metrics allows –in some configurations- to increase by a factor seven the energy efficiency of a system using Wi-Fi and, in a multi-technologies scenario, to allocate the data traffic to the several interfaces in order to avoid communication channels saturation.

Orientador : Yuzo Iano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-18T12:22:10Z (GMT). No. of bitstreams: 1 Akamine_Cristiano_D.pdf: 23517707 bytes, checksum: c51b616b01118b57a56b6af1f6bec625 (MD5) Previous issue date: 2011 / Resumo: Este trabalho apresenta contribuições para o sistema brasileiro de TV digital. Considera-se a incompatibilidade do BTS (Broadcast Transport Stream) com os sistemas de distribuição de TV digital existentes e a dificuldade de implementação do modulador e demodulador ISDB-TB. Em primeiro lugar um algoritmo inovador capaz de realizar a compressão e adaptação do BTS tomando-o compatível com a maioria dos equipamentos comerciais do sistema DVB, é proposto. Em seguida, um detalhamento do funcionamento do modulador e demodulador é realizado utilizando-se expressões matemáticas e resultados obtidos em simulações computacionais. A partir do BTS, foi desenvolvido um simulador do modulador capaz de monitorar a entrada e saída de todos os blocos de processamento. No último estágio, vetores de RF são criados e podem ser utilizados em simulações computacionais e geradores de forma de onda arbitrária. Utilizando vetores de RF de emissoras de TV, foi desenvolvido um simulador do demodulador ISDB-TB. Esse simulador realiza as operações de sincronismo, estimação de canal, demodulação e decodificação de canal. Além disso, monitores da relação sinal ruído, constelação, resposta em frequência, perfil de atraso e taxa de erro de bits são utilizados para monitorar a reconstrução do BTS / Abstract: This paper presents contributions to the Brazilian digital TV system. It considers the incompatibility of (BTS) Broadcast Transport Stream with the existing digital TV distribution systems. The difficulty of implementation of the ISDB-TB modulator and demodulator are also taken into account. Firstly, an innovative algorithm able to compress and adapt the BTS in order to make it compatible with most DVB commercial equipment is implemented. Then, the detailed operation of the modulator and emodulator are obtained sing mathematical expressions and results from computer simulations. Using the BTS, it has been developed a simulator capable of monitoring the modulation input and output of all processing blocks. In the last stage, the RF vectors are created and can be used on computer simulations and arbitrary waveform generators. Using RF vectors of TV stations, an ISDB-Ts demodulator simulator was developed. This simulator performs the operations of synchronization, channel estimation, demodulation and channel decoding. In addition, monitors of signal to noise ratio, constellation, frequency response, delay profile and bit error rate are used to monitor the reconstruction of the BTS / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

[pt] A análise da técnica de demodulação usada para interrogar sensores a rede de Bragg em fibras ópticas baseadas em filtros fixos foi realizada teoricamente e experimentalmente. Diferentes configurações de sistemas foram analisadas modificando a posição espectral dos filtros, assim como os níveis de potência óptica obtidos nos fotodetectores. Foram realizadas medidas com o tempo de integração que variavam de 0.01 a 1s e estimado o limite de baixa freqüência. Comparação entre os resultados experimentais e simulados mostram boa concordância, e extrapolações indicam que seria possível chegar a uma faixa de medida da ordem de 7 nanômetros, com incertezas equivalentes menores que 2 picometros, na medida da posição de pico do sensor. Foi feita uma análise da possibilidade de utilização desta técnica para medida simultânea de pressão e temperatura com uma única rede sensora. Na realização experimental foi usado um transdutor de pressão que transferia uma força transversal à fibra, proporcional à pressão atuante, gerando birrefringência na região da rede de Bragg. Foi possível obter valores de pressão com a faixa dinâmica de 400 psi com incerteza máxima de 4 psi e simultaneamente temperaturas com variação de 28 a 50 graus Celsius com incerteza máxima de 0.1 graus Celsius. Adicionalmente, foram estudados os efeitos gerados em uma multiplexação temporal (TDM) de sensores a rede de Bragg quando os sensores se encontram superpostos na mesma posição espectral. Nesta análise é confrontada a técnica de demodulação utilizando dois filtros fixos com a técnica baseada na posição espectral. Os resultados indicam que a técnica baseada em filtros fixos apresenta vantagem, permitindo um número significativamente maior de sensores. E também, foi analisado o distúrbio provocado no espectro da rede sensora quando a fonte de luz usada para interrogar a rede tem uma modulação espectral que varia com a temperatura. Finalmente, foi apresentado um sistema de multiplexação (TDM/WDM), completamente polarizado, capaz de interrogar dezenas de sensores a rede de Bragg escrito em fibras de alta birrefringência. O sistema de multiplexação consistiu em uma chave óptica integrada, baseada em um interferômetro de Mach-Zehnder com configuração X-Y, e em um espectrômetro com um CCD linear como elemento de detecção. / [en] The analysis of a demodulation system for fiber Bragg grating sensors based on two fixed spectral filters has been carried out both theoretically and experimentally. Different system configurations were analyzed by modifying the spectral position of the filters as well as the optical power-level of the signal reaching the two photo-detectors. Measurements with integration times that varied from 0.01 to 1 second have been compared with the low frequency limit predicted for long-term operation. Comparisons between simulated and experimental results show good agreement, and extrapolations indicate that it should be possible to achieve a dynamic range of the order of 7 nanometers, with uncertainties equivalent to less than 2 picometers, in measurements of the sensor peak position. Applications based on this system were carried out. An analysis of simultaneous measurement of temperature and pressure with only one FBG sensor using transducer of pressure to transfer a lateral force to the fiber, proportional to the applied pressure, generating birefringence at grating Bragg region has been realized. The proposed system allowed to measure pressure range of 400 psi with uncertain of 4 psi and simultaneously temperature range of 22 Celsius Degree with uncertain of 0.1 Celsius Degree. In addiction, generated effects in the temporal multiplexing (TDM) of fiber Bragg grating sensors when the sensor spectra are fully overlapped have been analyzed. In this study, it is compared the demodulation technique based on two fixed filters with the conventional technique based on the peak position. The results show that the technique based on fixed filters presents advantage to conventional, allowing a greatest sensor number. It was also analyzed the generated disturbance in the Bragg grating sensor spectrum when the source used to interrogate the sensor has a residual modulation which changes with the temperature. And finally, a polarized multiplexing system (TDM/WDM) able to interrogate a large number of Bragg grating sensors written in high-birefringent polarization-maintaining fibers has been realized. It is based on integrated-optic switch Mach- Zehnder interferometer in X-Y configuration and a CCD line array spectrometer.

<div>With the constant advancement of modern radio technology, the safety of radio communication has become a growing concern for us. Communication has become an essential component, particularly in the application of modern technology such as unmanned aerial vehicle (UAV). As a result, it is critical to ensure that a drone can fly safely and reliably while completing duties. Simultaneously, machine learning (ML) is rapidly developing in the twenty-first century. For example, ML is currently being used in social media and digital marking for predicting and addressing users' varies interests. This also serves as the impetus for this thesis. The goal of this thesis is to combine ML and radio communication to identify and classify UAV interference with high accuracy.</div><div>In this work, a ML approach is explored for detecting and classifying jamming attacks against orthogonal frequency division multiplexing (OFDM) receivers, with applicability to UAVs. Four types of jamming attacks, including barrage, protocol-aware, single-tone, and successive-pulse jamming, are launched and analyzed using software-defined radio (SDR). The jamming range, launch complexity, and attack severity are all considered qualitatively when evaluating each type. Then, a systematic testing procedure is established, where a SDR is placed in the vicinity of a drone to extract radiometric features before and after a jamming attack is launched. Traditional ML methods are used to create classification models with numerical features such as signal-to-noise ratio (SNR), energy threshold, and important OFDM parameters. Furthermore, deep learning method (i.e., convolutional neural networks) are used to develop classification models trained with spectrogram images filling in it. Quantitative indicators such as detection and false alarm rates are used to evaluate the performance of both methods. The spectrogram-based model correctly classifies jamming with a precision of 99.79% and a false-alarm rate of 0.03%, compared to 92.20% and 1.35% for the feature-based counterpart.</div>