The multi-conductor lossy transmission-line model and finite element simulation tool are used to analyze the high-frequency attenuator and the DM transmission-line EMI filter. The insertion gain, transfer gain, current distribution, and input impedance of the filter under a nominal design are discussed. In order to apply the transmission-line EMI filter to power electronics systems, the performance of the filter under different dimensions, material properties, and source and load impedances must be known. The influences of twelve parameters of the DM transmission-line EMI filter on the cut-off frequency, the roll-off slope, and other characteristics of the insertion gain and transfer gain curves are investigated. The most influential parameters are identified. The current sharing between the copper and nickel conductors under different parameters are investigated. The performance of the transmission-line EMI filter under different source and load impedances is also explored. The measurement setups of the DM transmission-line EMI filter using a network analyzer have been discussed. The network analyzer has a common-ground problem that influences the measured results of the high-frequency attenuator. However, the common-ground problem has a negligible influence on the measured results of the DM transmission-line EMI filter. The connectors and copper strips between the connectors and the filter introduce parasitic inductance to the measurement setup. Both simulated and measured results show that transfer gain curve is very sensitive to the parasitic inductance. However, the insertion gain curve is not sensitive to the parasitic inductance. There are two major methods to reduce the parasitic inductance of the measurement setup: using small connectors and applying a four-terminal measurement setup. The transfer gain curves of three measurement setups are compared: the two-terminal measurement setup with BNC connectors, the two-terminal measurement setup with Sub Miniature version B (SMB) connectors, and the four-terminal measurement setup with SMB connectors. The four-terminal measurement setup with SMB connectors is the most accurate one and is applied for all the transfer gain measurements in this dissertation. This dissertation also focuses on exploring ways to improve the performance of the DM transmission-line EMI filter. Several improved structures of the DM transmission-line EMI filter are investigated. The filter structure without insulation layer can greatly reduce the thickness of the filter without changing its performance. The meander structure can increase the total length of the filter without taking up too much space and results in the cut-off frequency being shifted lower and achieving more attenuation. A prototype of the two-dielectric-layer filter structure is built and measured. The measurement result confirms that a multi-dielectric-layer structure is an effective way to achieve a lower cut-off frequency and more attenuation. This dissertation proposes a broadband DM EMI filter combining the advantages of the discrete reflective LC EMI filter and the transmission-line EMI filter. Two DM absorptive transmission-line EMI filters take the place of the two DM capacitors in the discrete reflective LC EMI filter. The measured insertion gain of the prototype has a large roll-off slope at low frequencies and large attenuation at high frequencies. The dependence of the broadband DM EMI filter on source and load impedances is also investigated. Larger load (source) impedance gives more attenuation no matter it is resistive, inductive or capacitive. The broadband DM EMI filter always has more high-frequency attenuation than the discrete reflective LC EMI filter under different load (source) impedances. / Ph. D.

This dissertation first studies two-dimensional wavelet codes (TDWCs). TDWCs are introduced as a solution to the problem of designing a 2-D code that has low decoding- complexity and has the maximum erasure-correcting property for rectangular burst erasures. The half-rate TDWCs of dimensions N₁ X N₂ satisfy the Reiger bound with equality for burst erasures of dimensions N₁ X N₂/2 and N₁/2 X N₂, where GCD(N₁,N₂) = 2. Examples of TDWC are provided that recover any rectangular burst erasure of area N₁N₂/2. These lattice-cyclic codes can recover burst erasures with a simple and efficient ML decoding. This work then studies the problem of distributed source coding for two and three correlated signals using channel codes. We propose to model the distributed source coding problem with a set of parallel channel that simplifies the distributed source coding to de- signing non-uniform channel codes. This design criterion improves the performance of the source coding considerably. LDPC codes are used for lossless and lossy distributed source coding, when the correlation parameter is known or unknown at the time of code design. We show that distributed source coding at the corner point using LDPC codes is simplified to non-uniform LDPC code and semi-random punctured LDPC codes for a system of two and three correlated sources, respectively. We also investigate distributed source coding at any arbitrary rate on the Slepian-Wolf rate region. This problem is simplified to designing a rate-compatible LDPC code that has unequal error protection property. This dissertation finally studies the distributed source coding problem for applications whose wireless channel is an erasure channel with unknown erasure probability. For these application, rateless codes are better candidates than LDPC codes. Non-uniform rateless codes and improved decoding algorithm are proposed for this purpose. We introduce a reliable, rate-optimal, and energy-efficient multicast algorithm that uses distributed source coding and rateless coding. The proposed multicast algorithm performs very close to network coding, while it has lower complexity and higher adaptability.

Honeywell Technology Solutions Lab, India / Weather is a major contributing factor in aviation accidents, incidents and delays. Doppler weather radar has emerged as a potent tool to observe weather. Aircraft carry onboard radars but their range and angular resolution are limited. Networks of ground-based weather radars provide extensive coverage of weather over large geographic regions. It would be helpful if these data can be transmitted to the pilot. However, these data are highly voluminous and the bandwidth of the ground-air communication links is limited and expensive. Hence, these data have to be compressed to an extent where they are suitable for transmission over low-bandwidth links. Several methods have been developed to compress pictorial data. General-purpose schemes do not take into account the nature of data and hence do not yield high compression ratios. A scheme for extreme compression of weather radar data is developed in this thesis that does not significantly degrade the meteorological information contained in these data. The method is based on contour encoding. It approximates a contour by a set of systematically chosen ‘control points’ that preserve its fine structure up to a certain level. The contours may be obtained using a thresholding process based on NWS or custom reflectivity levels. This process may result in region and hole contours, enclosing `high' or `low' areas, which may be nested. A tag bit is used to label region and hole contours. The control point extraction method first obtains a smoothed reference contour by averaging the original contour. Then the points on the original contour with maximum deviation from the smoothed contour between the crossings of these contours are identified and are designated as control points. Additional control points are added midway between the control point and the crossing points on either side of it, if the length of the segment between the crossing points exceeds a certain length. The control points, referenced with respect to the top-left corner of each contour for compact quantification, are transmitted to the receiving end. The contour is retrieved from the control points at the receiving end using spline interpolation. The region and hole contours are identified using the tag bit. The pixels between the region and hole contours at a given threshold level are filled using the color corresponding to it. This method is repeated till all the contours for a given threshold level are exhausted, and the process is carried out for all other thresholds, thereby resulting in a composite picture of the reconstructed field. Extensive studies have been conducted by using metrics such as compression ratio, fidelity of reconstruction and visual perception. In particular the effect of the smoothing factor, the choice of the degree of spline interpolation and the choice of thresholds are studied. It has been shown that a smoothing percentage of about 10% is optimal for most data. A degree 2 of spline interpolation is found to be best suited for smooth contour reconstruction. Augmenting NWS thresholds has resulted in improved visual perception, but at the expense of a decrease in the compression ratio. Two enhancements to the basic method that include adjustments to the control points to achieve better reconstruction and bit manipulations on the control points to obtain higher compression are proposed. The spline interpolation inherently tends to move the reconstructed contour away from the control points. This has been somewhat compensated by stretching the control points away from the smoothed reference contour. The amount and direction of stretch are optimized with respect to actual data fields to yield better reconstruction. In the bit manipulation study, the effects of discarding the least significant bits of the control point addresses are analyzed in detail. Simple bit truncation introduces a bias in the contour description and reconstruction, which is removed to a great extent by employing a bias compensation mechanism. The results obtained are compared with other methods devised for encoding weather radar contours.

Abstract In the current LTE-Advanced system, decode-and-forward (DF) is leveraged for cooperative relaying, where the erroneously decoded sequences are discarded at the relay, resulting in a waste of resources. The reason lies in that the erroneously decoded sequence can provide a certain amount of useful information about the source at the destination. Therefore, we develop a new relaying scheme, called lossy DF (also known as lossy forward (LF)), where the relay always forwards the decoded sequence to the destination. Beneficial from the always-forward principle, it has been verified that LF relaying outperforms DF relaying in terms of outage probability, ε-outage achievable rate, frame error rate (FER), and communication coverage. Three exemplifying network scenarios are studied in this thesis: the one-way multiple-input multiple-output (MIMO) relay network, the multiple access relay channel (MARC), and the general multi-source multi-relay network. We derive the outage probability of the one-way MIMO relay networks under the assumption that the orthogonal space-time block code (OSTBC) is implemented at the transmitter side for each individual transmission. Interestingly, we find that the diversity order of the OSTBC based one-way MIMO relay network can be interpreted and formulated by the well-known max-flow min-cut theorem, which is widely utilized to calculate the network capacity. For the MARC, non-orthogonal transmission is introduced to further improve the network throughput compared to its orthogonal counterpart. The region for lossless recovery of both sources is formulated by the theorem of multiple access channel (MAC) with a helper, which combines the Slepian-Wolf rate region and the MAC capacity region. Since the region for lossless recovery is obtained via sufficient condition, the derived outage probability can be regarded as a theoretical upper bound. We also conduct the performance evaluation by exploiting different accumulator (ACC) aided turbo codes at the transmitter side, exclusive or (XOR) based multi-user complete decoding at the relay, and iterative joint decoding (JD) at the destination. For the general multi-source multi-relay network, we focus on the investigation the end-to-end outage probability. The performance improvement of LF over DF is verified through theoretical analyses and numerical results in terms of outage probability. / Tiivistelmä Tämän päivän LTE-A-tiedonsiirtojärjestelmissä hyödynnetään dekoodaa-ja-välitä (decode-and-forward, DF) menetelmää yhteistoiminnalliseen tiedon edelleenlähetykseen (relaying) siten, että virheellisesti vastaanotetut sekvenssit hylätään välittimessä (relay). Tämä on resurssien hukkaamista, sillä virheellisissäkin viesteissä on informaatiota, jota voidaan hyödyntää vastaanottimessa. Tässä väitöskirjassa tutkitaan uutta häviöllistä DF-menetelmää, johon viitataan nimellä häviöllinen välitys (lossy forward, LF). Menetelmässä välitin lähettää informaation aina eteenpäin olipa siinä virheitä tai ei. Sen etuna verrattuna perinteiseen DF-menetelmään, on parantunut luotettavuus metriikoilla jossa mitataan vastaanoton todennäköisyyttä ja verkon peittoaluetta. Väitöskirjassa tarkastellaan LF-menetelmää kolmessa eri verkkotopologiassa jotka ovat yksisuuntainen monitulo-monilähtövälitinverkko (multiple-input multiple-output, MIMO), moniliityntävälitinkanava (multiple access relay channel, MARC), sekä yleinen moniläheinen monivälitinverkko. Työssä johdetaan matemaattinen esitys estotilan todennäköisyydelle (outage probability) yksisuuntaisessa MIMO-välitinverkossa olettaen ortogonaalisen tila-aika lohkokoodin (orthogonal space-time block code, OSTBC) käyttö. Estotilan todennäköisyys esitetään käyttäen toisteastta (diversity order), joka saadaan johdettua tunnetusta max-flow min-cut lauseesta, jota puolestaan käytetään yleisesti erilaisten verkkojen kapasiteettien laskentaan. MARC-topologiassa hyödynnetään ei-ortogonaalista lähetystä verkon datavirran kasvattamiseen. Häviöttömän lähetyksen informaatioteoreettinen kapasiteettialue saadaan johdettua MAC-auttajan kanssa. Lähestymistavassa Slepian-Wolf- sekä MAC-kapasiteettialueet yhdistyvät. Alueelle, jossa kahden lähteen lähetysnopeudet ovat sellaiset, että vastaanotto on häviötöntä, annetaan riittävä ehto, jolloin johdettu estotilan todennäköisyys on teoreettinen yläraja. Suorituskykyä evaluoidaan myös tietokonesimulaatioilla, joissa käytetään erilaisia akkumulaattoriavusteisia turbokoodeja lähettimessä, ehdoton tai (exclusive or, XOR) pohjaista monen käyttäjän dekoodausta välittimessä sekä iteratiivista yhteisdekoodausta vastaanottimessa. Yleisessä monilähteisessä monivälitinverkossa keskitytään alkuperäisen lähetyksen estotilatodennäköisyyteen. Teoreettinen analyysi sekä simulaatiot osoittavat, että LF:n estotilan todennäköisyys on pienempi kuin DF:n.

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Les études présentées dans cette thèse font l’objet d’un travail innovant concernant la conception des antennes pour les réseaux de type BAN et la modélisation des canaux associés. L’ouvrage de thèse est réparti en quatre chapitres. Deux chapitres sont consacrés à la modélisation de la propagation le long du corps où l’on montre que les formulations analytiques d’ondes de surface et d’ondes rampantes sont applicables dans ce contexte. L’effet des tissus adipeux est également pris en compte par le biais d’un modèle à trois couches (peau, graisse et muscle) et renseigne sur la variabilité du bilan de liaison suivant les personnes. Ce type de modélisation est le premier à inclure les formes du corps, les caractéristiques électriques des tissus biologiques et les caractéristiques de rayonnement des antennes. Une méthode basée sur l’autocorrélation du canal est également présentée afin de connaître les temps de cohérences des évanouissements lents et rapides. Par la suite, il est montré comment les évanouissements lents sont extraits par le biais d’un filtrage FFT fonction du temps de cohérence associé. L’étude des canaux se termine sur une série de mesures en chambre anéchoïde qui a permis de vérifier la validité des modèles analytiques. Des mesures en milieu indoor ont abouti à la proposition de plusieurs modèles statistiques basés sur une loi de Nakagami-m fonction de la distance sur le corps. Deux autres chapitres sont consacrés à la conception d’antennes à proximité de tissus biologiques et devant être intégrées dans des biocapteurs ou des vêtements. Pour cela, nous nous sommes particulièrement intéressés aux structures en F-inversé comme les IFA imprimées et les PIFA. Nous avons également réalisé des monopôles courts ayant un comportement de type magnétique. Nous montrons par le biais de simulations et de mesures sur un fantôme que seules les antennes du type monopôle et PIFA permettent une bonne excitation des ondes de surface. On montre par la suite l’influence du facteur de qualité d’une antenne sur son rendement et l’on en conclue qu’une antenne doit présenter un facteur de qualité faible pour avoir un bon rendement. La désensibilisation d’une antenne face au corps est également présentée. L’emploi de feuilles de ferrites aide à concentrer le champ réactif et limite ainsi les inévitables désadaptations dues au corps. Le coefficient de qualité joue également un rôle important dans le comportement de l’antenne face aux variabilités des tissus biologiques. L’estimation du rendement est un autre point difficile à réaliser lorsque les antennes sont sur le corps. Malgré tout nous proposons une nouvelle méthode que nous vérifions par simulation. Finalement, une structure à diversité est également proposée. Cette dernière tient compte des connaissances acquises au long de ce travail de recherche. Une sélection des meilleurs types d’antennes du point de vu canal et rendement est réalisée. La structure choisie est composée d’une PIFA et d’un monopôle court découplés par le biais de fentes λ/4. Des mesures in situ en milieu indoor donnent un gain en diversité maximum de 8.1 dB pour un schéma de type sélection / BAN antennas conception and channel modelling

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Frequent-pattern mining from databases has been widely studied and frequently observed. Unfortunately, these algorithms are not suitable for data stream processing. In frequent-pattern mining from data streams, it is important to manage sets of items and also their history. There are several reasons for this; it is not just the history of frequent items, but also the history of potentially frequent sets that can become frequent later. This requires more memory and computational power. This thesis describes two algorithms: Lossy Counting and FP-stream. An effective implementation of these algorithms in C# is an integral part of this thesis. In addition, the two algorithms have been compared.

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Multi-standard RF front-end is a critical part of legacy and future emerging mobile architectures, where the size, the efficiency, and the integration of the elements in the RF front-end will affect the network key performance indicators (KPIs). This chapter discusses power amplifier design for both handset and base station applications for 5G and beyond. Also, this chapter deals with filter-antenna design for 5G applications that include a synthesis-based approach, differentially driven reconfigurable planar filter-antenna, and an insensitive phased array antenna with air-filled slot-loop resonators.