Η διερεύνηση της περιοχής χωρητικότητας και της περιοχής επιτεύξιμων ρυθμών μετάδοσης καναλιών αποτελεί βασικό αντικείμενο της Θεωρίας Πληροφορίας. Η Ευθυγράμμιση Παρεμβολών είναι μια καινούρια ιδέα που δίνει μια εναλλακτική οπτική στο αντικείμενο αυτό, μέσω της διαφορετικής λογικής που εισάγει σχετικά με την κωδικοποίηση και τη μετάδοση της πληροφορίας. Σε πρόσφατες δημοσιεύσεις έχουν προταθεί μοντέλα που επιτρέπουν την εφαρμογή της θεωρίας της Ευθυγράμμισης Παρεμβολών και τη χρήση της σε πρακτικά συστήματα επικοινωνιών και καταδεικνύουν την υπεροχή της σε σχέση με συμβατικές μεθόδους. Παράλληλα, παρόλο που προς το παρόν έχει δοθεί έμφαση στην εδραίωση της Ευθυγράμμισης Παρεμβολών στις επικοινωνίες, η μαθηματική της βάση καθιστά δυνατή την εφαρμογή της σε αντικείμενα που ανήκουν σε άλλους τομείς. Σκοπός της παρούσας εργασίας είναι η μελέτη και η εφαρμογή της Αναδρομικής Ευθυγράμμισης Παρεμβολών για μετάδοση πληροφορίας σε Συστήματα Επικοινωνιών, καθώς και η διερεύνηση της απόδοσης της μεθόδου σε πρακτικά συστήματα. / The study of the channel capacity region and the achievable rate region is one of the main topics of Information Theory. Interference Alignment is a new idea that provides new insights through the introduction of a different viewpoint on data encoding and transmission. In recent publications, models have been proposed that allow the application of the theory of Interference Alignment to practical communication systems and demonstrate its superiority compared to traditional approaches. Furthermore, although for the time being emphasis has been put on establishing the use of Interference Alignment to communication systems, its mathematical formulation makes possible its use to other areas. The purpose of this thesis is to study and to apply Retrospective Interference Alignment to data transmission in communication systems and to evaluate the performance of the method in practical systems.

<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.

This diploma thesis is dealing with the basic knowledge of the Electromagnetic compatibility. It’s concretely target on electromagnetic interference flowing from the application of electronic gas control by Honeywell company. Author compile the power control board with including software in language C. The next alternates of power control board with the separated microprocessor were designed for the more extended source detection. On these boards there were explored shielding surface features placed directly under the microprocessor. The application reducing the interference was designed in accordance to the rules finding out during this diploma thesis writing.

This dissertation focuses on quantifying the effects of multi-user co-channel interference for an avionic communication system operating in a heavy-traffic aeronautical mobile environment and proposes advanced interference cancellation techniques to mitigate the interference. The dissertation consists of two parts. The first part of the work investigates the use of a visualization method to quantify and characterize the multi-user co-channel interference (multiple access interference) effects impinging on an avionic communication system. The interference is caused by complex interactions of thousands of RF signals transmitted from thousands of aircraft; each attempts to access a common communication channel, which is governed by a specific channel contention access protocol. The visualization method transforms the co-channel interference, which is specified in terms of signal-overlaps (signal collisions), from a visual representation to a matrix representation for further statistical analysis. It is found that the statistical Poisson and its cumulative distribution provide the best estimates of multi-user co-channel interference. It is shown, using Monte Carlo simulation, that the co-channel interference of a victim aircraft operating in the heavy-traffic environment could result in as high as eight signal-overlaps. This constitutes to approximately 83.4% of success rate in signal detection for the entire three thousand aircraft environment using conventional FSK receiver. One key finding shows that high-quality communications, up to 98.5% success rate, is achievable if only three overlapping signals can be decoded successfully. The interference results found in the first part set the stage for interference cancellation research in the second part. The second part of the work proposes the use of advanced interference cancellation techniques, namely sequential interference cancellation (SIC) and parallel interference cancellation (PIC), as potential solutions to mitigating the interference effects. These techniques can be implemented in radio receivers to perform multi-signal decoding functionality to remove the required interferers (three overlapping signals) so that high-quality communication, as described in the first part, can be achieved. Various performance graphs are shown for B-FSK and B-PSK for both SIC and PIC techniques. One key finding is that the system performance can be improved substantially to an additional 15% in signal reception success rate by using SIC or PIC. This means that critical information transmitted from 450 aircraft (out of approximately three thousand aircraft in the environment) is preserved and successfully decoded. Multi-signal decoding using these interference cancellation receivers comes at a small penalty of 2 - 4.5 dBs in Eb/No when sufficient signal-to-interference (SIR) ratio (7-12 dB) is provided. / Ph. D.

This thesis presents the results of the development of a user-friendly computer code (in MATLAB) that can be used to calculate co-channel interferences, both in the downlink and in the uplink of a single satellite/space-based mobile communications system, due to the reuse of frequencies in spot beams or coverage cells. The analysis and computer code can be applied to any type of satellite or platform elevated at any height above earth. The cells or beams are defined in the angular domain, as measured from the satellite or the elevated platform, and cell centers are arranged in a hexagonal lattice. The calculation is only for a given instant of time for which the system parameters are input into the program. The results obtained in one program run are for the overall carrier to interference ratio (CIR) along with CIR for both the uplink and downlink paths. An overall carrier to noise plus interference ratio (CNIR) is also calculated, which exemplifies the degradation in the carrier to noise ratio (CNR) of the system. Comparisons for systems with differing system scenarios are also made. For example, overall CIRs are compared for different reuse numbers (3, 4, 7, and 13) in LEO and GEO satellite systems. In conclusion, as expected, it is observed that the co-channel interference generally increases as we decrease the reuse number employed for the frequency reuse in the cells. It is also observed that co-channel interference can cause substantial degradation to the overall CNR of a system. / Master of Science

Master of Science / Department of Electrical and Computer Engineering / William B. Kuhn / Excitement about using ultra-wideband (UWB) technology for networking has grown considerably over the last few years. UWB has several strengths, including high data rates, security, and robustness in multipath environments. Despite these benefits, UWB has been scrutinized for its potential to interfere with narrowband technologies like the Global Positioning System (GPS). Until recently, much of the literature about UWB and GPS compatibility has been published on the basis of theoretical analysis alone. We have investigated the compatibility of UWB and GPS signals using theoretical analysis as well as laboratory measurements with a consumer GPS receiver and a WiMedia UWB device. We conclude from our tests that the UWB device does emit interference in the GPS L1 band, but the interference is low enough that careful antenna and chipset placement could allow UWB and GPS radios to coexist in a single product. Also, we have evaluated several UWB antennas to determine their fitness for use in a handheld electronic product. We find that the antennas’ gain pattern and return loss do not have a significant effect upon the data throughput of the UWB system. Thus, we infer that the indoor environment is highly dispersive and that the UWB system is able to exploit multipath propagation. Furthermore, we have created a link budget to estimate the distances over which a WiMedia UWB system should be capable of operating. In the lab, the maximum distances over which the UWB device actually operated were about half of what we expected. This suggests that the path loss exponent and standard deviation of fading could be higher than we expected or that the implementation loss of the UWB chipset is quite high. Currently the market potential of UWB is uncertain. If UWB is embraced by the consumer electronics industry as the wireless platform of choice for Certified Wireless USB and high-speed Bluetooth technology, it could become a ubiquitous networking feature for electronic products such as phones, laptops, cameras, media players, and portable navigation devices. In this thesis, we strive to provide information that would be useful when undertaking a GPS and UWB radio integration project.

Master of Science / Department of Plant Pathology / John P. Fellers / Harold N. Trick / Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV), are two of the major viruses in the Great Plains of the United States. Cultural practices and mite vector control are the primary methods of disease management; however, they are not fully effective. Resistant varieties are also deployed, although some of the lines present temperature sensitive resistance or negative agronomic properties are linked to resistance. Alternative approaches to viral resistance are needed. RNAi has been shown to play a role in viral defense response and has been successfully used as a biotechnological tool to preprogram viral resistance in transgenic plants. RNAi reduces the expression of specific genes by targeting the accumulation of mRNA. The mechanism is activated by the presence of dsRNA, which is processed into small non-coding sequence that serves as a guide for degrading RNA in a sequence specific manner. In this work, the RNAi approach was used to elicit resistance against WSMV and TriMV. Immature embryos of the wheat cv "Bobwhite" were independently co-transformed with pAHC20, containing the bar gene for glufosinate selection, and either the hairpin construct targeting the coat protein of WSMV or TriMV. After tissue culture, PCR was used to determined the presence of the RNAi CP transgene in putative transformed plants. Eight WSMV and ten TriMV CP RNAi transgenic plants were obtained from the bombardment experiments. Transgenic T1 and T2 seeds were collected and transgene expression was established through RT-PCR. In order to determine viral resistance, T1 and T2 progeny was mechanically inoculated. ELISA results indicated a differential resistance response among the tillers evaluated in each line in T1 generation for both WSMV and TriMV constructs. In T1 generation resistance was seen in up to 60% of the plants evaluated for both constructs, although some events that showed transgene presence did not exhibited resistant phenotype. Analyses of transgene presence and expression in T2 generation evidenced events of transgene silencing and deletion. Regardless of these phenomena, consistent resistance response in two lines of WSMV CP construct and one TriMV CP transgenic line was found.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In a study sponsored by the Air Force Flight Test Center at Edwards AFB, California, Toyon Research Corporation, Goleta, California, demonstrated that shaped pattern antennas could be used to mitigate interference caused by telemetry signals on GPS systems. Using a technique for fixed reception pattern antenna (FRPA) design, Toyon built and tested a GPS antenna that minimizes reception of telemetry signals from a known location.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This paper presents a methodology for the management of interference and spectrum for iNET. It anticipates a need for heavily loaded test environments with Test Articles (TAs) operating over the horizon. In such cases, it is anticipated that fixed and ad hoc networks will be employed, and where spectrum reuse and interference will limit performance. The methodology presented here demonstrates how this can be accomplished in mixed networks.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / As the frequency spectrum becomes more crowded each day, preparation for placement of tracking ground station in tracking environment gains more importance. Existence of high power weather ground radars, airport approach equipment, and various other RF sources in the environment necessitates the test teams to be more cautious. This paper discusses, implemented design changes to an S-band antenna system to reduce the in-band interfering power, calculation of the effects from nearby interferers, analysis of the environment during placement of the mobile ground system by Honeywell telemetry teams.