Dissertations / Theses: 'Damage to the turbo'

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Vertaľ, Peter. "Provoz a údržba vozidel s přeplňovanými motory turbodmychadly." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-232496.

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The goal is to measure the temperature of the turbocharger after engine shutdown.Measurements wants to show the need to keep a car engine to cool after a heavier burden on the idle speed. It would also prevent possible disruptions turbocharger. The paper also deals with the problems, construction and basic principles of operation of the turbocharger

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Šedý, Jakub. "Turbo konvoluční a turbo blokové kódy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219287.

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The aim is to explain the Turbo convolutional and block turbo codes and decoding the secure message. The practical part focuses on the design of a demonstration program in Matlab. The work is divided into four parts. The first two deal with theoretical analysis of coding and decoding. The third section contains a description created a demonstration program that allows you to navigate the process of encoding and decoding. The fourth is devoted to simulation and performance of turbo codes.

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Fournier, Stéphan. "Turbo codes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22763.pdf.

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4

Yan, Yun. "Turbo codes." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175200238.

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Raorane, Pooja Prakash. "Sampling Based Turbo and Turbo Concatenated Coded Noncoherent Modulation Schemes." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1279071861.

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Abbara, Mamdouh. "Turbo-codes quantiques." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00842327.

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L'idée des turbo-codes, construction très performante permettant l'encodage de l'information classique, ne pouvait jusqu'à présent pas être transposé au problème de l'encodage de l'information quantique. En effet, il subsistait des obstacles tout aussi théoriques que relevant de leur implémentation. A la version quantique connue de ces codes, on ne connaissait ni de résultat établissant une distance minimale infinie, propriété qui autorise de corriger un nombre arbitraire d'erreurs, ni de décodage itératif efficace, car les turbo-encodages quantiques, dits catastrophiques, propagent certaines erreurs lors d'un tel décodage et empêchent son bon fonctionnement. Cette thèse a permis de relever ces deux défis, en établissant des conditions théoriques pour qu'un turbo-code quantique ait une distance minimale infinie, et d'autre part, en exhibant une construction permettant au décodage itératif de bien fonctionner. Les simulations montrent alors que la classe de turbo-codes quantiques conçue est efficace pour transmettre de l'information quantique via un canal dépolarisant dont l'intensité de dépolarisation peut aller jusqu'à p = 0,145. Ces codes quantiques, de rendement constant, peuvent aussi bien être utilisés directement pour encoder de l'information quantique binaire, qu'être intégrés comme modules afin d'améliorer le fonctionnement d'autres codes tels que les LDPC quantiques.

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Barros, Jose da Silva. "Codigos turbo quaternarios." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259772.

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Orientador: Renato Baldini Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação
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Mestrado

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Xu, Lei. "OFDM turbo transceivers." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/64480/.

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In this thesis a variety of different techniques designed for the sake of improving the attainable efficiency of wireless system are considered in the context of Orthogonal Frequency Division Multiplexing (OFDM). More explicitly, powerful turbo transceivers invoking Sphere Packing (SP) modulation are designed using EXtrinsic Information Transfer (EXIT) charts for both single-user and multi-user transmission. In order to provide an attractive suite of single-user OFDM transceivers, we contrive a SP-aided OFDM scheme for maximizing the achievable coding advantage. The corresponding capacity equation shows that the SP-OFDM scheme exhibits a higher capacity than its counterpart dispensing with SP. Furthermore, a carefully designed Sphere Packing symbol To Sub-Carrier Mapping (SPTSCM) scheme is contrived, which results in an improved Discrete Input Continuous Output Memoryless Channel (DCMC) capacity. This is achieved by reducing the correlation between the multiple OFDM sub-carriers conveying a specific SP symbol. In order to enhance the attainable BER performance of the SP-OFDM scheme, iterative detection is invoked for exchanging extrinsic information between the SP symbol-to-bit demapper and the channel decoder. In contrast to the classic SP signal construction, sophisticated SP schemes are designed with the aid of EXIT charts for the sake of improving the convergence behaviour of the iteratively detected schemes. Explicitly, an approximately 0.15bit/s/Hz DCMC capacity improvement is achieved and the proposed iterative detection aided SP-OFDM scheme becomes capable of performing within 2.1dB of the maximum achievable rate limit obtained using EXIT charts at BER = 10−4. Some of the proposed advances are then extended to a multi-user Space Division Multiple Access (SDMA) OFDM scheme. Novel turbo MUDs are designed and investigated in terms of their complexity, EXIT characteristics and BER performance. More explicitly, the linear turbo MUDs considered include the Complex-valued Minimum Mean Square Error (SIC-CMMSE) scheme, the Soft Interference Cancellation based Real-valued Minimum Mean Square Error (SIC-RMMSE) arrangement and the Soft Interference Cancellation based Minimum Bit-Error Rate (SIC-MBER) MUD schemes. The SIC-RMMSE is only applicable in the context of BPSK modulated schemes. A Reduced-complexity Minimum Bit-Error Rate (RMBER) is also designed for the sake of arriving at a complexity reduction by slightly compromising the attainable performance in comparison to the SIC-MBER MUD. Furthermore, a hybrid scheme was designed to eliminate the performance degradation imposed by the RMBER MUD. In contrast to above-mentioned linear schemes, Bayesian turbo MUD and the K-best iterative Sphere Decoder (SD) belong to the family of non-linear MUDs. Then a general complexityreduction technique was contrived in order to reduce the complexity imposed by the turbo MUDs, which was referred to as the A-priori-LLR-Threshold (ALT) aided MUD algorithm, which was introduced for the sake of striking an attractive trade-off between the attainable complexity-reduction and the performance degradation imposed. Finally, the novel framework of Transmit Domain Processing based Detectors (TDPD) was contrived for a generalized multi-access or multiplexing based channel model in order to circumvent the exponentially increasing complexity imposed by the Maximum Likelihood (ML) MUD as a function of both the number of antennas and the number of bits per symbol. Explicitly, the TDPD may be separated into three basic steps including the MUD’s Search Center (SC) calculation, detection candidate list generation and LLR output calculation. A range of different schemes were considered for each of the three steps, and the SIC-CMMSE SC aided hybrid K-best subset combination based iterative TDPD was capable of achieving a similar BER performance to the optimal ML detector at a significantly reduced-complexity.

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Mysore, Naveen. "Combined turbo coding and turbo equalization for wireless systems with antenna diversity." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33983.

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Emerging wireless communication systems strive for very high data rates, increased coverage and good quality of service. To achieve these goals under harsh conditions on many wireless channels (e.g., due to fading, multipath interference, power constraints and bandwidth limitations), both antenna diversity schemes and channel coding should be utilized.
This thesis focuses on achieving reliable transmission over a class of multi-input multi-output Rayleigh faded channels at very low Signal-to-Noise Ratios (SNRs). The transmitter and receiver designs are based on turbo coding, multiple transmit/receive antennas and turbo equalization. Simulation studies were performed for systems with different coding rates, numbers of antennas and interleaving strategies. They show the ability to achieve small bit error rates (10-4--10-5) for negative values of SNR.

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Konuskan, Cagatay. "Turbo Equalization for HSPA." Thesis, Linköping University, Department of Electrical Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54640.

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New high quality mobile telecommunication services are offered everyday and the demand for higher data rates is continuously increasing. To maximize the uplink throughput in HSPA when transmission is propagated through a dispersive channel causing self-interference, equalizers are used. One interesting solution, where the equalizer and decoder exchange information in an iterative way, for improving the equalizer performance is Turbo equalization.

In this thesis a literature survey has been performed on Turbo equalization methods and a chosen method has been implemented for the uplink HSPA standard to evaluate the performance in heavily dispersive channels. The selected algorithm has been adapted for multiple receiving antennas, oversampled processing and HARQ retransmissions. The results derived from the computer based link simulations show that the implemented algorithm provide a gain of approximately 0.5 dB when performing up to 7 Turbo equalization iterations. Gains up to 1 dB have been obtained by disabling power control, not using retransmission combining and utilizing a single receiver antenna. The algorithm has also been evaluated considering alternative dispersive channels, Log-MAP decoding, different code rates, number of Turbo equalization iterations and number of Turbo decoding iterations.

The simulation results do not motivate a real implementation of the chosen algorithm considering the increased computational complexity and small gain achieved in a full featured receiver system. Further studies are needed before concluding the HSPA uplink Turbo equalization approach.

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Barros, Jose da Silva. "Codigos turbo hibridos multiniveis." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261099.

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Orientador: Renato Baldini Filho
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação
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Resumo: Neste trabalho apresentamos classes de códigos turbo não binários definidos sobre os campos e anéis de inteiros. Os códigos turbo multiníveis convencionais consistem em dois códigos componentes RSC M-ários, concatenados via um entrelaçador aleatório de N símbolos e com símbolos codificados transmitidos através da modulação M-PSK. Os códigos turbo híbridos multiníveis consistem em dois códigos componentes RSC, não necessariamente definidos sobre o mesmo alfabeto. Os codificadores componentes são separados por um entrelaçador e os símbolos codificados transmitidos através de um esquema híbrido de modulação PSK. O algoritmo de decodificação iterativa de máximo a posteriori, usado para decodificar os códigos concatenados binários, pode ser estendido para a classe dos códigos turbo não binários. Os resultados das simulações mostram que os códigos turbo híbridos multiníveis apresentam melhor desempenho, error floor mais baixo e menor complexidade de codificação e decodificação que os códigos turbo M-ários convencionais. Já os códigos turbo multiníveis M-ários são mais eficientes que os códigos turbo binários padrão
Abstract: This work presents classes of non-binary codes defined over rings and fields of integers. The conventional multilevel turbo codes consist of two M-ary RSC component codes concatenated via a random N-symbol interleaver and with encoded symbols are transmitted using a M-PSK modulation. The hybrid multilevel turbo codes consist of two RSC component codes, defined on different alphabets. The component encoder are separated by a interleaver and the encoder symbols are transmitted utilizing a hybrid M-PSK scheme. The iterative binary decoding algorithm is a maximum a posteriori scheme, which can be extended to the class of the non-binary turbo codes. The results of the simulations show that the hybrid multilevel turbo codes present better performance, lower error floor and lower encoding and decoding complexities than the M-ary conventional turbo codes. Moreover, the M-ary multilevel turbo codes are more efficient than the standard binary turbo codes
Doutorado
Engenharia de Computação
Doutor em Engenharia Elétrica

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12

Ilunga, Lou. "Adaptive, Turbo-coded OFDM." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34578.

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Wireless technologies, such as satellite, cellular, and wireless internet are now commercially driven by ever more demanding consumers, who are ready for seamless integration of communication networks from the home to the car, and into the office. There is a growing need to quickly transmit information wirelessly and accurately. Engineers have already combine techniques such as orthogonal frequency division multiplexing (OFDM) suitable for high data rate transmission with forward error correction (FEC) methods over wireless channels.

In this thesis, we enhance the system throughput of a working OFDM system by adding turbo coding and adaptive modulation (AD). Simulation is done over a time varying, frequency selective Rayleigh fading channel. The temporal variations in the simulated wireless channel are due to the presence of Doppler, a sign of relative motion between transmitter and receiver. The wideband system has 48 data sub-channels, each is individually modulated according to channel state information acquired during the previous burst. The end goal is to increase the system throughput while maintaining system performance under a bit error rate (BER) of 10-2. The results we obtained are preliminary. The lack of resources prevented us from producing detailed graphs of our findings.
Master of Science

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Lee, Kah Ping. "Turbo equalization in wireless communication." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/5844.

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Thesis (M.S.)--University of Missouri-Columbia, 2005.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 11, 2006) Includes bibliographical references.

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Sauvé, Pierre-Paul. "Multibit decoding of turbo codes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0004/MQ40947.pdf.

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Pirestani, Shervin. "Source-controlled block turbo coding." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 69 p, 2008. http://proquest.umi.com/pqdlink?did=994238721&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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SILVA, AMANDA CUNHA. "PERFORMANCE ANALYSIS OF TURBO CODES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9445@1.

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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Códigos turbo são uma técnica de correção de erro eficiente que vem sendo proposta em diversos padrões de comunicações atuais. Esta técnica apresenta um desempenho que se aproxima dos limites teóricos estabelecidos na Teoria de Codificação. A razão para o excelente desempenho deste tipo de código baseia-se em dois fatores: uma estrutura de codificação composta por codificadores concatenados e uma estrutura de decodificação iterativa. Neste trabalho é realizada uma revisão da literatura onde a decodificação turbo é discutida segundo duas abordagens: uma que baseia-se na estrutura dos codificadores empregados e outra baseada na moderna teoria de grafos- fatores. O desempenho destes códigos é avaliado através de simulações. São considerados fatores como a estrutura dos codificadores, o tipo de modulação empregada, o algoritmo de decodificação utilizado, entre outros.
Turbo codes are an efficient error correcting technique that has been proposed for many communications standards. This technique achieves a performance that is near the theoretical limits established by Information Theory. The reason for this excellent performance of turbo codes relies on two aspects: a coding structure that is composed by concatenated encoders and an iterative decoding procedure. In the literature, two approaches for turbo decoding are presented: one that is based on the encoder structure and another that is built around the factor graphs theory. Both approaches are discussed in this work. Performance evaluation for these codes are obtained through simulations. Some aspects such as encoder structure, modulation scheme and decoding algorithm are considered and evaluated. Also codes derived from turbo codes by puncturing and shortening have been studied in this work.

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Said, Fatin. "Turbo coding from OFDM systems." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394250.

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Podemski, Robert. "Analyse spectrale des turbo codes." Rennes 1, 1998. http://www.theses.fr/1998REN10150.

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Cette these est dediee aux proprietes spectrales des turbo-codes. Un nouvel algorithme de calcul du spectre des distances de hamming, appele algorithme de la fenetre coulissante, est propose. Cet algorithme est base sur l'algorithme de fano et utilise le concept de suite de retour a zero introduit dans cette these. L'algorithme de la fenetre coulissante tire avantage des proprietes des turbo-codes et, de ce fait, presente une complexite bien inferieure a celle de l'algorithme de fano, permettant ainsi le calcul du spectre des distances pour des turbo-codes utilisant un entrelacement pouvant atteindre 4. 000 bits. La seconde partie de la these donne les regles de construction de turbo-codes, presentant de bons spectres de distance. Les differents criteres que doivent remplir les elements constitutifs du turbo-codeur i. E. Les codes recursifs systematiques, l'entrelacement et le masque de poinconnage de facon a obtenir de bonnes performances sont alors donnes. Les resultats analytique sont verifies par la simulation, aussi bien dans le cas du decodage optimal que non-optimal (iteratif).

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Shukurov, Nadir. "Geometrical Design of Turbo Roundabout." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23336/.

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The Turbo Roundabout is a roundabout fitted with spiral roads to efficiently counteract the complexities of the modern multilane roundabout. This roundabout has an edge over cutting-edge roundabouts regarding capacity and safety and was first invented by Professor Fortujin in 1996. Fast driving speeds and many possible conflicts at multilane roundabout approaches, exits and circulatory roadways are the reasons for this type of construction project. Road designers have been attempting to address these issues over the past few years by implementing new roundabout configurations. Turbo-roundabouts have also spread outside of the Netherlands over the last decade, mainly in Eastern Europe and Germany, but also in North America. While the Dutch model for turbo-roundabout design was strictly applied by some nations, others designed them on experimental sites, resulting in geometrical variations unique to the area. We have more than 390 turbo-roundabouts worldwide today. In this paper, the measurement of sight distance on turbo roundabouts with an emphasis on “Intersection Sight Distance” to conflicting vehicle circulation will be studied. The traditional graphical approach has been supplemented with the analytical solution consisting of derivation of generalized mathematical equations for intersection sight distance for conflicting circulating vehicle at turbo roundabout. To determine the design of turbo roundabout instead of standard type we collected numbers, iterations, flow rate and other information from the intersection in Neapol street - M.Hadi-Ashig Alaskar and Vungtau streets in the capital of Azerbaijan, Baku city. The current name of circle is “Ukraine circle” on behalf of friendship between Azerbaijan and Ukraine. Some of these collected specimens were used to perform the by using the software test at the University of Bologna and in Baku Transportation Agency by PTV VISSIM simulation and AutoCAD Civil.

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Ploštica, Stanislav. "Turbo kódy a jejich aplikace." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218201.

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This Diploma thesis aims to explain the data coding using turbo codes. These codes belong to the group of error correction codes. We can reach the high efficiency using these codes. The first part describes process of encoding and decoding. There are describes parts of encoder and decoder. Principle of encoding and decoding demonstrate a simple example. The end of this part contains description of two most frequently used decoding algorithms (SOVA and MAP). The second part contains description of computer program that was made for using as teaching aid. This program was created in Matlab GUI. This program enables to browse error correction process step by step. This program contains graphic interface with many options and display results. In the third part is described program created in Matlab Simulink that was implemented into the TMS320C6713 kit and there is description of measuring procedure. For verification of efficiency of turbo codes was measured any parameters. Some of these parameters are: number of decoding iterations, generating polynoms and using of puncturing. The last part contains measured value and result evaluation.

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Smělý, Martin. "Návrhové prvky turbo-okružních křižovatek." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-355603.

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Dissertation describes new methodology of design turbo-roundabouts in Czech Republic. Especially innovative is approach to the design of traffic lanes with regards to standard vehicles and widening of traffic lanes according to their dimensions. Innovative is also approach to road signs, where details of current signs are modified, however, these details are important for drivers’ better understanding while driving through turbo-roundabouts. Dissertation fills legislative, but also technical, blank spot during turbo-roundabouts design and I believe that it will benefit particularly designers of these intersections.

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Allala, Prathyusha. "Genetic Optimization of Turbo Decoder." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1293681661.

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Tong, Yanhui. "VHDL implementation of turbo codec." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26405.

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Turbo coding is one of the most significant achievements in coding theory during the last decade. It has been shown in the literature that transmission systems employing turbo codes could achieve a performance close to the Shannon limit. Turbo decoding is the major contributor to the overall complexity of turbo coding. Therefore, the challenge is to implement turbo coding in various communications systems at affordable decoding complexity using current VLSI technology. Four different turbo decoding algorithms were investigated in this thesis. Comparisons on both their performances and implementation complexities were performed. Log-MAP based turbo decoding offers the best compromise among the different turbo decoding algorithms. A Register-Transfer-Level (RTL) fixed-point turbo decoder model based on Log-MAP algorithm was designed and simulated using VHDL as the hardware description language. The RTL model was verified by comparing its simulation results with those obtained from a behavioral model of the same turbo decoder written in C language.

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Shaw, Christopher, and Michael Rice. "TURBO-CODED APSK FOR TELEMETRY." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604473.

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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
This paper considers the use of Amplitude-Phase Shift Keying (APSK) for a telemetry system. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. We discuss compensation techniques for power amplifier nonlinearities. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in telemetry standards.

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Rodrigo, Clinton. "Basic Comparison of Three Aircraft Concepts: Classic Jet Propulsion, Turbo-Electric Propulsion and Turbo-Hydraulic Propulsion." Master's thesis, Aircraft Design and Systems Group (AERO), Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, 2019. http://d-nb.info/1204558019.

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Purpose - This thesis presents a comparison of aircraft design concepts to identify the superior propulsion system model among turbo-hydraulic, turbo-electric and classic jet propulsion with respect to Direct Operating Costs (DOC), environmental impact and fuel burn. --- Approach - A simple aircraft model was designed based on the Top-Level Aircraft Requirements of the Airbus A320 passenger aircraft, and novel engine concepts were integrated to establish new models. Numerous types of propulsion system configurations were created by varying the type of gas turbine engine and number of propulsors. --- Findings - After an elaborate comparison of the aforementioned concepts, the all turbo-hydraulic propulsion system is found to be superior to the all turbo-electric propulsion system. A new propulsion system concept was developed by combining the thrust of a turbofan engine and utilizing the power produced by the turbo-hydraulic propulsion system that is delivered via propellers. The new partial turbo-hydraulic propulsion concept in which 20% of the total cruise power is coming from the (hydraulic driven) propellers is even more efficient than an all turbo-hydraulic concept in terms of DOC, environmental impact and fuel burn. --- Research Limitations - The aircraft were modelled with a spreadsheet based on handbook methods and relevant statistics. The investigation was done only for one type of reference aircraft and one route. A detailed analysis with a greater number of reference aircraft and types of routes could lead to other results. --- Practical Implications - With the provided spreadsheet, the DOC and environmental impact can be approximated for any commercial reference aircraft combined with the aforementioned propulsion system concepts. --- Social Implications - Based on the results of this thesis, the public will be able to discuss the demerits of otherwise highly lauded electric propulsion concepts. --- Value - To evaluate the viability of the hydraulic propulsion systems for passenger aircraft using simple mass models and aircraft design concept.

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Gulmez, Baskoy Ulku. "A Turbo Detection Scheme For Egprs." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1259415/index.pdf.

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Enhanced Data Rates for Global Evolution (EDGE) is one of the 3G wireless communication standards, which provides higher data rates by adopting 8-PSK modulation in TDMA system infrastructure of GSM. In this thesis, a turbo detection receiver for Enhanced General Packet Radio Services (EGPRS) system, which is the packet switching mode of EDGE, is studied. In turbo detection, equalization and channel decoding are performed iteratively. Due to 8-ary alphabet of EGPRS modulation, full state trellis based equalization, as usually performed in GSM, is too complex not only for turbo detection but even for conventional equalization
so suboptimum schemes have to be considered. The Delayed Decision Feedback Sequence Estimation (DDFSE) is chosen as suboptimal and less complex trellis based scheme and it is examined as a conventional equalization technique firstly. It is shown that the DDFSE has a fine tradeoff between performance and complexity and can be a promising candidate for EGPRS. Then it is employed to reduce the number of the trellis state in turbo detection. Max-log-MAP algorithm is used for soft output calculations of both SISO equalizer and SISO decoder. Simulation results illustrate that proposed turbo detection structure improves bit error rate and block error rate performance of the receiver with respect to the conventional equalization and decoding scheme. The iteration gain varies depending on modulation type and coding rate of Modulation Coding Scheme (MCS) employed in EGPRS.

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Narayanan, Krishna Rama. "Turbo decoding for packet data systems." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/14844.

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Sazli, Murat Husnu Işık Can. "Neural network applications to turbo decoding." Related Electronic Resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2003. http://wwwlib.umi.com/cr/syr/main.

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Lindblom, Johannes. "Turbo Decoding With Early State Decisions." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11694.

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Turbo codes was first presented in 1993 by C. Berrou, A. Glavieux and P. Thitimajshima. Since then this class of error correcting codes has become one of the most popular, because of its good properties. The turbo codes are able to come very close to theoretical limit, the Shannon limit. Turbo codes are for example used in the third generation of mobile phone (3G) and in the standard IEEE 802.16 (WiMAX).

There are some drawbacks with the algorithm for decoding turbo codes. The deocoder uses a Maximum A Posteriori (MAP) algorithm, which is a complex algorith. Because of the use of many variables in the decoder the decoding circuit will consume a lot of power due to memory accesses and internal communication. One way in which this can be reduced is to make early decisions.

In this work I have focused on making early decision of the encoder states. One major part of the work was also to be sure that the expressions were written in a way that as few variables as possible are needed. A termination condition is also introduced. Simulations based on estimations of the number of memory accesses, shows that the number of memory accesses will significantly decrease.

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Osseiran, Afif Hani. "Sur le décodage des codes turbo." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0028/MQ49797.pdf.

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Lajnef, Khaled. "Étude des performances des codes turbo." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ65584.pdf.

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Tanriover, Cagri C. "Improved turbo codes for data transmission." Thesis, Lancaster University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288960.

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Shah, Chintan P. "Turbo-based recievers for underwater communications." Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531757.

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Von, Backstrom Theodor W. "From turbo-machines to solar chimneys." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71762.

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Thesis (PhD)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: This dissertation is basically a summary, with some interpretation, of published research by the author. The scope is limited to the fields of turbo-machinery, computational fluid dynamics and solar chimney power plants. The main contribution in the field of turbo-machinery in general is in the development of a through-flow method that automatically satisfies mass conservation. Concerning fan design, the contributions are the realization of the importance of the exit kinetic energy in the determination of the efficiency of rotor-only axial flow fans, and the quantification of the effect of off-axis inflow into cooling system fans on their performance. In the field of centrifugal fans and compressors an original, unifying model for the prediction of slip factor was developed. To investigate accident scenarios in closed cycle gas turbine nuclear reactors, all possible operational modes of multi-stage axial compressor operation caused by flow and rotation direction were investigated experimentally and computationally. Spanning the fields of turbo-machinery and solar chimneys, the basic theory of solar chimney turbines was developed, showing that high turbine efficiency was possible. In the field of solar chimneys, an original thermodynamic approach was developed to predict the main relationships that govern solar chimney performance, and to solve the through-flow equations for non-ideal systems with losses. Equations for the accurate determination of all the thermodynamic variables in a solar chimney as dependent on chimney height, wall friction, additional losses, internal drag and area change were derived and solved. Coefficients of wall friction, bracing wheel loss and exit kinetic energy were determined experimentally, and empirical equations were developed to predict the loss coefficient of the collector to turbine transition section and and the turbine inlet flow angle. A simple power law approach allowed the calculation of the optimal turbine pressure drop in solar chimney power plants. A comparison of two sets of equations used to calculate the heat fluxes into, inside and leaving the solar collector, resulted in similar air temperature rises in the collector, and similar produced power. It turned out however that the optimal flow for minimal turbine pressure drop was dependent on the heat transfer models. Investigation of the performance of various solar chimney turbo-generator layouts using analytical models and optimisation techniques showed that the optimal number of turbines varies with plant size, but the individual turbine size, the number of blades and even the efficiency remains close to constant. It was found that the cost of a turbogenerator system, however, varies significantly with size. A joint paper with several German universities and institutions did a comparative cost analysis of solar chimney power plants
AFRIKAANSE OPSOMMING: Hierdie verhandeling is basies ’n opsomming, met interpretasie, van gepubliseerde navorsing deur die outeur. Die omvang is beperk tot die gebiede van turbomasjinerie, berekeningsvloeidinamika en sonskoorsteenkragstasies. Die hoof bydrae op die gebied van turbomasjinerie in die algemeen is in die ontwikkeling van ’n deurvloeimetode wat outomaties massabehoud bevredig. Wat waaierontwerp betref is die bydrae die besef van die belangrikheid van die uitlaat kinetiese energie in die bepaling van waaierbenuttingsgraad, en die kwantifisering van die effek van af-as invloei in verkoelingswaaiers op hulle gedrag. Op die gebied van sentrifugaalwaaiers en -kompressors is ’n oorspronklike, samevattende model vir die voorspelling van glipfaktor ontwikkel. Om ongeluk-scenario’s in geslote kringloop gasturbine kenreaktors te ondersoek is al die moontlike werksmodusse veroorsaak deur vloei en rotasie rigting van ’n multistadium aksiaalkompressor eksperimenteel en numeries ondersoek. As brug tussen turbomasjinerie en sonskoorstene is die basiese teorie van sonskoorsteenturbines ontwikkel met die aanduiding dat hoë turbine benuttingsgraad moontlik is. Op die gebied van sonskoorstene is ’n oorspronklike termodinamies benadering ontwikkel om die hoofverwantskappe te voorspel wat sonskoorsteen gedrag bepaal, en om die deurvloei vergelykings op te los vir nie-ideale stelsels met verliese. Vergelykings vir die akkurate bepaling van al die termodinamiese veranderlikes in ’n sonskoorsteen soos afhanklik van skoorsteenhoogte, wandwrywing, bykomstige verliese, interne sleur en oppervlakte verandering is afgelei en opgelos. Koëffisiënte vir wandwrywing, verstywingswiel-verlies en uitlaat kinetiese energie is eksperimenteel bepaal, en empiriese vergelykings is ontwikkel om die verlieskoëffisiënt van die kollektor-tot-skoorsteen oorgang en die turbine inlaatvloeihoek te bepaal. ’n Eenvoudige magswet benadering het dit mootlik gemaak om die optimum turbine-drukval in sonskoorsteen aanlegte te bepaal. ’n Verglyking van twee stelle vergelykings om warmtevloede in, binne en uit die sonkollektor te bereken het gelei na soortgelyke temperatuurstygings en gelewerde drywing. Die optimale vloei vir maksimum drywing was egter afhanklik van die warmteoordrag modelle. Ondersoek van die gedrag van verskeie turbo-generator uitlegte, deur gebruik van analitiese modelle en optimeringstegnieke het getoon dat die optimale aantal turbines wissel met aanleg grootte, maar die individuele turbine grootte, die aantal lemme en selfs die benuttingsgraad bly feitlik konstant. Daar is egter gevind dat die koste van ’n turbogenerator stelsel beduidend wissel met grootte. ’n Gesamentlike artikel met verskeie Duitse universiteite en instansies het ’n vergelykende koste analise van sonskoorstene gedoen.

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Hebbes, Luke. "Turbo codes for real-time applications." Thesis, Kingston University, 2004. http://eprints.kingston.ac.uk/20726/.

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Kurkoski, Brian M. "Algorithms and schedules for turbo equalization /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3137222.

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Souvignier, Thomas Victor. "Turbo decoding for partial response channels /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9938584.

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Hinton, Danielle A. (Danielle Ayodele) 1978. "Turbo coding in correlated fading channels." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87214.

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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (leaves 46-47).
by Danielle A. Hinton.
M.Eng.

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Nordlöf, Anon, and John Lundqvist. "Turbo Heat Transfer Modeling for Control." Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150352.

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The demand for lower emission engines forces the car industry to build moreefficient engines. Turbocharged engines are on the rise, and better understandingof the heat transfer and efficiency of the turbocharger is needed to build better ones. A lot is known about the overall efficiency of the turbocharger, but not much is known about where the heat losses are located and how they interact with each other. This thesis presents a one dimensional model for heat exchange in the tur-bocharger and investigates how the heat flows from the hot exhaust gases to the cold intake air. Data is gathered by performing tests on a single scroll turbocharger in an engine test bench at Linköping University. The tests are focused on operating points where the air mass flow is low and neither the compressor nor the turbine works adiabatically. The results show that it is possible to estimate the heat flows together withthe efficiency of the turbine and compressor using only known parameters, elim-inating the need to add any new sensors to the engine.

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Jar, e. Silva Marcel. "Projeto de entrelaçadores para códigos turbo." Universidade Federal de Pernambuco, 2006. https://repositorio.ufpe.br/handle/123456789/5871.

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Made available in DSpace on 2014-06-12T17:42:14Z (GMT). No. of bitstreams: 2 arquivo6945_1.pdf: 934856 bytes, checksum: 6dde6929102773555ee9224146f061b8 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006
Os entrelaçadores possuem um papel crucial para que os códigos turbo atinjam desempenho próximo da capacidade do canal. Apesar de terem sido introduzidos primeiramente como simples permutações aleatórias, atualmente existem várias classes de entrelaçadores, tais como, S-aleatórios, DRP, polinomiais e quasi-cíclicos, que produzem melhor desempenho para códigos turbo em um canal AWGN e/ou são mais simples de serem armazenados. Este trabalho tem dois objetivos principais. O primeiro é fazer estudos comparativos entre classes de entrelaçadores que apresentam a propriedade da economia de memória em relação aos entrelaçadores aleatórios. Este estudo visa suprir uma lacuna na literatura, que normalmente compara novas classes de entrelaçadores com a classe dos entrelaçadores S-aleatórios. O segundo objetivo é o desenvolvimento de uma nova classe de entrelaçadores que também apresenta a característica da economia de memória, além de garantir altos fatores de espalhamento. Os entrelaçadores pertencentes a esta classe são batizados como entrelaçadores quasi-retangulares

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Faudeil, Stéphane. "Les turbo-codes à haut débit." Brest, 1994. http://www.theses.fr/1994BRES2019.

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Les turbo-codes constituent une nouvelle classe de codes correcteurs d'erreurs elaboree a partir d'une concatenation parallele de 2 codes convolutifs systematiques recursifs a faible nombre d'etats separes par un entrelaceur. Leur decodage, realise sous forme iterative, conduit a des performances superieures a celles de tout autre code correcteur. Le processus iteratif se traduit en pratique par une structure modulaire de decodage. Le module etant d'une complexite limitee, les problemes de dissipation aux hautes frequences sont evacues. Les turbo-codes semblent donc etre bien adaptes aux applications a haut debit (> 150 moits/s). Le travail de these a porte sur l'etude d'architectures paralleles permettant d'atteindre ces debits eleves. Le temps d'acces des memoires ram utilisees dans les entrelaceurs limite la frequence de fonctionnement du turbo-codeur/decodeur. Un entrelacement parallele, de performances identiques a celles de l'entrelaceur classique, a ete imagine, pour en diminuer artificiellement les temps critiques. Une seconde contrainte temporelle apparait dans les deux decodeurs de viterbi a decisions ponderees presents dans le module. Trois solutions sont proposees: l'utilisation de l'arithmetique carry save dans les processeurs acs (add compare select), le traitement de deux etapes de treillis en une seule recursion des processeurs acs, le decodage de facon concurrente de 2 ou 3 sequences independantes et alternees. Une comparaison de performances (complexite, vitesse et dissipation) permet de degager la seconde solution comme etant la plus appropriee. Pour un debit de transmission de 150 moits/s, sur la base d'une technologie cmos 0. 6 , la puissance dissipee par le module est de 2. 2 w, et la surface occupee (cur du circuit) est de 30 mm#2

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Raouafi, Fathi. "Adéquation turbo codes/processeurs de signal." Brest, 2001. http://www.theses.fr/2001BRES2010.

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Roumy, Aline. "Egalisation et décodage conjoints : méthodes turbo." Cergy-Pontoise, 2000. http://biblioweb.u-cergy.fr/theses/00CERG0100.pdf.

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Afin d'assurer des transmissions fiables et a debit eleve, les recepteurs utilisent le decodage de canal mais doivent egalement combattre les interferences entre symboles apportees par les canaux selectifs en frequence. Si pour des raisons de complexite, les recepteurs classiques operent l'egalisation et le decodage de maniere disjointe, cette approche n'est pas optimale. Aussi, nous nous sommes interesses a des techniques d'egalisation et de decodage conjoints mais sous-optimales pour maintenir une complexite reduite. Ainsi, nous avons etudie le turbo-egaliseur, qui applique le principe iteratif des turbo-codes a notre contexte. Afin de mettre en evidence la perte due a la sous-optimalite du turbo-egaliseur, nous avons calcule les performances asymptotiques de la solution optimale (au sens map) au probleme de l'egalisation et du decodage conjoints et avons montre qu'elles peuvent differer de la borne babg code. Puis, nous avons propose une analyse fonctionnelle du processus iteratif qui permet de predire les performances et en particulier le point de declenchement de l'effet turbo. Cette analyse a egalement montre que le modele blanc gaussien est insuffisant pour representer l'erreur a l'entree du decodeur. Nous avons ensuite etendu l'approche de la turbo-egalisation a la detection multi-utilisateurs, qui traite les interferences entre symboles mais aussi entre utilisateurs. Cette generalisation a conduit a une premiere structure, que nous avons ensuite amelioree sans augmenter la complexite. Pour ce faire, nous avons propose d'une part un nouvel ordre de demodulation des utilisateurs, qui tient compte des interferences et d'autre part une nouvelle structure serie appelee full.

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Baker, Alan T. "Turbo-discharging the internal combustion engine." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16337.

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This thesis reports original research on a novel internal combustion (IC) engine charge air system concept called Turbo-Discharging. Turbo-Discharging depressurises the IC engine exhaust system so that the engine gas exchange pumping work is reduced, thereby reducing fuel consumption and CO2 emissions. There is growing concern regarding the human impact on the climate, part of which is attributable to motor vehicles and transport. Recent legislation has led manufacturers to improve the fuel economy and thus reduce the quantity of CO2 generated by their vehicles. As this legislation becomes more stringent manufacturers are looking to new and developing technologies to help further improve the fuel conversion efficiency of their vehicles. Turbo-Discharging is such a technology which benefits from the fact it uses commonly available engine components in a novel system arrangement. Thermodynamic and one-dimensional gas dynamics models and experimental testing on a 1.4 litre four cylinder four-stroke spark ignition gasoline passenger car engine have shown Turbo-Discharging to be an engine fuel conversion efficiency and performance enhancing technology. This is due to the reduction in pumping work through decreased exhaust system pressure, and the improved gas exchange process resulting in reduced residual gas fraction. Due to these benefits, engine fuel conversion efficiency improvements of up to 4% have been measured and increased fuel conversion efficiency can be realised over the majority of the engine operating speed and load map. This investigation also identified a measured improvement in engine torque over the whole engine speed range with a peak increase of 12%. Modelling studies identified that both fuel conversion efficiency and torque can be improved further by optimisation of the Turbo-Discharging system hardware beyond the limitations of the experimental engine test. The model predicted brake specific fuel consumption improvements of up to 16% at peak engine load compared to the engine in naturally aspirated form, and this increased to up to 24% when constraints imposed on the experimental engine test were removed.

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Rowitch, Douglas Neal. "Convolutional and turbo coded multicarrier direct sequence CDMA, and applications of turbo codes to hybrid ARQ communication systems /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9835385.

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46

Kim, Hasung. "Turbo-Like Coding for Spread-Spectrum Communications." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4815.

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This thesis studies advanced error control schemes using turbo-like codes, turbo-like coded modulations, turbo hybrid-ARQ (Automatic Repeat reQuest) schemes, and rate compatible puncturing techniques for reliable and adaptive commercial and tactical spread-spectrum communications, especially for code-division multiple access (CDMA) cellular systems and direct-sequence (DS) and frequency-hopping (FH) anti-jam systems. Furthermore, we utilize both the maximum-likelihood (ML) bounding techniques and convergence analysis to design and analyze various turbo-like coding schemes that show different behaviors in error performance from conventional trellis coding schemes. In the area of DS-CPM, we propose a DS concatenated coded CPM system for pulse-noise jamming channels and an anti-jam iterative receiver utilizing jammer state information. We also design a mixed concatenated CPM system that mixes CPM schemes with different convergence characteristics. In addition, we present the ML bound and convergence analysis for the jamming channel. In the area of FH-CPM, we propose anti-jam serially concatenated slow FH-CPM systems, whose phase is continuous during each hop interval, along with coherent and non-coherent iterative receivers. We also propose an iterative jamming estimation technique for the iterative receiver. In the area of multi-h CPM, we propose a power- and bandwidth-efficient serially concatenated multi-h CPM along with an appropriate iterative receiver structure. Serially concatenated multi-h CPM is shown to outperform single-h CPM. To design adaptive and versatile error control schemes using turbo-like codes for packet-data networks, we propose turbo hybrid-ARQ (HARQ) and rate compatible puncturing techniques for retransmission. In the area of turbo hybrid-ARQ, we propose a Type-I turbo HARQ scheme using a concatenated RS-turbo code and a packet combining technique for W-CDMA system to improve the performance of error and decoding latency. The W-CDMA system including the fast power control and coherent Rake receiver with a channel estimation technique for multipath fading channels is considered. Finally, in the area of rate compatible punctured turbo-like codes, we propose rate compatible punctured turbo (RCPT) codes and rate compatible punctured serially concatenated convolutional (RCPS) codes along with their puncturing methods. In addition, we propose Type-II RCPT-HARQ and RCPS-HARQ schemes to perform an efficient incremental redundancy retransmission.

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List, Nancy Brown. "Low-Complexity Interleaver Design for Turbo Codes." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5096.

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A low-complexity method of interleaver design, sub-vector interleaving, for both parallel and serially concatenated convolutional codes (PCCCs and SCCCs, respectively) is presented here. Since the method is low-complexity, it is uniquely suitable for designing long interleavers. Sub-vector interleaving is based on a dynamical system representation of the constituent encoders employed by PCCCs and SCCCs. Simultaneous trellis termination can be achieved with a single tail sequence using sub-vector interleaving for both PCCCs and SCCCs. In the case of PCCCs, the error floor can be lowered by sub-vector interleaving which allows for an increase in the weight of the free distance codeword and the elimination of the lowest weight codewords generated by weight-2 terminating input sequences that determine the error floor at low signal-to-noise ratios (SNRs). In the case of SCCCs, sub-vector interleaving lowers the error floor by increasing the weight of the free distance codewords. Interleaver gain can also be increased for SCCCs by interleaving the lowest weight codewords from the outer into non-terminating input sequences to the inner encoder. Sub-vector constrained S-random interleaving, a method for incorporating S-random interleaving into sub-vector interleavers, is also proposed. Simulations show that short interleavers incorporating S-random interleaving into sub-vector interleavers perform as well as or better than those designed by the best and most complex methods for designing short interleavers. A method for randomly generating sub-vector constrained S-random interleavers that maximizes the spreading factor, S, is also examined. The convergence of the turbo decoding algorithm to maximum-likelihood decisions on the decoded input sequence is required to demonstrate the improvement in BER performance caused by the use of sub-vector interleavers. Convergence to maximum-likelihood decisions by the decoder do not always occur in the regions where it is feasible to generate the statistically significant numbers of error events required to approximate the BER performance for a particular coding scheme employing a sub-vector interleaver. Therefore, a technique for classifying error events by the mode of convergence of the decoder is used to illuminate the effect of the sub-vector interleaver at SNRs where it is possible to simulate the BER performance of the coding scheme.

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Gazi, Orhan. "Parallelized Architectures For Low Latency Turbo Structures." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608110/index.pdf.

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In this thesis, we present low latency general concatenated code structures suitable for parallel processing. We propose parallel decodable serially concatenated codes (PDSCCs) which is a general structure to construct many variants of serially concatenated codes. Using this most general structure we derive parallel decodable serially concatenated convolutional codes (PDSCCCs). Convolutional product codes which are instances of PDSCCCs are studied in detail. PDSCCCs have much less decoding latency and show almost the same performance compared to classical serially concatenated convolutional codes. Using the same idea, we propose parallel decodable turbo codes (PDTCs) which represent a general structure to construct parallel concatenated codes. PDTCs have much less latency compared to classical turbo codes and they both achieve similar performance. We extend the approach proposed for the construction of parallel decodable concatenated codes to trellis coded modulation, turbo channel equalization, and space time trellis codes and show that low latency systems can be constructed using the same idea. Parallel decoding operation introduces new problems in implementation. One such problem is memory collision which occurs when multiple decoder units attempt accessing the same memory device. We propose novel interleaver structures which prevent the memory collision problem while achieving performance close to other interleavers.

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Unal, Baris. "Robust Data Hiding Scheme With Turbo Codes." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606848/index.pdf.

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ABSTRACT ROBUST DATA HIDING SCHEME WITH TURBO CODES Ü
NAL, BariS M.S., Department of Electrical And Electronics Engineering Supervisor: Prof. Dr. Rü
yal ERGÜ
L December 2005, 127 pages This study describes the design and implementation of a robust data hiding algorithm which is provided by turbo codes. As the digital technology grows up, it is getting easy to copy and distribute multimedia products without getting legal permission. This has forced researchers to study in digital watermarking areas. Along with watermarking researches, data hiding studies have gained interest in the last decade. Different watermark and data hiding algorithms have been proposed considering different requirements and properties such as robustness, fidelity, invisibility and data hiding capacity. In this thesis, robustness of watermarking systems and fidelity requirement in watermark models are considered and use of turbo codes is proposed with data embedding systems to improve system performance in terms of robustness. Fundamental watermarking algorithms in DCT domain are analyzed and simulated. Their performances in terms of robustness are presented. Data hiding algorithm which is based on projection and perturbation in transform domain is implemented in visual C. Then turbo codes are applied to this algorithm to improve system robustness. Improvement provided by turbo codes is demonstrated and compared with other discussed watermarking systems.

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Haj, Shir Mohammadi Atousa. "Application of Turbo-Codes in Digital Communications." Thesis, University of Waterloo, 2001. http://hdl.handle.net/10012/773.

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This thesis aims at providing results and insight towards the application of turbo-codes in digital communication systems, mainly in three parts. The first part considers systems of combined turbo-code and modulation. This section follows the pragmatic approach of the first proposed such system. It is shown that by optimizing the labeling method and/or modifying the puncturing pattern, improvements of more than 0. 5 dB insignal to noise ratio (SNR) are achieved at no extra cost of energy, complexity, or delay. Conventional turbo-codes with binary signaling divide the bit energy equally among the transmitted turbo-encoder output bits. The second part of this thesis proposes a turbo-code scheme with unequal power allocation to the encoder output bits. It is shown, both theoretically and by simulation, that by optimizing the power allocated to the systematic and parity check bits, improvements of around 0. 5 dB can be achieved over the conventional turbo-coding scheme. The third part of this thesis tackles the question of ``the sensitivity of the turbo-code performance towards the choice of the interleaver'', which was brought up since the early studies of these codes. This is the first theoretical approach taken towards this subject. The variance of the bound is evaluated. It is proven that the ratio of the standard deviation over the mean of the bound is asymptotically constant (for large interleaverlength, N), decreases with N, and increases with SNR. The distribution of the bound is also computationally developed. It is shown that as SNR increases, a very low percentage of the interleavers deviate quite significantly from the average bound but the majority of the random interleavers result in performances very close to the average. The contributions of input words of different weights in the variance of performance bound are also evaluated. Results show that these contributions vary significantly with SNR and N. These observations are important when developing interleaver design algorithms.

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