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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Potential of existing UMTS Signaling Data for Cell Phone Positioning

Akram, Awais, Ahmad, Hamad January 2011 (has links)
In the current era of telecommunication the usage of cellular network has increased rapidly. Number of different new services are introduced i.e. navigation, friend finder, internet browsing, nearby filling stations, shopping centers, traffic information and emergency services. Most of these services are location based and needs the information of particular area to provide the exact services. The addition of location based services in 3G network opens the new ways of using Mobile devices due to which cellular networks has faced number of challenges in providing better positioning accuracy which is the main requirement for location based services. To bear these challenges everyday new ways of finding the accurate position are introduced but most them required upgraded networks or highly equipped terminal. In this thesis the purpose is to find the potential in UMTS signaling data to estimate the position of the user equipment as accurate as possible using the legacy terminals. In this thesis SFN-SFN observed time difference is explored and used in Database Correlation Method (DCM) in network based positioning. This thesis is done by first analyzing the RSCP for the particular area to verify the conditions of FCC. The data is collected in real environment through test drive using TEMS investigation tool and the available measurement reports from the terminal are used to design and implement the DCM Algorithm. Two new approaches are introduced in this thesis SFN-SFN OTD and Hybrid. In Hybrid RSCP and SFN-SFN OTD are used together. In conclusion, the final results from the performed experiments show improvement in estimated position accuracy by Hybrid technique which is a new step in finding the position of user equipment by DCM.
2

Proposition, modélisation et évaluation d'un réseau SFN-MISO pour l'optimisation de la diffusion TNT au standard DVB-T2 / Proposition, modeling and evaluation of a SFN-MISO network for the optimization of TNT broadcasting in DVB-T2

Tormos, Mokhtar 11 June 2012 (has links)
La deuxième génération de la norme de la Télévision Numérique Terrestre (DVB-T2), abréviation de «Digital Video Broadcasting-second generation», a été publiée par l'European Telecommunications Standards Institute (ETSI-EN 302 755) en avril 2009. Elle correspond à une extension de la norme DVB-T actuellement en cours dédiée à la diffusion de la Télévision Numérique Terrestre (TNT). La technologie DVB-T2 a vocation de satisfaire les besoins des diffuseurs terrestres qui désirent, soit de proposer des services numériques inédits lors de l'extinction de la TV analogique (plusieurs programmes TVHD multiplexés), soit d'améliorer la réception sur des téléviseurs portables à l'intérieur des bâtiments ou sur des récepteurs embarqués à bord de véhicules. La norme DVB-T2 est basée sur des principes permettant de mettre en oeuvre des réseaux SFN (Single Frequency Network). Plus précisément, des réseaux de diffusion composés de plusieurs émetteurs et diffusant sur une même fréquence un même signal avec des délais maitrisés. De plus, cette norme DVB-T2 intègre un mécanisme de codage Spatio-fréquentiel de type MISO (Multiple Input Single Output). Ce mode de codage doit améliorer les performances en termes de qualité de réception, du réseau de diffusion par rapport à des réseaux SFN à deux émetteurs, couramment utilisés dans la norme DVB-T. Cependant, à ce jour il y a peu d'évaluations réelles de l'apport d'une diffusion MISO à base de deux antennes et aucune évaluation d'une diffusion MISO dans un réseau SFN à trois ou plusieurs émetteurs. C'est dans ce contexte que se situent ces travaux de thèse. Plus particulièrement, il s'agit d'évaluer les performances des diffusions permettant dans la norme DVB-T2. Parmi les objectifs des travaux présentés dans ce manuscrit, il y a l'exploration et l'évaluation de l'apport d'une solution MISO Alamouti dans un réseau de diffusion combiné ou non à un réseau de type SFN. Nous proposons une nouvelle modélisation d'un réseau au standard DVB-T2 que l'on désigne comme un réseau SFN-MISO. Plusieurs études et résultats de simulation pour des réceptions fixes ou mobiles, ainsi que des analyses détaillées sur les performances d'une distribution MISO Alamouti dans un réseau à fréquence unique (SFN) pour un nombre variable de cas d'antennes, de codage et de modulation, sont donnés. Une exploration et évaluation d'une diversité MISO de type Tarokh est également étudiée et comparée à une approche MISO Alamouti. Le but est de déterminer et d?évaluer les réseaux de diffusion au standard DVB-T2 permettant de nouvelles méthodes de déploiement, de supervision et de diagnostics qui doivent conduire à une meilleure qualité de réception TNT tant fixe que mobile / The second generation of the Digital Terrestrial Television standard (DVB-T2) called "Digital Video Broadcasting-second generation", was published by ETSI (EN 302,755) in April 2009. This new standard is an extension of the DVB-T which is currently used for the broadcast of digital terrestrial television. The DVB-T2 is intended to meet the requirements of terrestrial broadcasters in order to either offer novel digital services after turning off the analogue TV (several HDTV programs by one multiplex) or improve the indoor portable reception of TVs and embedded receivers in vehicles. Digital Terrestrial Television (DTT) is based on SFN (Single Frequency Network) Networks. More precisely, broadcasting networks based on several transmitters which transmit on the same frequency the similar signal with controlled delays. In addition, the standard DVB-T2 proposes an encoding Space-frequency mechanism of type MISO (Multiple Input Single Output). This method of encoding provides improved performance over SFN based on two transmitters. However, there are few real evaluations of the benefit to use a MISO broadcast based on two antennas, and no evaluations of MISO in SFN network based on three and more transmitters. In this context, the works carred out in this thesis consists of evaluating the performances of the different types of broadcasting modes allowed in the standard DVB-T2. Among the objectives, the different types of networks presented in this manuscript, are to explore as far as possible the contribution of solution MISO Alamouti combined or not with SFN broadcast networks. To achieve that, we have proposed a new modeling of DVB-T2 broadcast networks. Several simulation results for fixed and mobile receptions, and detailed performance analysis of the Alamouti diversity in a Single Frequency Network (SFN) for different numbers of antennas, coding and modulation are obtained. Exploration of the MISO-Tarokh technique is also studied and compared with MISO-Alamouti in order to determine and evaluate networks allowing new methods of deployment, monitoring and diagnostic suitable for efficient fixed and mobile terrestrial broadcasting reception
3

Metodologia para implantação de redes de frequência única Single Frequency Network – SFN em televisão digital / Methodology for the implementation of Single Frequency Network - SFN in digital television

Glock, Henry Saute 28 September 2016 (has links)
Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-06-27T22:29:40Z No. of bitstreams: 1 HenrySG_DISSERT.pdf: 34025203 bytes, checksum: 2defdce123ba16681be74520906f9baf (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: Corrigir referência on 2017-07-03T12:20:54Z (GMT) / Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-07-04T16:10:45Z No. of bitstreams: 1 HenrySG_DISSERT.pdf: 34025203 bytes, checksum: 2defdce123ba16681be74520906f9baf (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:56:33Z (GMT) No. of bitstreams: 1 HenrySG_DISSERT.pdf: 34025203 bytes, checksum: 2defdce123ba16681be74520906f9baf (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:59:16Z (GMT) No. of bitstreams: 1 HenrySG_DISSERT.pdf: 34025203 bytes, checksum: 2defdce123ba16681be74520906f9baf (MD5) / Made available in DSpace on 2017-07-04T17:02:35Z (GMT). No. of bitstreams: 1 HenrySG_DISSERT.pdf: 34025203 bytes, checksum: 2defdce123ba16681be74520906f9baf (MD5) Previous issue date: 2016-09-28 / This paper presents a methodology that includes the structure and the care needed to design and implement a Single Frequency Network (SFN), with the benefits of energy conservation, transmitted power, and optimization of coverage area. It shows the network synchronization options and how to adjust the converged signal coverage areas within a region, showing clearly that this technology is a good and safe technological investment option. It also contains a history of one of the greatest technological developments that has occurred, indicating their form and difficulty in analog times. In the theoretical review are evidenced the technical limitations and the actions towards building a new, modern and robust digital transmission technology / Neste trabalho é apresentada uma metodologia que contempla a estrutura e cuidados necessários para projetar e implantar uma Single Frequency Network (SFN), apresentando os benefícios da racionalização de energia, potência transmitida, e otimização das áreas de cobertura. Apresenta as opções de sincronismo de rede bem como ajustar as regiões de cobertura de sinais convergentes a uma mesma região, mostrando com clareza que a tecnologia é uma boa e segura opção de investimento tecnológico. Também contém um histórico de um dos maiores desenvolvimentos tecnológicos já ocorridos, indicando sua forma e dificuldades em épocas analógicas. Na revisão teórica são é evidenciado o porquê das limitações técnicas até então existentes bem como as ações rumo a construção de uma nova, moderna e robusta tecnologia de transmissão digital / 2017-06-27
4

Plánování sítí pro digitální pozemní televizní a rozhlasové vysílání / Network planning for digital terrestrial television and radio broadcasting

Dostal, Radek January 2010 (has links)
Master’s thesis is focused on SFN (Single Frequency Network) and MFN (Multi Frequency Network) networks design in digital television broadcasting based on DVB-T standard and digital radio broadcasting based on T-DAB standard. First part of the thesis is focused on the theoretical description of the MPEG-2 TS transmission, its propagation from transmitter across free space, to be decoded in the DVB-T receiver. In the second, practical part of the thesis, basic parameters of a software package for broadcast network design in RadioLab, RadioBase and Sítě SFN are introduced and the results are displayed on the digital terrain map and morphologic map. Within solution of this thesis was created signal coverage model of DVB-T digital transmitters in entire area of the Czech Republic, so called networks no. 1-4, according to its status in spring 2010, and its future expansion, which is known from TPP (Technical Plan of Conversion) document. At the conclusion of thesis there were made experiments with the modeling of transmitters’ radiated power, guard interval selection and location of DVB-T transmitters in the SFN network.
5

Transmitter Macrodiversity in Multihop Sensor Networks

Saeed, Munawar January 2009 (has links)
<p>Wireless Sensor Network is an emerging technology that has applicationsin Wireless Actuators, remote controlling, distribution of softwareupdates and distribution of parameters to sensor nodes. This projectwork basically covers the concept of macro-diversity. This is a situationin which several transmitters are used for transferring the same signal (inmulti-hop sensor networks) to check the increase in connected nodes orin network coverage. Transmitter macro-diversity increases the receivedsignal strength and thus increases the signal-to-noise ratio which resultsin a lower outage probability. To accomplish this task three differentstrategies have been simulated using thirteen different cases. Broadcastingis used when forming SFN of size one (strategy one) and uni-castingis used for forming SFNs of size two (strategy two) and size three (strategythree).In this project reference material has been gathered frombooks, journals and web sources; and MATLAB has been used as thesimulation tool in which codes are written in the M programming language.The algorithm works firstly by discovering all the nodes that areconnected directly with the Base Station through multi-hoping, afterwhich the second algorithm is applied to check how many more nodescan be reached by forming SFNs. A gain of up to 79% was observedusing strategy one and strategy two and up to 83% in strategy three.The results shows that strategy one (Forming SFNs using BroadcastingTechnique) is the best as more nodes can be reached (for different cases)than for the other two strategies (forming SFNs using uni-casting technique).</p>
6

Design of a DVB-T Receiver : For SFN on a DSP-Processor

Hägglund, Erik January 2012 (has links)
The goal of this thesis was to implement a DVB-T receiver on Coresonic’s DSP-processor and attempt to evaluate how to design a receiver that is robust against very strong echoes with a long delay. Long delayed echoes is very common in Single Frequency Networks (SFN) which is why focus was put on finding algorithms that work well in SFN.The thesis involved analyzing different algorithms involved in making a DVB-T receiver where the focus was to find a good channel estimation algorithm. The thesis also included programming the DSP-processor and making some smaller modifications to their hardware solution to integrate their error correction hardware. After finding relevant articles with promising algorithms a small transmitter, channel and receiver was modeled in Matlab in order to try the different algorithms. After testing the different algorithms some of the simpler ones were first implemented to quickly get a working receiver. The implementation was however time consuming and all of the most appropriate algorithms to better avert the effects of long and strong echoes where not implemented. This means some algorithms where only analyzed and discussed.The receiver performance is tested and simulated in Coresonic’s DSP simulator. The receiver does not fully meet the requirements set by NorDig when it comes to handling long delay spread echoes with a magnitude of 0db when tested in the DSP processor simulator. The receiver is however able to handle the Ricean channel at a SNR of 19 Db and Rayleigh channel at an SNR of 24 Db.This report is the result of the final thesis of a Master of Science in Computer Engineering at Linköpings Tekniska Högskola. The thesis was performed at Coresonic AB in Mjärdevi Linköping.
7

Transmitter Macrodiversity in Multihop Sensor Networks

Saeed, Munawar January 2009 (has links)
Wireless Sensor Network is an emerging technology that has applicationsin Wireless Actuators, remote controlling, distribution of softwareupdates and distribution of parameters to sensor nodes. This projectwork basically covers the concept of macro-diversity. This is a situationin which several transmitters are used for transferring the same signal (inmulti-hop sensor networks) to check the increase in connected nodes orin network coverage. Transmitter macro-diversity increases the receivedsignal strength and thus increases the signal-to-noise ratio which resultsin a lower outage probability. To accomplish this task three differentstrategies have been simulated using thirteen different cases. Broadcastingis used when forming SFN of size one (strategy one) and uni-castingis used for forming SFNs of size two (strategy two) and size three (strategythree).In this project reference material has been gathered frombooks, journals and web sources; and MATLAB has been used as thesimulation tool in which codes are written in the M programming language.The algorithm works firstly by discovering all the nodes that areconnected directly with the Base Station through multi-hoping, afterwhich the second algorithm is applied to check how many more nodescan be reached by forming SFNs. A gain of up to 79% was observedusing strategy one and strategy two and up to 83% in strategy three.The results shows that strategy one (Forming SFNs using BroadcastingTechnique) is the best as more nodes can be reached (for different cases)than for the other two strategies (forming SFNs using uni-casting technique).
8

Histone Deacetylase Inhibitors Trichostatin A (tsa) And Sulforaphane (sfn) Modulate Vitamin D Responsive Cyp24 Gene Expression in 3t3-l1 Preadipocytes

Ahn, Eunjee 01 January 2013 (has links) (PDF)
Vitamin D plays an important role in preserving healthy bones, and has additional roles in the body, including modulation of cell growth, differentiation, neuromuscular and immune function, and anti-inflammatory function. The vitamin D receptor (VDR) is a member of the nuclear hormone receptor superfamily and regulates transcription of vitamin D-dependent target genes, such as those for key proteins involved in calcium and phosphorus absorption and bone development. Histone acetylation weakens the association of histones with DNA, and increases the accessibility of transcriptional regulatory proteins to chromatin templates, thereby increasing transcriptional activity of gene expression. Histone deacetylases remove the acetyl groups and condense chromatin structure, thereby preventing transcription. TSA is a potent histone deacetylase inhibitor and can significantly enhance gene expression. Bioactive food component, sulforaphane (SFN) is found in cruciferous vegetables and is known to be a histone deacetylase inhibitor, leading to transcriptional activation of gene expression. The objective of this study is to demonstrate that the bioactive food components modulate vitamin D action in adipocytes. To investigate the effects of TSA and SFN on vitamin D response, 3T3L1 mouse preadipocytes were treated with the combination of various concentrations of 1,25(OH)2 vitamin D, TSA, and SFN. Upon harvesting cells, the amounts of 24-hydroxylase mRNA, marker of vitamin D response, were measured by semiquantitative reverse transcriptase-PCR analysis. The results showed that the cells treated with 1μM TSA increased 1,25(OH)2 vitamin D-induced CYP24 mRNA level nearly 3.5-fold (p < 0.05) at 1nM 1,25(OH)2 vitamin D and nearly 2.5-fold (p < 0.05) in 10 nM 1,25(OH)2 vitamin D, and the cells treated with 5μM SFN increased 1,25(OH)2 vitamin D-induced CYP24 mRNA level nearly 1.4-fold at 1nM 1,25(OH)2 vitamin D and nearly 1.2-fold at 10 nM 1,25(OH)2 vitamin D.
9

Redes de redistribuição de sinais a partir de redes de freqüência única (SFN)

Novaes, Carolina Duca 10 February 2010 (has links)
Made available in DSpace on 2016-04-18T21:39:49Z (GMT). No. of bitstreams: 2 Carolina Duca Novaes1.pdf: 3168515 bytes, checksum: 4bc2a4d21f8e08b61653940548fcd0d3 (MD5) Carolina Duca Novaes2.pdf: 2186508 bytes, checksum: 51278edae485082fdb365b9e34ad3fda (MD5) Previous issue date: 2010-02-10 / This dissertation presents details of a structure needed to create a Single Frequency Network (SFN) using low-power transmitters, and a comparison with a network composed of a single transmitter with high power. Among the difficulties to implement networks which distribute signals in SFN, has prioritized the synchronization issue and equalization techniques to achieve better performance of this system. Thus, there was a theoretical research comparing the different methods of timing of single frequency networks and simulations of coverage and performance in order to discuss the implementation of such a network system in the Brazilian digital TV (SBTVD). / Este trabalho apresenta um detalhamento da estrutura necessária para se criar uma rede Single Frequency Network (SFN) utilizando transmissores de baixa potência, bem como um comparativo com uma rede composta por um transmissor único de alta potência. Dentre as dificuldades de se implementar as redes de redistribuição de sinais em SFN foi priorizada a questão do sincronismo e técnicas de equalização que permitam um melhor desempenho desse sistema. Para isso foi realizada uma pesquisa teórica comparativa entre os diferentes métodos de sincronismo de redes de frequência única e simulações de cobertura e desempenho, visando discutir a implementação desse tipo de rede no sistema Brasileiro de TV digital (SBTVD).
10

Méthodes algorithmiques pour l'optimisation mono-objectif et multi-objectif : application aux réseaux de radiodiffusion / Algorithmic methods for mono-objective and multi-objective optimization : Application to radio broadcasting networks

Bedoui, Akram 12 November 2015 (has links)
Ma thèse porte sur la configuration dynamique de réseaux de communication radio vérifiant un certain nombre de contraintes (ou objectifs) et l'utilisation, si possible optimale, de l'ensemble des fréquences disponibles à un instant donné. C'est un problème NP-difficile dont l'enjeu économique est important pour l'entreprise TDF. J'ai construit et mis en œuvre des méta-heuristiques hybrides originales pour résoudre ce type de problème et assurer la meilleure qualité de service (QoS) possible. Les fréquences étant une denrée rare et chère, on peut se demander si, pendant un certain temps, une seule fréquence ne suffirait pas pour couvrir les besoins d'un secteur géographique donné. Ceci permettrait d'utiliser les autres fréquences pour d'autres applications. C'est le principe de base des réseaux SFN (Single Frequency Network) qui nécessitent l'optimisation des délais de transmission, le regroupement de certains émetteurs pour construire un tel réseau et le choix de la fréquence à allouer. Du point de vue informatique, il s'agit de réaliser simultanément plusieurs optimisations. La structure d'un réseau SFN doit être ajustable au cours du temps. J'ai développé un logiciel qui réalise ces opérations, à savoir : - sélection des émetteurs pour construire des réseaux (i.e. plaques) SFN, - optimisation des écarts de transmission dans chaque SFN, - choix de la meilleure fréquence possible pour chaque SFN. Les performances de ces algorithmes sont comparées avec la QoS des plans de fréquences utilisés en France et des pays voisins. Les résultats obtenus sont encourageants. / The purpose of my thesis is the dynamic construction of radio communication networks subject to multiple constraints and the optimal (if possible) use of the set of available frequencies at time t. This is an NP-Hard problem with important economical issues. I have designed and used original hybrid meta-heuristics for solving this kind of problems and providing the best possible QoS. Frequencies are rare and expansive therefore we can ask if a single frequency would not be enough, for a while, in order to cover the needs of a given geographical area. This would allow the use of the remaining frequencies for other applications. This is the principle of Single Frequency Networks (SFN) which necessitate the simultaneous optimization of transmission delays, of the allocated frequency and of their design. I have designed an original and e_cient software which performs these operations. We give experimental results for real benchmarks provided by TDF.

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