Cellular Telephony
Mostrando 13-19 de 19 artigos, teses e dissertações.
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13. Avaliação dos modelos de predição de propagação para telefonia móvel celular na cidade do Natal
The development of wireless telecommunication in the last years has been great. It has been taking academics to conceive new ideas and techniques. Their aims are to increase the capacity and the quality of the systems services. Cells that are smaller every time, frequencies that are every time higher and environments that get more and more complex, all those
Publicado em: 2006
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14. Externalidade de rede e a telefonia fixa-móvel: um estudo sobre o poder de mercado da telefonia móvel e a demanda por serviços de telecomunicações
This piece of work develops a theoretical model of the fixed-mobile telephony market, trying to analyze the characteristic of consumers externality (network externality) existent in the network industries, as well as the specific phenomenon of bottleneck in that market, in which the cellulars firms have certain domain over their costumers. This market power
Publicado em: 2005
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15. Selection algorithm of spreading sequences for CDMA systems with space-time coding and antenna array / Algoritmo de escolha de sequencias de espalhamento em sistemas CDMA com codificação espaço-temporal e arranjo de antenas
The performance of mobile communication systems based on the CDMA technique is limited by interference. In this thesis, we propose a selection algorithm of spreading sequences with fixed length for interference mitigation on CDMA systems over frequency-selective fading channels, that is based on the minimization of the overall mean bit error probability of t
Publicado em: 2005
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16. Efeitos de acoplamento e de banda de operação em redes de antenas adaptativas reais. / Coupling and operation bandwidth effects in real adaptive antenna arrays.
Smart antenna arrays are becoming more important in the expansion and in the enhancement of cellular telephony systems, specially in the third-generation that will need an even larger bandwidth. In this subject, many contributions from the scientific community have been provided with the goal of determining direction-of-arrival for incident signals, eliminat
Publicado em: 2005
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17. Performance analysis of 2G, 2.5G and 3G cellular mobile systems / Analise de desempenho dos sistemas moveis celulares 2G, 2,5G e 3G
Este trabalho de tese estuda e analisa o desempenho dos sistemas móveis celulares GSM de segunda geração (2G), GPRS de segunda geração intermediária (2,5G) e CDMA2000 de terceira geração (3G). Na primeira parte deste trabalho de tese são avaliadas estratégias de compartilhamento dos canais de comunicação utilizados pelos sistemas GSM e GPRS, em b
Publicado em: 2005
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18. Electromagnetic interference in the band of cellular mobile telephony / InterferÃncia eletromagnÃtica na faixa de telefonia mÃvel celular
Este trabalho à o resultado de uma pesquisa de campo realizada na cidade de Manaus/AM, cujo objetivo principal à avaliar o nÃvel de concentraÃÃo da potÃncia dos sinais dos serviÃos de radiodifusÃo e dos serviÃos de telefonia mÃvel que ocorrem em determinadas Ãreas da cidade e incidem sobre o cidadÃo que por ali reside ou transita. Com os resultad
Publicado em: 2004
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19. UM FRAMEWORK PARA PROVISÃO DE QOS EM REDES MÓVEIS SEM FIO / A FRAMEWORK FOR QOS PROVISIONING IN WIRELESS MOBILE NETWORKS
In the last decades, increasing interest has been observed in technologies related to wireless mobile communication environments. Great part of such interest follows the growth in the telecommunications industry, more specifically of cellular mobile telephony systems. Users are quickly absorbing these technologies and generating new necessities, such as the
Publicado em: 2002