Mobile Communications
Mostrando 13-24 de 47 artigos, teses e dissertações.
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13. Gerenciamento do espectro de freqüências, otimização e compartilhamento de rede móvel em múltiplas tecnologias
Since the emergence of mobile communications, operators and suppliers constantly seek new technologies and services to fit the needs marketing. This paper presents the development of mobile telephony up to today, highlighting the challenges faced by technical and commercial operators. The main goal is to show and highlight the management of spectrum for the
Publicado em: 2008
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14. Adoção de tecnologias móveis em empresas do Rio Grande do Norte, Pernambuco e Ceará
One of the best examples of the Information and Communication Technology (ICT) evolutions is on the high capability of storing and processing data into smaller devices, creating a new business condition, the mobility. This mobility in a deeper analysis proposes a business remodeling in many different areas (business segmentations), through the Internet anywh
Publicado em: 2008
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15. Innovation development of core competences and diversification of communication market : the use of the internet in two groups of Brazilian press media / Inovação, formação de competencias e diversificação no setor de comunicação : a exploração da internet em dois grupos brasileiros de midia impressa
The emergence of the internet as a new medium obliged the companies in the printed media to define strategies for entering the communications and services market based on this platform. The proposed study presents the results of research into strategies of business diversification in Brazilian printed communications companies, based on the exploitation of se
Publicado em: 2008
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16. A PPCCIPS- A política pública da coleta complementar, itinerante e programada de sangue-sob a luz da teoria do ciclo da política Pública.
This study aimed to focus on aspects of public administration concerning the implementation of the public policy of complementary blood collection by the itinerant and scheduled PPCCIPS services either trough off local unity or mobile unit blood collection operations, which are managed by the State Institute of Hematology Arthur de Siqueira Cavalcanti -
Publicado em: 2008
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17. Aplicações de antenas adaptativas em sistemas de comunicações móveis / Applications of adaptive antennas in wireless communications systems
The increasing demand for wireless communications services has demanded the development of technologies that allow serving a bigger amount of users without increasing the bandwidth used today. It also has an increasing demand for services that need high transmission rates on mobile terminal, as Internet and video transfer. On the other hand, the user desires
Publicado em: 2007
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18. Distribuição de weibull na emulação de canal em redes WLAN para avaliação de VoIP / Weibull distribution in WLAN channel emulation for VoIP evaluation
O trabalho investiga de forma quantitativa e qualitativa o desempenho de VoIP (Voz sobre IP) em uma rede WLAN (Wireless Local Área Network), denominado WVoIP, (Wireless VoIP) considerando degradação em ambiente indoor. Para atingir esse objetivo foram realizados testes utilizando um emulador de canal capaz de produzir fenômenos de propagação com distri
Publicado em: 2007
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19. Methodology for calculation of spectrum requirements estimation for the future development of cell mobile system / Metodologia de cálculo de espectro para suportar a evolução do sistema móvel celular
This work presents a methodology for calculation of spectrum requirement estimation for future development of 3G and beyond-3G systems based on ITU-R recommendations. It presents a systematic approach that incorporates service category definitions, service environments, radio environments, market data analysis and traffic estimation for these categories and
Publicado em: 2007
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20. Sobre equalizadores autodidatas de decisão realimentada aplicados a sistemas multiusuário
Due to the growing demand for mobile communications, adaptive equalizers play an important role for enhancing the efficiency of data transmission. In this scenario, the Decision Feedback Equalizer (DFE) stands out. It presents a favorable tradeoff between computational cost and efficient behavior, mainly when compared to Linear Transversal Equalizer. In this
Publicado em: 2007
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21. Analise comparativa entre protocolos de camada MAC para redes ad-hoc sem fio / Comparative analysis between MAC-level protocols for ad-hoc wireless networks
Este trabalho visa o estudo de redes ad hoc sem fio, em especial, os protocolos da subcamada MAC do modelo OSI. Neste tipo de rede sem controle centralizado, o acesso ao meio se torna uma parte crítica no processo de comunicação entre terminais. Assim sendo, a principal motivação deste trabalho é investigar como os protocolos da subcamada MAC podem afe
Publicado em: 2007
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22. Simulador para servidor habilitador de localizaÃÃo em plataforma LBS
Since XIX centuryâs end, the telephony suffered to constant technological evolution. In the 70âs, a new need was looked for: mobility. So, it began the age of the mobile communications. The increasing integration between cellular systems and computer science made possible the development of new technologies and services to the mobile networks. Currently, t
Publicado em: 2006
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23. Proposta de um esquema de codificaÃÃo de vÃdeo a baixas taxas de transmissÃo para comunicaÃÃes mÃveis celulares / Proposal for low bit rate video coding for cellular phones communications
Very low bit rate coding below 64 kbit/s will be an important issue in forthcoming visual services such as videophone and multimedia systems. The trend of increasing interest in, and demand for, mobile phone, interactive TV and multimedia services, has led to significant acceleration of video coding research worldwide. This paper introduces and presents simu
Publicado em: 2006
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24. Analysis of optical CDMA systems / Análise de sistemas CDMA ópticos
The evolution of optical networks verified in the last few years has been characterized by the search for better bandwidth utilization efficiency. The successful implementation of practical code division for multiple access techniques (CDMA) in mobile communications systems has stimulated new investigations on this topic, particularly in the optical domain (
Publicado em: 2006