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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

Técnicas de compartilhamento de espectro baseadas em teoria dos jogos para acesso local em sistemas IMT-Advanced

Costa, Gustavo Wagner Oliveira da 10 July 2008 (has links)
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2008. / Submitted by Jaqueline Oliveira (jaqueoliveiram@gmail.com) on 2008-12-01T16:15:28Z No. of bitstreams: 1 DISSERTACAO_2008_GustavoWOdaCosta.pdf: 1977514 bytes, checksum: 8e6a4620478a65759340b79ffbce0be8 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-11T17:50:32Z (GMT) No. of bitstreams: 1 DISSERTACAO_2008_GustavoWOdaCosta.pdf: 1977514 bytes, checksum: 8e6a4620478a65759340b79ffbce0be8 (MD5) / Made available in DSpace on 2009-02-11T17:50:32Z (GMT). No. of bitstreams: 1 DISSERTACAO_2008_GustavoWOdaCosta.pdf: 1977514 bytes, checksum: 8e6a4620478a65759340b79ffbce0be8 (MD5) / Teoria dos jogos / A banda necessária para o provimento de serviços no acesso local será muito maior do que as utilizadas em sistemas 2G ou 3G, chegando a cerca de 100 MHz. Por causa disto, estes sistemas terão que trabalhar com espectro sem paridade e compartilhando um conjunto comum de recursos de espectro que será licenciado mas compartilhado entre operadoras. Neste trabalho é proposta uma solução inovadora, baseada em teoria dos jogos, que trata dos principais problemas em tal cenário: latência na alocação inicial de espectro, configuração autônoma, eficiência espectral e justiça na distribuição dos recursos. O protocolo proposto é dividido em duas partes para satisfazer todos estes requisitos, que são conflitantes. Os resultados obtidos mostram que o algoritmo proposto é capaz de prover eficiência espectral bem maior do que os casos mais simples de alocação fixa de espectro. No cenário estudado, o algoritmo proposto aproxima a eficiência espectral do planejamento de freqüências ótimo, sendo ao mesmo tempo capaz de redistribuir a capacidade de acordo com o tráfego e o número de estações rádio base ativas. ______________________________________________________________________________________ ABSTRACT / The required bandwidth for the envisioned services in IMT-Advanced local access is much larger than those usually allocated to 2G and 3G services, in the order of 100 MHz. For that reason, it is envisioned that such systems will have to work in an unpaired spectrum environment where the whole spectrum pool is licensed but shared amongst operators. A novel approach based on Game Theory is proposed, dealing with some of the main issues in such a scenario: latency for initial spectrum assignment, self organization, spectrum efficiency and fairness. In order to meet all those requirements, the proposed protocol has two special states. In the new entrant state the protocol makes an efficient initial spectrum assignment aiming at reduced latency. In the second protocol state, the game is repeated to track load variations, provide long term fairness and enhance the spectrum efficiency. The results show that the proposed framework is capable of providing spectrum efficiency considerably higher than simple approaches for uncoordinated deployment, such as full reuse or having separate spectrum pools. In fact, in the studied scenario, our approach approximates the spectral efficiency of the optimal spectrum planning for full load while tracking traffic variations and self adapting for the number of active base stations.
2

Policy-Based Flexible Spectrum Usage for Next-Generation Mobile Communication Networks / Policy-Based Flexible Spectrum Usage for Next-Generation Mobile Communication Networks

Musil, Tomáš January 2010 (has links)
This Master's thesis deals with proposal of Flexible Spectrum Usage (FSU) algorithm based on policy agreed among operators. The introduction presents basic information about properties of next generation mobile communication ITM-Advanced system. After the introductory part the attention is given to the items efficient for FSU implementation as well as parameters used for evaluation of FSU algorithm efficiency. Several variants policy based FSU algorithm utilize value of Signal to Interference plus Noise Ratio (SINR) is designed. The SINR information is used to combat with mutual interference which is caused by coexistence of several operators in the same geographical area sharing over the same spectrum pool. Individual needed as traffic and quality of service requirements of each operator is taken into consideration as well. The main aim is to maximize cell troughput as well as data- rates for each user of HBS. For simulation of proposal algorithm is considered deployment of four Currently Home Base Stations (HBS) in indoor loacal area scenerio with random number of users in given range. Each operator makes independent dicision without signalling exchange among other. The only considered information that HBS can use is gotten by scenning its environment. This problem soliving is considered to use Cognitive Radio (CR)
3

Policy-Based Flexible Spectrum Usage for Next-Generation Mobile Communication Networks / Policy-Based Flexible Spectrum Usage for Next-Generation Mobile Communication Networks

Musil, Tomáš January 2010 (has links)
This Master's thesis deals with proposal of Flexible Spectrum Usage (FSU) algorithm based on policy agreed among operators. The introduction presents basic information about properties of next generation mobile communication ITM-Advanced system. After the introductory part the attention is given to the items efficient for FSU implementation as well as parameters used for evaluation of FSU algorithm efficiency. Several variants policy based FSU algorithm utilize value of Signal to Interference plus Noise Ratio (SINR) is designed. The SINR information is used to combat with mutual interference which is caused by coexistence of several operators in the same geographical area sharing over the same spectrum pool. Individual needed as traffic and quality of service requirements of each operator is taken into consideration as well. The main aim is to maximize cell troughput as well as data- rates for each user of HBS. For simulation of proposal algorithm is considered deployment of four Currently Home Base Stations (HBS) in indoor loacal area scenerio with random number of users in given range. Each operator makes independent dicision without signalling exchange among other. The only considered information that HBS can use is gotten by scenning its environment. This problem soliving is considered to use Cognitive Radio (CR)
4

Základy mobilního internetu / Mobile internet principles

Jehličková, Lenka January 2011 (has links)
Thesis concerns with mobile communications theory with focus on data transfer. In the introduction the history, the origin and individual mobile systems generations are described. It is followed by detailed description of second, third and fourth generation mobile systems. Frequency band allocation, signal processing, the system architecture itself, security management and basic features are also discussed. The GSM system is described together with individual data transmission types based on circuit switching – CSD and HSCSD and packet switching – GPRS and EDGE. For UMTS, FDD and TDD modes are listed as well as changes in individual releases, corresponding technologies and provided services. Next, there is the description of LTE and WiMAX systems, together with their improvements whose are part of the fourth generation of mobile systems. Last of the described systems is the still work in progress HAPS, also known as the system of stratospheric platforms. In the end important parameters are summarized and systems are compared with each other.

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