Título:	Emprego de antenas adaptativas para a estimação de dados em ambiente CDMA
Outros títulos:	Applying adaptive antennas for data estimation in CDMA medium
Autor(es):	Puttini, Saulo Benigno
Orientador(es):	Zelenovsky, Ricardo
Assunto:	Antenas (Eletrônica) Múltiplo acesso por divisão de código Algoritimos adaptativos Sistema CDMA Engenharia elétrica
Data de publicação:	20-Jan-2010
Data de defesa:	2006
Referência:	PUTTINI, Saulo Benigno. Emprego de antenas adaptativas para a estimação de dados em ambiente CDMA. 2006. 102 f. Dissertação (Mestrado em Engenharia Elétrica)-Universidade de Brasília, Brasília, 2006.
Abstract:	This work founds in proposing and evaluating the performance of an adaptive receptor model, applying array of sensors, for use in code division multiple access (CDMA) mediums for data estimation. First, a basic study about antenna arrays is presented, followed by the development of the algebraic equations of the linear uniform array (ULA). It is emphasized the use of these arrays for spatial separation, along with some considerations and illustrations of beamforming techniques. Moving forward, the thesis approaches the employment of adaptive algorithms, especially the Wiener and Least Mean Square (LMS) filters, in array of sensors, resulting in the widely known adaptive arrays. Next, the problem of direction of arrival (DOA) estimation is attended, with several well recognized methods being displayed. Some simulations of power spatial spectrum are made, aiming to evaluate, mainly, the resolution ability and the noise immunity. Thus, a methodology applying adaptive algorithms for DOA estimation with array of sensors is signalized as a secondary result. The spread spectrum technique, along with its features and peculiarities, is showed on the continuity, emphasizing the use of the Direct Sequence Spread Spectrum (DSSS) for CDMA mediums. Under this context, the synchronization problem is raised and treated, culminating in the presentation of an algorithm, based on temporal correlation, for delay detection. This algorithm was applied in the proposed receptor model. Finally, a CDMA adaptive receptor model is proposed, exhibited and tested under different conditions of noise, interference, power control and number of sensors. Special treatment is dedicated to the tracking of mobile users, where it is witnessed the aptness of the model in adapting its radiation pattern for dynamic situations. Through the simulations, it is showed that the receptor model is able to spatially separate the sources, recover the original signal and track the mobile users, having as sole previous information the code sequence of the sources itself. The attained results are pretty satisfactory. The model came up to be highly immune to medium noise and considerably robust to co-channel interference.
Unidade Acadêmica:	Faculdade de Tecnologia (FT) Departamento de Engenharia Elétrica (FT ENE)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2006.
Programa de pós-graduação:	Programa de Pós-Graduação em Engenharia Elétrica
DOI:	http://dx.doi.org/10.26512/2006.D.3361
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

Os itens no repositório estão protegidos por copyright, com todos os direitos reservados, salvo quando é indicado o contrário.