Estimação da direção de chegada (DOA) de sinais eletromagnéticos em canais reversos CDMA utilizando antenas inteligentes

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The great effort of communications engineers is to create methods that allows improve spectrum usage efficiency, that is a scarce resource. The Code Division Multiple Access (CDMA) and the spatial processing techniques using array of antennas are two enable technologies to achieve this task. In this context, the smart antennas technique can improve the reception of the signals of interest and can reduce the interferences at the same time. For this reason, it is important the estimation of the Direction of Arrival (DOA) of the signals of interest. In this dissertation, initially, the technology of smart antennas and the cellular CDMA system are described. Then, several Direction of Arrival estimation techniques of electromagnetic signals using the reverse channels CDMA are studied and compared. After that, three Direction of Arrival estimators are presented and their performances are compared for estimative absolute mean error and estimative variance error. These methods use the maximum likelihood (ML) approach with expectation maximization (EM) algorithm and are called EM1, EMM and EMS. It is verified, using simulations in MATLAB, the EMM algorithm has excellent performance in all created scenarios. In conclusion, the EMM algorithm using in reverse channel CDMA presents better results.

ASSUNTO(S)

cdma engenharia eletrica processamento de sinais algoritmo expectation maximization (em) estimadores de direção de chegada (doa) antenas inteligentes

ACESSO AO ARTIGO

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