Study On Key Technologies Based On Digital Beamforming In Smart Antenna

As the key technique of the third generation mobile communication,smart antenna has got broad attentions in recent years.Smart antenna provides an efficient approach to solve frequency resource deficiency, to improve the capacity and quality of mobile communication systems,and achieve anti-jamming and antimultipath.The direction of arrival(DOA)estimation is an important aspect in the smart antenna research.Having read a lot of transactions in the area of interest, the author aims at the subject on direction of arrival technology of smart antenna technology and makes efforts to study the problems below:â‘ The theory of smart antenna is introduced, the basic model of array antenna and the statistical model of array signal processing and the mathematical model of coherent signals are analyzed, the relation of the direction of arrival and digital beamforming is illuminated;â‘¡Traditional DOA estimation algorithms are summarized, the MUSIC algorithm based on the subspace is analyzed, and the estimate performance of those algorithms are further researched and analyzed through the simulation. In addition, number of signals estimation theory, which is the foundation and key of direction of arrival estimation, is also researched and simulated;â‘¢Theory and character of singular value decomposition are introduced, subspace fitting algorithm and its fast realizable algorithm MVP(Modified Variable Projection), spatial smoothing method of coherent signals and the algorithm of number of signals estimation are studied.And then, the SVD is used in the above algorithms to analyze and simulate.â‘£Theory of four-channels analog signal generator is introduced and simulated.The four-way analog signal generator is completed and tested in practice,then its circuit is described in detail.