Study Of DOA Estimation With Non-Uniform Smart Antenna

Smart antenna technology can adjust the beam former according to the direction of user's signal. Therefore, smart antenna can reject the interferences, increase the system capacity, decrease the transmitting power and many other advantages. The parameter of DOA (Direction of Arrival) plays a very important role in smart antenna system. It is affected whether the system can adjust coefficients correctly and whether the main lobe can point at the user direction by the DOA information. However, lots of effective methods are put forward under the condition of uniform linear antenna array (ULA). The space of ULA is always less than or equal to half wavelength of the transmit signal. Thus the number of antenna elements limits the aperture. In this paper, DOA is estimated with non-uniform linear antenna array (NULA) instead of ULA, so as to achieve a much larger aperture with the same amount of antenna elements.Several classical estimation algorithms are adjusted to meet the requirements of estimating DOA with the NULA, including beam forming, MUSIC, and Capon minimum variance algorithm. In addition, the differences of the three algorithms are compared, and the one that better suits the NULA is achieved. On the basis of the above research results, the advantages and disadvantages of NULA are analyzed; and the resolving power, resolving precision and resistance from the noise interference with ULA are also compared.There put forward three methods to promote the estimation performance of NULA. The three methods are based on different points of...