| In smart antenna systems, digital signal process technologies are used to produce spatial and directional beam to aim the main beam at the coming direction of user signal of interest with the side lobe aiming at the coming direction of signal of interference user so that the signals of the user of interest are made use of with great efficiency while the interference signals are eliminated or restrained. Smart antennas are divided into two categories: switching-beam antennas and adaptive-beam antennas. Smart antenna technology has been confirmed as one of key technologies of the third generation mobile communication system, and will play an important role in the future communication systems.In this paper, the DOA algorithms of smart antenna are researched. First, the development of smart antenna and mobile communication is reviewed and the principles of the DOA smart antenna are generalized. Secondly, traditional DOA algorithm is introduced, which mainly includes the defer-addition algorithm and the capon algorithm, and their theoretical performance is deeply analyzed. Finally, subspace decomposition algorithm is primary studied, namely the MUSIC algorithm and the ESPRIT algorithm, which mainly include the classical MUSIC algorithm, the space smoothing MUSIC algorithm, the basic ESPRIT algorithm and the you-ESPRIT algorithm. For the MUSIC algorithm, this paper focuses on a MUSIC smoothing algorithm based on the coherent solution and on this foundation, some improvements are made. The improved algorithm can reduce the computation time and its estimation performance is superior to the classical algorithm. For the ESPRIT algorithm, some improvements are also made by the utilization of the space smoothing technology based on the basic algorithm. The performance of the improved algorithm is enhanced which can be favored by the simulation results. |
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