The Implementation Study Of Smartantenna In TD-SCDMA System

Smart antenna (SA) technology is one of the key technologies of TD-SCDMA (TD). The performance of anti-interference, system capacity, electromagnetic environmental pollution and spectrum efficiency could be effectively improved by using SA in TD system. So, there is great value for the research of the SA technology in TD system.Beam forming and the direction of access (DOA) estimation technique are the core technologies of SA application. This article briefly introduces the existing research results of beam forming and DOA estimation, and compares the performances of those different beam forming algorithms and DOA estimation algorithms through the analysis and simulation. Considering the application situation of the existing beam forming and DOA estimation algorithm in the TD system, this article puts forward an easy algorithm of DOA estimation in TD system by using the features of mid-sequence and the model of TD SA receiving system. On the basis of new DOA estimation algorithm, a simple implementation scheme of SA in TD system is presented. In this scheme, one method named MBF is put forward to get the parameter of array manifold from the receiving system directly, the method is simple and easy to be implemented, and the number of DOA estimation that can be detected is unrelated with the number of antenna elements in the receiving systems. Also, the difficulty of the beam forming could be reduced.Finally, the simulation results of spectral search algorithm using the weighting method of base-band amplitude and carrier phase-shifting are given in the paper, and the feasibility of MBF method could be proved by the simulation. The problem is that the method has not been verified by the real electric circuit, so it is needed to research that method further.