Smart Antenna DOA Technology Of Mobile Communication

The Smart antenna is one of the key technology in the third generation(3G) system. And it has been the present focuses in signal processing field. It combines the antenna array technology with the signal processing in space and time . The spatial processing leads to more degrees of freedom in the system, improves its overall performance, and enhances the system capacity and spectrum efficiency. The Smart antenna, which is adopted in the wireless mobile communication system, in fact, forms an antenna with a high gain. Thus communication in all directions can be proceeded, then base station antenna coverage, system capacity and service quality are improved, also inter-symbol interferes and mufti-access interfere are reduced. The space division multiple access(SDMA) is introduced, and users can be distinct from each other through their special location. So the DOA of users plays a very important role in smart antenna systems.Smart Antenna has two critical tasks,one is to filter the uplink signals,and the other is to form the downlink beam, and we need adaptive algorithm and digital signal processing(DSP) technology to fulfill these work .Adaptive algorithm is one of the most important technology of Smart Antenna, and it determines Smart antenna's respondent speed to the wanted signal and the complexity of the circuit of the communication system. Consequently, the system should select reasonable algorithms in various communication environment, and algorithm diversity technology could optimize the system to work well.In this paper, we compare some algorithms. Then, An iterative algorithm for signal subspace estimation based on sparse PCA(sparse principal component analysis) is proposed. The algorithm contains only relatively simple operations and has self organizing properties. Simulations show that the proposed algorithm has an analogy performance with MUSIC algorithm.