| The mobile communication system of FDMA, TDMA or CDMA is going to get to it's capacity margin and is difficult to meet demand in system capacity, voice quality and kind of service with rapidly development of mobile communication and speedy increase of quantity of mobile communication consumer. How to improve the utilization of wireless resourse is highlighted. Going with the development of array signal processing, SDMA technology can remarkably improve the performance of mobile communication system. Application of SDMA technology in mobile communication system has attracted attention.By adopting SDMA, consumers of mobile communication system is served with diffirent directed beam. The power radiated by Base Station and Mobile Station is controlled and directed into Mobile Station. SDMA technology has execllent advantage in enhancing system capacity and increasing the utilization of wireless resource and improving system dependability and reducing system cost.SDMA technology comes from radar and sonar. It is not applied to mobile communication because of high cost and other factor. With rapid development of micro-electronics and progress of digital signal processing technonoly, SDMA technology is stepping in public communication. SDMA will have a good prospect in mobile communication thanks to advanced digital signal processing technology. Since 1990's, SDMA is proposed after space array signals processing technology introduced into mobile communication field. This technology is researched in a lot of famous university, scientific institution, telecom company and telecom working campany. SDMA has exclusive advantage on imprpve communication quality and make tradeoff on increasingly growth of telecom and wireless frequency resource and reduce system cost and improve telecom system administration. Many countries recognize the effect of SDMA on future mobile communication system and propose a lot of academic research on SDMA. At the same time, they established experiments. Many communication companies and universities and graduate school have developed experimental system to work over SDMA integrated with mobile communication system. With the rapid progress of DSP and FPGA technology and digital signal processing, SDMA will get hold of ulterior developing.Although the performance of SDMA technology is attractive, it has many difficults in applying SDMA into mobile communication system to this day. In this dissertation, on the basis of research of SDMA technology the author proposes several ways to deal with these problems. The main contributions include: research for multiple DBF and system capacity improvement by applying SDMA technology; the effect of array antennas channel error on DOA algotithm and calibration for array antennas channel error; grouping usering signal and multipath signal and their DOA estimation.Two DBF algorithm( directly adding main beam offset algorithm and LMS algorithm) is analysed at length. The effect on mobile communication system performance by applying these two DBF algorithm is given in this dissertation.The effect of array antenna channel error on DOA algorithm and analysis of some array antenna channel error calibration motheds is given. Based on analysis of existing calibration algorithm, we propose a blind calibration mothed for array antenna channel error which need a signal station for calibration. Because azimuth of signal station is not need, there is not any relation between the performance of this algorithm and the precision of DOA measure of signal station.We not only analyse performance of MUSIC algorithm and 1-D noise subspace algorithm but also investigate the effect of multipath on these two algorithms. Existing algorithm such as space smooth can not resolve a problem that which user does a multipath signal derive from though this algorithm can deal with correlation. To resolve this problem we propose an algorithm which first group user signals and multipath signals then estimate the DOA of user signals and multipath signals.
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