Adaptive Space-Time Processing Technology For CDMA Mobile Communication Systems

The Smart Antenna System, has been the present focuses in signal processing and communication field, which smart multi-beam antenna is formed by means of antenna array embedded by signal process technology. And The Smart Antenna has also been one of the key technologies of the Third Generation Mobile Communication Systems. Optimum beamforming in receiving and transmitting mode and adaptive signal process can be formed by means of the Smart Antenna Technology in wireless communication, then base antenna coverage, system capacity and service quality are improved, also inter-symbol interfere. multi-access interfere and transmitting power are reduced. In addition, co-channel interferes and Near-far problem is well jammed due to the Smart Antenna. In this dissertation, space- time 2 D RAKE receiver version and algorithm related multi-path parameter estimation, adaptive beamforming in receiving and transmitting mode, and space-time multi-user detection in COMA communication systems are studied. The main contributions of the dissertation are as follows: 1. Based on broadband antenna array, a new blind ST-DRCMA algorithm is presented which combats both MAI and ICI for OS/COMA systems. The algorithm proposed utilize the constant modulus properties of CDAM signals and spread signature known. Also no despreading and channel parameter estimation is needed on the output of delay taps. and computation complexity is low. Computer simulation is illustrated the performance of ST- DRCMA receiver. 2. Space time 20 RAKE receiver is applied in the Third Generation Mobile Communication Systems. In other words, space time 2D RAKE receiver is realized in W- CDMA condition. Due to the aid pilot frequency in reverse link, channel parameter estimation can be implemented in W-CDMA systems. And two kinds of cascade structure 2D RAKE receiver method are presented, also the performance of space time 2D RAKE receiver is analyzed. 3. On single path condition, the multi-user detection algorithm is derived on the basis of?minimal mean square rule and ML rule. The relation of single user detection and multi- user detection is also analyzed. Also a space time multi-user detection structure and an adaptive method on CDMA systems is proposed. The performance of the algorithms proposed is much better than that of traditional single-user detection. 4. Using minimal mean square rule and ML rule on condition of asynchronous multi-path derives CDMA multi-user detection algorithm. The relation of single user detection and space-time multi- user detection is also analyzed. Also a space time multi-user detection structure is proposed. In the meantime, an improvement about the SAGE algorithm is proceeded on the basis of finite alphabet characteristic and pilot information of COMA. 5. Combined with smart antenna, a space-time interference cancellation CDMA multi-user detection is proposed by utilizing successive interference cancellation method. And a new interference successive cancellation algorithm is derived, which combined with space-time RAKE receiver. Computer simulations illustrated that the performance of the algorithms proposed is much better than that of traditional single-user detection. 6. Standing on the fact that bi-directional commonalty holds between up-link and downlink Channel State in COMA mobile communication, downlink signal Sub-space State is defined by up-link signal sub-space decomposition. Then downlink beam-forming weights are generated. This method proposed requires...