Research On Technologies Of Multi-user Detection In Third Generation

The chief work of the paper is to discuss the subspace approach for multi-user detection technology deeply, and to carry on the simulation analysis to its function, based on analyzing several kinds of representative linear multi-user detections. It contains four parts:1.Briefly looks back the development of the third generation of mobile communication technology, and analyses merit and shortcoming of CDMA system which as nuclear technology of 3G On the foundation of discussion ,we explain the necessary which bring to bear multi-user detection.2. On the foundation of analyzing mobile communication channel characteristic, we import channel model that this article uses, and analyze discrete system model and reach its matrix form aiming at the digital communication system. At the same time, we illation the synchronous and asynchronous DS-CDMA system model, analyze the principium of conventional one user receiver, matched filter receiver and Rake's receiver, and point out that conventional one user receiver can not eliminate multi-address interference.3. On the foundation of analyzing CDMA system interference, we expatiate the principium and model of multi-user detection, probe into several kinds of representative linear multi-user detections. At the same time, we also study DEC and MMSE multi-user detection thorough, analyze the linear multi-user detection's mistake bit rate and far - near effect. The simulation result indicates that multi-user detection can restrain MUI, and resist far - near effect.4. Educe the concept of subspace approach for multi-user detection, give out the subspace expression about DEC and MMSE multi-user detection. At the same time we simulate the capability of DEC and MMSE multi-user detection with the high SNR, the result indicates that they have the same ability in restraining MUI and resisting far - near effect. We also study the arithmetic of subspace approach for multi-user detection that was put forward by Xiaodong Wang.for multi-user detection that was put forward by Xiaodong Wang.