Mimo Systems Based On Limited Feedback Multi-user Scheduling

Multiple Input Multiple Output (MIMO) technique is an important method to provide high speed data rate transmission and enhance the quality of data transmission in future wireless communication systems. Most research about MIMO is related to single user system, however, in many real situations, the base station has to serve multiple users simultaneously. In such a multiuser MIMO system, there exists multiuser diversity, which can be used to exploit the multiuser diversity gain to improve the whole system performance. Besides, in order to eliminate the Co-Channel Interference (CCI) among multiple users, the transmitter has to exploit the Channel State Information (CSI) of users to pre-proceed the transmitted signal.On the basis of the two above aspects, our researches focus on the closed loop multi-antenna multi-user system. Since the perfect CSI is not easy to get at the base station, we also analyze the limited feedback for designing beamforming and scheduling methods. The main contents are as follows:1. Analyze the capacity performance improvement using MIMO technique in single user systems.2. Depict the limited feedback uplink model in multi-user MIMO system, introduce and compare several typical beamforming techniques, furthermore, analyze the impact on the system performance induced by limited rate feedback.3. Summarize the rules of designing multi-user scheduler, and research typical scheduling algorithms. Propose a modified Semi-orthogonal User Selection (SUS) technique for systems with a large number of users.4. Base on the newly definition of Signal-Leakage and Noise Ratio (SLNR), the thesis propose two scheduling methods, and analyze the system performance of the proposed algorithms, then compare the sum rate and complexity performance with different channel quality indicator (CQI).