Research On Multiuser MIMO Precoding And User Scheduling Algorithms

As more and more internet and mutil-media applications blend into the internet. The number of mobile users is increasing. It requires next-generation mobile communication system can provide users with the faster data transmission and better quality of service. The development of Multi-user MIMO (Multiple Input Multiple Output, MIMO) technology make enables to continuously meet the needs of users as possible. Compared with single-user MIMO technology, Multi-user MIMO(MU-MIMO) technology is not only provide multiplexing gain,but also bring multi-user gain. But a series of problems attendant,such as co-channel interference (CCI) issues and user overload issues. Precoding technology can solve the co-channel interference problem, THP precoding is one of effective precoding method to eliminate the co-channel interference. User scheduling technology can solve the user overload effectively. So in this paper,we make a deep research in the THP precoding technology and the user scheduling technology of the multi-user MIMO system under the ideal channel.First,several classic precoding algorithms,including linear precoding such as,ZF,MMSE precoding and BD precoding and nonlinear THP precoding are researched deeply.MMSE-THP based on extended matrix precoding algorithm is presented detail.Compared with channel matrix inverse MMSE-THP precoding algorithm, the algorithm not only can get the same performance, but can reduce the computational complexity.Secondly,the paper also designed an architecture model of multi-patterns THP. Designing multiple alternative transmission pattern at the transmitter, select the most suitable transmission pattern to transmit single by minimize error selection criteria. On the basis of the structure model, combined with MMSE-THP based on extended matrix precoding algorithm proposed multi-patterns MMSE-THP based on extended matrix precoding algorithm. With the number of alternative branch increased, the algorithm's BER performance will be better and better, But the complexity of the system can also become larger. So in order to be able to compromise on performance and complexity, need to select the appropriate number of transmission patterns. Simulation results show that compared with other similar algorithms,the algorithm can improve BER performance of the system well.Finally the paper proposes THP precoding user scheduling based on the minimum bit error rate algorithm, By using this algorithm can improve the BER performance of the communication system. And make the algorithms united with the multi-patterns THP structure.The simulation results show that the joint optimization algorithm has better performance than the THP precoding user scheduling based on the minimum bit error rate algorithm.