Research Of The Downlink Performance And Capacity For Distributed Antenna System MIMO In Multi-Cell Environment

The main challenge of the future wireless system is the conflicting of the scarce frequency resources and requirement of the various high-speed data services. To meet the demand of the high data rate multimedia services and the quality of service (QoS), a higher bandwidth and frequency efficiency is needed, which is stimulating the research on the new wireless transmission technologies and network infrastructure. Currently, the great capacity advantages of the multiple input multiple output (MIMO) system result in the research on the space-time processing technologies. The distributed antenna system, which is an innovative structure compared with the traditional cellular one for its natural advantages in coverage, frequency efficiency, transmit power etc, become a hot research topic. The thesis focuses on the key technologies of distributed antenna system. The research topics cover the antenna selection algorithms in distributed MIMO system, the transmit diversity technology of distributed antenna system, etc.We give an overview of current state of the mobile communication in chapter 1, emphasizing MIMO and relative techniques. The DAS-MIMO system model is setup and the research background of this thesis is discussed in chapter 2. In chapter 3, the basic principle of space-time diversity in MIMO system is described first, while the detail discussion of receive diversity in DAS-MIMO as a follow. A novel distance information precondition (DIP) arithmetic is employed to optimize the system performance. Simulation shows that DIP can efficiency reduces the requirement of system calculate precision comparing with conventional zero-force detection. The single user downlink performance and capacity of DAS-MIMO in multi-cell environment is discussed in chapter 4. Virtual cell DAS (VC-DAS) is introduced to optimize the on boundary SINR, system BER and power efficiency performance. The system capacity with maximum ratio combining (MRC) both in channel-state-known-to-transmitter (CSIT) and channel-state-known-to-receiver (CSIR) are enhanced under VC-DAS. The parameters such as: environment factors, modulation modes, number of selection antennas etc. are particular discussed. Finally chapter 5 is presented as an inclusion of the work, and a further research propose is schemed.