Research On The Capacity And Channel Estimation For MIMO System

The recent research on information theory indicates that, MIMO technology can increase the capacity of wireless communication remarkably. It's extremely suitable for the next generation radio communication system. In the past, most research on MIMO has made the assumption that channel between antenna pairs is independent. However, in the actual wireless transmission environment, correlation usually exists in MIMO channel. In this thesis, the effect of correlation on MIMO systems is researched. To develop a MIMO system, exact channel estimation is necessary. MIMO channel estimation is more complex than SISO channel, which leads to the complexity of the receiver.Firstly, this thesis analyzes channel characteristic in MIMO system, studies the effect of two important parameters—antenna separation and angle spread in correlation channel on the channel transmission matrix, and presents three correlation models of MIMO fading channel. Secondly, the average capacity of several typical systems, such as SISO, MISO, SIMO, MIMO, is theoretically analyzed and simulated, and the relationship between the capacity and different schemes for power distributing is discussed. Thirdly, MIMO channel estimation algorithm based on pilot symbol assistance in the case of flat fading channel is researched, some simulation results are presented, and the performance of several typical methods is analyzed. The results of simulation show that enhancing the pilot data ratio in a frame can improve the performance of channel estimation algorithm. In the end, a MIMO system simulation platform is designed, and bases on this platform, the effect of correlated fading and channel estimation on the MIMO system is researched. The results of simulation show that,with the platform, each main module of MIMO system can be analyzed from the view of system, and the better approach for each module to improve the system performance can be chose.