Research On Capacity Of Spatial Correlated Multi-User MIMO System

Multiple input and multiple output(MIMO) technology can improve the channel capacity and the performance of wireless communication system greatly without additional bandwidth and transmit power and therefore it’s becoming a hotspot. On the basis of existing research, the thesis mainly researches on the capacity of spatial correlated MIMO system and the key technologies of MIMO system in free space, the subject has theoretical significance and application value. The main work of this thesis is as follows:1. Under the condition of flat fading channel, the Kronecker model is introduced based on the relevant characteristics between antennas. Then we deduced the expression of spatial correlation for the uniform linear array with different angle power spectrum distribution and study the effect of azimuth spread and antenna spacing on the channel matrix.2. The approximate expression for the ergodic capacity of correlated single-user MIMO system is derived. And also we simulate the channel capacity with spatial correlation under different azimuth spread、antenna spacing and average angle of arrival. Then we analyse the effect of self-adaptive water-filling power allocation on the capacity of corrected channel and results show that correlation between antennas increases the MIMO capacity when the signal noise ratio is low enough.3. Based on large-scale random matrix theory, we study the capacity of multi-user MIMO system by means of deterministic equivalent. Moreover, the specific algorithm of generalized water-filling power allocation is derived when the statistical channel state information is available at the transmitter. Simulation results indicate that the deterministic equivalent shows great accuracy when calculating per-antenna sum rate.4. In the airborne MIMO environment, the thesis carries out a simple analysis on the capacity of ideal line-of-sight channel and rayleigh fading channel. The free space broadband MIMO system based on single-carrier frequency domain equalization(SC-FDE) and orthogonal frequency division multiplexing is put forward respectively, and the capacity of the two systems is analysed. In SC-FDE system, we consider the influence of time delay between antennas on channel capacity and simulated results show that the intersymbol interference improves the system capacity when using space-time joint processing method.