Analysis Of MIMO Channel Based On RMT

MIMO technology is paid more and more attention because it can improve capacity without increasing the bandwidth, and the capacity is one of the very important indexes which is used to measure a MIMO communication system performance and had a lot of in the past paper. But since the actual channel state varies over the time and has some randomicity, so the research about MIMO system mainly based on ergodic capacity and outage capacity which are of statistical significance.According to the characteristics of wireless channel, it is classified as flat fading channel and frequency selective fading channel or fast fading channel and slow fading channel. This thesis mainly studied the ergodic capacity of the slow fading channel under the spatial correlation conditions. The calculation formula of the ergodic capacity based on the probability density function of Wishart matrix is derived. Moreover, according the characteristic of Wishart matrix's distribution and the Jansen inequality, the upper and lower limit of expressions of the channel capacity about the full spatial correlation channel are derived.The results obtained by Matlab numeric calculation show that, the value calculated by the formula derived in this thesis is very closed to the value derived by Monte Carlo method. Along with the numbers of receiver and the transmitter antenna increasing, the Monte Carlo method's operand increased greatly, but the method in this thesis gets the results which have approximate calculation accuracy compared with the Monte Carlo method quickly. Moreover, with the Signal-to-Noise Ratio (SNR) increasing, the curve of the correlated fading channel on the lower limit is closer to the curve of the channel capacity. And discussing the interrelation between the channel capacity and the three important parameters (antenna distance, incoming wave angle and angle expansion) based on the results of Matlab numeric calculation.