Three Dimensional MIMO Channel Modeling And Its Performance Analysis

In recent years, the rapidly explosive demand leads to the long-time evolution in wireless communication systems. In wireless communication system design,wireless channel modeling occupies an important position, which is necessary prerequisite to establish high-quality wireless communication system. The technology of MIMO has been widely concerned because of its ability to effectively solve the problem of limited wireless spectrum and improve the channel capacity.However, the performance of the system is affected by the wireless fading channel and antenna array. And signal transmission quality is associated with the characteristics of wireless channel. So the establishment of an effective and accurate channel model is very important. This paper centers on analysis of geometrical-based wireless statistic channel and research the correlation and capacity of MIMO system. The paper mainly has the following sections:Firstly, the large-scale fading and small-scale fading are introduced in wireless channel. In addition, several common large-scale fading model and small-scale fading model were proposed. Moreover, the probability distributions of several scatterers in the channel model are described in detail, which is beneficial to study the characteristics of channel model in real life.Secondly, a channel model which is more suitable for describing the macrocell environments is proposed. Generally, the antenna in the macrocell environment is higher than that of all the nearby buildings, which is to reduce the influence of the multipath effect. However, this is not the case, so it is necessary to establish a more accurate and effective channel model. In this model, scatterers are gaussian distributions. And the model can describe the important space-time parameters precisely, such as angle of arrival, time of arrival and doppler shift. The simulation results are compared with other models,which shows that the model is more suitable for describing the macrocell environments in the real situation.Thirdly, the above channel model can be improved. Under the environment of asymmetric space, a modified channel model is proposed. This model not only can accurately describe the important space-time parameters under the asymmetric propagation environment, but also can be applied to MIMO system performance simulation. By analyzing the numerical simulation results of the linear antenna array and the circular antenna array, it is found that the circular antenna array is better.Fourthly, the paper proposes a three-dimensional MIMO channel model which is appropriate in indoor microcell environments, which extends from two-dimensional analysis to three-dimensional spatial domain analysis and increases the analysis of signal on the vertical plane. In this model,there is no scatterer around the mobile station that is as the central origin, and the directional antenna is also placed at the base station. The space-time channel parameters on both horizontal and vertical planes can be derived, such as the probability density functions of AOA and TOA. Compared with the simulation results, the MIMO channel model can be applied to the mobile communication environment of indoor microcell, which provides a flexible model for three-dimensional spatial domain channel research.Lastly, based on the three-dimensional spatial domain, a new model of a two-cylinder channel model is proposed. In this model, it is assumed that the scatterers are evenly distributed. The model can accurately describe the important space-time parameters of the spatial channel in the outdoor macrocell environment,such as AOA?TOA and DS. The simulation results show that the three-dimensional spatial channel model describes the outdoor macrocell environments better and more accurately than the two-dimensional channel model.