Three Dimensional Spatial Channel Model And The Performance Assessment

Multiple input multiple output(MIMO) is one of the key technologies in the next generation of mobile communication. Three-dimensional(3D) beamforming is a rich potential MIMO technology solution. It controls the antenna radiation direction through dynamic antenna arraies, which can make the radiation direction more directional to enhance coverage and improve the communication quality on the edge of the cell, at the same time it can increase the security capacity of the users. Using 3D MIMO on the basestation can model the arrival angle of vertical dimension more accurately, namely the 3D spatial channel model. This article mainly researches the 3D spatial channel models suitable for different scenarios. Paper’s main work includes:(1) Firstly, we summary the theory of two-dimensional spatial channel model(2D SCM) and the concepts related to MIMO technology, 3GPP TR 25.996 relates to a two-dimensional spatial channel model, which mainly takes into account the angle power spectrum of the horizontal dimension, the vertical dimension spectrum is not considered,When the power spectrum of the vertical dimension is more evident(such as using 3D MIMO on the base station), 2D SCM may fail. Only paying attention to the power spectrum of the horizontal dimension will lead to erroneous results, so we should study correcting 2D SCM.(2) For the reason that 2D SCM doesn’t take into account the power spectrum of vertical dimension, we put forward the first improved three dimensional spatial channel model(3D SCM) which suitable for outdoor-indoor scene, under this kind of model we evaluated how different system parameters such as the downtilt of the base station, the number of sending and receiving antennas, and the 3D to 2D power ratio effect on the rate of mutual information. Finally, downtilt adaptation based on interference control is presented. It realizes beam coordination between two neighboring base stations for improving indoor coverage of the cell edge.(3) The second 3D channel model suitable for outdoor scene is put forward based on 2D SCM, under this kind of model,we evaluate how the system parameters such as different heights of base station and mobile station, carrier frequency influence the user’s security capacity, and then compared the 2D and 3D SCM security capacity change. And then consider the change of user security capacity inside the cell when a neighbor cell interference. Finally, an encryption algorithm using the 3D SCM channel model based on artificial noise is put forward.(4) Firstly, we had a detailed research on 3D SCM which the base station using the uniform planar array. Secondly, we studied how the angle spread(AS) and cross polarization discrimination(XPD) affect the performance of mutual information, and compared the uniform linear array(ULA) and the uniform plana array(UPA) performance. Then we compared the mutual information performance of 2D and 3D MIMO. Finally how the downtilt of basestation effect the small area coverage on the edge of a cell is studied.