Research On Channel Modeling And Capacity In 3D MIMO System

Three dimension multiple input multiple output(3D MIMO)system increases the vertical coverage of a cell by adopting a three-dimensional beamforming technique,thereby more effectively avoiding inter-cell interference,increasing system throughput,and improving spectral efficiency,is one of the key technologies of the next generation wireless communication system(5G).The system physical channel model is established by introducing the elevation angle of the signal propagation,but this model is limited by specific propagation scenarios and requires a large amount of measured data,which is not conducive to the theoretical analysis of the channel.In order to solve this problem,a tensor-based 3D Kronecker correlation channel model is established for theoretical research in this paper,and the approximate calculation of the capacity of the 3D MIMO system is deeply studied.The major work of this article is as follows:Firstly,the 3D MIMO channel is described by the three-dimensional channel state information tensor in the transmitter,receiver and frequency domain,and a 3D MIMO physical channel model based on the three-dimensional tensor is established.Then a universal coupling-based modeling framework is proposed,that is,the channel state information tensor is decomposed into the product of the coupling tensor,the complex Gaussian tensor and three unitary matrices.Finally,based on this modeling framework,the correlation matrices of the transmitter,receiver and frequency domain are deduced respectively,thereby establishing a tensor-based 3D Kronecker channel model.Through Monte Carlo simulation,this model is compared with the physical tensor channel model,and the accuracy of the model is verified.In addition,the channel performance of this model is also simulated and analyzed.Secondly,this article uses a 3D Kronecker channel model based on Kronecker product,and this model is used in the approximate analysis of 3D MIMO ergodic capacity.Based on the Taylor series expansion,we analyze the ergodic capacity of single-user system and multi-user system respectively and deduce the corresponding approximate capacity expression.The simulation verifies the accuracy of the capacity approximation.Finally,the approximate capacity is used in multi-user scheduling problem,for the classic Maximum Carrier to Interference(Max C/I)scheduling algorithm,a new scheduling function based on second-order approximate capacity is proposed.Simulation shows that its system capacity can well approximate the capacity of the Max C/I scheduling algorithm.