The Research On Channel Estimation Based On Tensor Decomposition In 3D MIMO System

In recent years,with the emergence of various communication services,the demand for data traffic has gradually increased,and in this context,wireless communication systems are encouraged to provide higher system spectral efficiency.In the new generation of mobile communication systems,more technologies have emerged to improve the spectral efficiency of the system,such as massive MIMO systems,3D MIMO systems,millimeter wave systems,and the like.The 3D MIMO system not only provides the channel gain brought by the large antenna through the antenna array of the high-dimensional structure,but also utilizes the degrees of freedom in the horizontal and vertical dimensions to greatly improve the system capacity and spectrum utilization.In order to make full use of the degrees of freedom in 3D MIMO systems and obtain higher spectral efficiency,it is very important to obtain channel state information at the transmitting end,but in 3D MIMO systems,channel estimation is performed due to the antenna array of high-dimensional structure.There are certain challenges.As a branch of mathematics,tensor technology has unique advantages in dealing with high-dimensional arrays.This paper intends to use the tensor theory to analyze the 3D MIMO estimation algorithm and propose a channel estimation scheme based on tensor theory.The main work of this thesis is as follows:First,the definition and properties of tensors are introduced.Through its various definitions and mathematical operations,it shows the characteristics and advantages of tensors in processing high-dimensional arrays.At the same time,the concept and function of tensor decomposition are introduced.Tensor decomposition is an important concept in tensor theory.It can analyze a high-dimensional array and obtain its inherent essential features.Secondly,the channel estimation scheme of 3D MIMO system based on tensor decomposition theory is studied.In the 3D MIMO system,since the two-dimensional antenna array is adopted at the base station,the channel of the system can be expressed in the form of a high-dimensional array,and the conventional matrix channel estimation scheme will greatly increase the computational complexity of the channel estimation scheme.As an effective mathematical method for processing high-dimensional arrays,tensor can better deal with the problem of 3D MIMO channel estimation.By using the tensor technique,the input and output equations of the 3D MIMO system are first given.Secondly,the problem of 3D MIMO channel estimation is expressed as the problem of tensor decomposition.Then the tensor decomposition technique is used to obtain the channel estimation scheme effectively.Thirdly,the tensor decomposition theory can better solve the channel estimation problem in 3D MIMO systems,but due to the influence of noise,the tensor decomposition accuracy needs to be improved,and the channel estimation performance is degraded.In order to reduce the inaccuracy of tensor decomposition,in this paper,a tensor decomposition theory based on orthogonal factor is proposed to solve the channel estimation problem of 3D MIMO systems.The scheme makes the transmitted pilot sequence satisfy the orthogonal condition,reduces the uncertainty of the tensor decomposition process,improves the accuracy of the tensor decomposition process,and effectively improves the performance of channel estimation scheme of the 3D MIMO system based on tensor theory.