Research On NOMA System Model And Transmission Mechanism Based On Large Scale Dual-Polarized MIMO

With the rapid development of mobile Internet and Internet of Things,a variety of business scenarios have emerged,such as remote surgery,immersive experience,smart home and Internet of Vehicles.These diverse business scenarios require differentiated performance requirements,such as data rate,delay,reliability and connectivity density.It is difficult to meet the requirements.Under the above background,the fifth-generation mobile communication(5G)facing 2020 and the future has become a global research and development hotspot.The 5G technology is a new generation mobile communication technology facing the diversified needs.It is a communication network that integrates many technologies and meets the future mass data transmission.The development of transmission and super intensive connection business needs to be improved,and the quality of user experience is greatly improved.In wireless communication systems,multiple access technology is a necessary way to achieve simultaneous communication between multiple users.The update of every generation of mobile communication system is accompanie d by the emergence of new multiple access technology.In order to meet the requirements and challenges of 5G,the technology of combining time,space,polarization,power and other dimensions of resources has attracted wide attention and research.This dissertation focuses on the model and transmission mechanism of NOMA system based on large-scale dual-polarization MIMO.It focuses on the interference suppression in dual-polarization MIMO-NOMA transmission.A precoding method suitable for dual-polarization MIMO-NOMA transmission is designed to effectively suppress intra-cluster and inter-cluster interference and reduce transmission errors.Rate and improve the spectrum efficiency of the system,improve system performance.The precoding method of non-interference transmission is explored in the scenario of cluster of cell center users and cell edge users with similar spacing.Nowadays,the traditional NOMA system mainly realizes multiplexing in power domain,which is based on the difference of channel conditions between two users.However,it is difficult for the system to realize normal transmission when the channel conditions of two users are not too different.Aiming at this challenge,this dissertation introduces the polarization domain,and utilizes the properties of Kronecker product and the characteristics of large-scale MIMO to realize the non-interference transmission of the system.Finally,the proposed precoding algorithm is simulated to verify its impact on system performance.The appropriate precoding method is explored in the scenario where the center users and the edge users are clustered.When the number of base station antennas is very large,it is difficult for the precoding system to obtain channel state information in time and accurately,which makes the final signal demodulation process difficult to achieve smoothly.In the improved precoding algorithm,the polarization fading of the channel and the slow change of spatial correlation are utilized.Simulation results show that the performance of the NOMA system using this algorithm is better than that of other NOMA systems under the same conditions.Considering that the reuse of power domain resources can improve the spectrum efficiency of the system,and the reasonable utilization of polarization domain resources can significantly reduce the complexity of the system,the co-polarization center users and edge users in a single cell downlink transmission system are clustered in pairs to optimize the users after the inter-cluster and intra-cluster interference are suppressed at the user receiving end.The distribution of signal power is used to enhance the spectrum efficiency of the system.After that,the performance of the system is explored in the presence of two kinds of user clustering.