Research On Joint Spatial Division And Multiplexing Algorithm In Massive MIMO System

Massive MIMO technology can greatly improve the spectrum efficiency,energy efficiency and communication quality of the system by increasing the number of antennas of the sender and receiver.It is considered to be the main technology of the new generation mobile communication system.In Massive MIMO systems,the acquisition of Channel State Information(CSI)is the key to its high system performance.However,due to the large number of antennas at the base station,the acquisition of CSI requires a large amount of system resources.In order to solve this problem,the idea of Joint Spatial Division and Multiplexing(JSDM)is proposed in the Frequency Division Duplexing(FDD)massive MIMO system.This paper focuses on the study of JSDM algorithm.The main work is as follows:1.An energy efficiency optimization algorithm for Massive MIMO systems based on JSDM is proposed.The algorithm takes advantage of JSDM to effectively reduce system overhead and apply JSDM to the analysis of energy efficiency problems.Compared with the energy efficiency optimization algorithm based on equal power allocation and Lagrange-based energy efficiency optimization algorithm under the same system power consumption model,the simulation results show that when the transmit power is small,the JSDM algorithm can reduce system overhead while maintaining better system energy efficiency.2.A WMMSE-based JSDM algorithm is proposed and applied to the sum rate optimization problem of Massive MIMO systems.In the implementation of the secondstage precoding matrix of the traditional JSDM,inter-group interference is ignored.The algorithm proposed in this paper takes advantage of Weighted Minimum Mean Squared Error(WMMSE)to take the inter-group interference into account.By using the equivalence relation between the sum rate maximization problem and the WMMSE minimization problem,the solution of the maximum sum rate is transformed into the solution of the minimum weighted mean square error.By analyzing the simulation results,it is proved that the proposed WMMSE-based JSDM algorithm can effectively improve the system sum rate in the region of medium and low SNR.Through the simulation results,the influence of effective rank on the performance of the algorithm is analyzed,and it is shown that the effective rank size should be selected according to the distribution of eigenvalues of the covariance matrix.