Research On Hybrid Precoding Method In Millimeter Wave MIMO Systems

At present,the research on 5G technology is in full swing.The goal of future wireless communication is to provide higher transmission rate and larger channel capacity to meet the communication needs of all things.However,it is unrealistic to meet this goal in the traditional lowfrequency spectrum,therefore,The combination of millimeter-wave and large-scale MIMO technology is a direction of 5G research.The hybrid precoding technique is an important signal processing method in millimeter-wave MIMO systems.It can resist multipath fading,reduce interference between data streams,and improve spectral efficiency.Based on the full-connection structure,this paper proposes a hybrid pre-coding method based on minimum iteration.In order to improve the spectral efficiency,the design of hybrid precoder is transformed into the optimal precoding matrix without constraint and the Euclidean distance of hybrid precoding matrix.By implementing the orthogonal constraint on the digital precoder,the precoding and simulation precoding matrices are separated,and the approximate optimal hybrid precoding matrix is obtained through iteration of the loop.In order to further reduce the complexity of the system,a partially connected structure is proposed based on the fully-connected structure.First,the idea of continuous interference cancellation is used to convert complex channel capacity into independent sub-capacity,in order to obtain the maximum system capacity of the channel.Then,a new zero-forcing precoding algorithm is proposed based on this.The simulation results show that the proposed hybrid precoding algorithm can approach the full-joint pre-coding algorithm to the maximum extent with a large complexity reduce.For the millimeter-wave MIMO system,a novel antenna array structure-hybrid connection structure is proposed,that is,one antenna sub-array is connected to each radio frequency chain,and the internal connection of each antenna sub-array is a fully connected structure.,To design a hybrid precoder.The simulation results show that the spectral efficiency of the hybrid connection structure is between the partial connection structure and the full connection structure.The hybrid connection structure not only reduces the complexity of the full connection structure,but also further improves the system performance of some connection structures.