Research On Massive MIMO Transmission Technology

4G changes life and 5G changes society.Compared with 4G,5G improves transmission rate and spectrum utilization,reduces transmission delay,increases system capacity,and pays more attention to user needs.Massive MIMO,as a key technology of 5G,has advantages that traditional MIMO cannot match.Based on the study of the key technologies of Massive MIMO,this paper proposes a Massive MIMO precoding scheme based on the number of channel conditions for the problem of channel instability affecting signal transmission.For the difficulty of large-scale complex matrix inversion,a convergence factor is proposed Neumann series expansion inversion algorithm;Aiming at the problem of multi-cell and multi-user pilot pollution,a pilot allocation algorithm based on service-level priority is proposed.The research work of this paper is mainly divided into the following three parts:1)Based on the study of Massive MIMO precoding,a Massive MIMO precoding algorithm based on the number of transmission channel conditions is proposed.This algorithm dynamically adjusts the transmit power by detecting the difference in the number of transmission channel conditions.The error of the algorithm is simulated performance and research results show that the algorithm not only overcomes the interference between users,but also overcomes the problems of channel instability affecting signal transmission.Compared with ZF and MMSE precoding,it can effectively reduce the bit error rate.2)Based on the study of low-cost,high-order matrix inverse operations,a Neumann series expansion inversion algorithm based on the convergence factor is proposed.In order to enhance the applicability of the Neumann series,a convergence factor is introduced and obtained through the idea of binary search The optimal convergence factor.The error performance of the algorithm is simulated.The results show that the algorithm can effectively replace the direct inverse operation of the matrix with the appropriate convergence factor and maximize reduce the number of iterations.3)Based on the study of traditional pilot pollution mitigation schemes,a service priority-based pilot pollution mitigation algorithm is proposed to divide the community service priorities,assign different pilot sets to different service priorities,and introduce pilot pollution intensity.In this concept,if the user's pilot pollution intensity is greater than the threshold,a special pilot is assigned,and the user's average reachability and rate and mean square error of the algorithm are simulated.The research results show that the algorithm can effectively reduce the pilot pollution and improve overall system performance.