Channel Massive MIMO Pilot Design And Channel Estimation

Multi-antenna system(MIMO)utilizes transmission diversity and spatial multiplexing to fully exploit the dimension resources and improve the transmission efficiency and communication quality.With the development of communication technology,multi-user MIMO in 4G cellular networks can not improve the spectrum efficiency and energy efficiency in order to meet the large capacity,low power consumption and low cost requirements of communication letters.The future 5G network proposes to arrange a large number of antennas at the base station,serve multiple cell users on the same time-frequency resource blocks,increase the power of the useful signals,thereby increasing the signal-to-interference ratio,which can significantly overcome the influence of channel fading and noise,Processing capacity has been significantly improved.In this paper,two kinds of Massive MIMO frame structures are introduced,and the reasons of using the TDD mode are described.Massive MIMO TDD system model and pilot pollution are introduced.The uplink transmission and channel estimation are analyzed in detail.,Uplink data transmission and MRC detection,downlink data reception process,and build Massive MIMO system simulation platform,gives the simulation flow chart analysis of the traditional pilot design LS estimation and MMSE estimation performance.Afterward,the principle of semi-orthogonal pilot design of single-cell is introduced under the framework of Massive MIMO system,and a semi-orthogonal pilot correction scheme is proposed.The design principle and frame structure of the modified pilot are given,and the uplink and downlink transmission process and performance of the pilot design are studied.Compared with the traditional pilot and semi-orthogonal pilot,the pilot scheme is given Program simulation flow chart,in the previously established Massive MIMO simulation platform for different pilot design performance comparison.Finally,two multi-cell cooperative channel estimation methods are introduced.The first is based on Bayesian estimation of collaborative channel estimation.Firstly,the Bayesian estimation principle is introduced,and the Bayesian estimation of mean square error,arrival angle and covariance matrix is analyzed.Then,a cooperative channel estimation strategy is proposed based on Bayes estimation.The user is grouped to find a group of users whose channel estimation mean square error is the smallest Simultaneous channel estimation.The second is a cooperative channel estimation based on TCGTR.This method is used to expand the semi-orthogonal pilot design of the second chapter and apply it to the multi-cell system.The TCGTR estimation process is described in detail.The estimation method is better than the traditional channel estimation method.