Research On Frequency Offset Estimation And Synchronization Technology Of MIMO System

MIMO technology has attracted the attention of communications industry due to its excellent anti-fading performance and high frequency spectrum utilization.However,MIMO technology,like other high-speed communication technologies is restricted by its synchronization performance during transmission.This problem has become a key issue for the success or failure of MIMO communication system.In this paper,the methods to improve the synchronization performance of MIMO communication system are studied,including the precise frequency offset estimation method which is closely related to the synchronization performance and the method which can expand the range of frequency offset estimation.In this dissertation,a simulation test platform based on the basic model of MIMO communication system is built.The platform verifies the specific relationship between the number of antennas and channel capacity in MIMO communication system,and analyzes the influence of synchronization performance on the bit error rate performance of MIMO communication system.The synchronization performance of the wideband communication system can be effectively improved by accurately estimating the synchronization performance of the system,such as frequency offset estimation range,estimation mean value and estimation accuracy,so as to improve the transmission efficiency and reliability of the system.Therefore,this dissertation studies the basic method and the existing optimization method of the maximum likelihood estimation algorithm,and comes to the conclusion that the maximum likelihood estimation algorithm has a high complexity and is not suitable for practical engineering application.In order to improve the efficiency of the system frequency offset estimation,the dissertation introduces Kay algorithm,Fitz algorithm and L&R algorithm,and studies show that these algorithms can improve the system frequency deviation estimation of computational complexity effectively,but the accuracy and the range of frequency offset estimation are reduced.In order to improve the three methods for frequency offset estimation precision and range of adverse effects,this dissertation studies a kind of adjacent line interpolation method.This method is based on the L&R algorithm derived from the maximum likelihood estimation criterion and the spectrum ratio of adjacent frequency points is used as a correction factor to improve the estimation accuracy and extend the estimation range.Through the simulation test,the results show that the adjacent spectrum interpolation scheme proposed in this dissertation can effectively solve the problem of small estimation range in the L&R algorithm on the basis of ensuring the accuracy of frequency offset estimation,and has certain application value in improving the synchronization acquisition,synchronization tracking and frequency offset estimation of MIMO communication system.