Research On Synchronization Technology In The New Generation Wireless Communication System

With the continuous development of mobile multimedia,people pursue faster and more reliable communication services.OFDM technology transmits data through multiple subcarriers,and the spectrum of subcarriers overlap each other.It can get very high spectrum efficiency.By adopting multiple antennas in the transceiver,MIMO technology can improve system capacity under the premise of constant transmission of power and communication system.MIMO-OFDM technology is a combination of the two technologies which can save the spectrum resources and improve the transmission capacity of the system.However,MIMO-OFDM system is very sensitive to the time-frequency error,so the good synchronization becomes the key to take the advantages of MIMO-OFDM system.As an evolution of LTE technology,LTE-A can greatly improve the wireless communication system data transmission rate and spectrum efficiency,and meet the new generation of wireless mobile communications business needs.It is necessary to establish the time-frequency synchronization through the cell search and determine the cell number before the user equipment communicates with the base station.This thesis takes the new generation of wireless communication system as the research object,mainly focusing on the synchronization problems of the Distributed MIMO-OFDM system and LTE-A downlink system.The main work can be summarized as follows :(1)Based on the Distributed MIMO-OFDM system,aiming at the poor performance of UPSP algorithm in multi-path environment,an improved timing algorithm is proposed on the basis of studying the existing timing synchronization algorithms.Since the training sequences on different antennas are derived from different partial ZC sequences,and the sequences have good autocorrelation and cross-correlation properties,the improved algorithm can obtain good anti-multipath interference performance,and the effectiveness of the proposed algorithm is verified by simulation.(2)Based on the LTE-A downlink system,aiming at the problem that the traditional PSS detection algorithm can obtain few detection parameters and the poor performance when the system has large frequency deviation,a new PSS detection algorithm is proposed on the basis of studying the existing cell search algorithms.Compared with traditional algorithms,it can obtain the timing position estimation and the CP mode parameters of the data frame.The simulation results verify the effectiveness of the proposed algorithm.In addition,aiming at the problem of neighbor cell SSS detection,an improved algorithm is proposed which is based on anti-jamming factor.It improves the performance of nearby cell search.The simulation results verify the effectiveness of the proposed algorithm.Finally,a complete LTE-A downlink synchronization control scheme is given for the LTE-A downlink,and the hardware simulation of the improved PSS detection algorithm is carried out.