Research Of Cell Synchronization Technique In LTE-Advanced Systems

After achieving a stage evolution of mobile communication, the3G evolved system represented by LTE has greatlt improved the system communication ability with new idea and system design based on OFDM technique, which is satisfying the future mobile communication for people. But even then, the LTE utilizing lots of next generation communication techniques still does not achieve the performance requirements of IMT-Advanced (the formal title of4G named by ITU) so that with the vigorously promotion of the equipment manufactures and operaters, the3G system has been keeping sprinting to evolve to the4G.The technology requirements of IMT-Advanced demanded by ITU including:Achieving a high commonality of worldwide with a method of cost efficiency based on keeping a smart surppot to universal services and applications; Being compatible to IMT and fixed network services; Having the inter-communication ability to other radio access system; High quality mobile services; User equipments can be used for global range; Convinient applications, services and equipments; Global roaming ability.The synchronization is described as the process that the eNodeB sends synchronization signal and some other related channel signal (PBCH signal with Master Information Block MIB and PDSCH with System Information Block SIB) with cell information to User Equipment (UE) to make it get Cell ID then distinguish cells. After finishing time and frequency synchronization, UE can get cell system information. Synchronization occur while UE power on or doing cell-reselection, which is the initial and most important process for UE to establish communication links with eNodeB. The LTE and LTE-advanced systems that use the OFDM mode critically require the time and frequency. The OFDM system which emphasized the orthogonality of subcarriers in order to ensure the reliability is very sensitive to time offset and frequency offset so that the cell synchronization process is very important and the time and precision demanded by synchronization are rather significant indices for measuring it. This paper entirely researched the whole process of LTE-advanced access process, based on which establishing an entire cell search and synchronization link and then promoting some improving algorithms within the synchronization process including:(1) Improving segmentation correlation algorithm in the Primary synchronization signal detection process;(2) Improving the method of cell-group ID obtaining in the Secondary synchronization signal detection process;(3) Improving the channel estimation algorithm of PBCH analysis process;(4) Building up the system plat and test the synchronization performance.