| As the criterion of4G, LTE adopts two key technologies of OFDM and MIMO to improve thetransmission performance. OFDM provides an effective broadband transmission technology torealize high spectral efficiency and combat the frequency selective fading deterioration. However,due to its use of multi-carrier, the OFDM system is sensitive to the timing offset and frequencyoffset. The inter-symbol interference (ISI) and inter-carrier interference (ICI) caused by timingdeviation and frequency offset will degrade the achieved performance of OFDM significantly. Howto effectively realize the synchronization in OFDM is a very basic problem for the OFDM system.The purpose of this thesis is to discuss the different synchronization technique candidates forOFDM, and the suitable ones which match the characteristics of the LTE system is highlighted inthis thesis.Firstly, a brief overview of the OFDM techniques are presented to address the impact of thetiming error and frequency offset for OFDM system, some of the existing OFDM timing andfrequency synchronization algorithms are analyzed and compared. Secondly, combined with MIMOtechnology, some classic synchronization technologies for MIMO-OFDM are researched based onthe analysis of the timing error and frequency offset. Finally, taking the LTE physical layer protocolinto account, mainly introduced the TD-LTE synchronization scheme and neighborhood searchsolutions in the LTE system. |
PDF Full Text Request