Research On Synchronization Technology Of OFDM System

Orthogonal Frequency Division Multiplexing is one of key technologies in mobile communication fields, it is suitable for high rate data transmission in wireless channels because it can combat Inter-Symbol Interference and multi-path fading efficiently, now it has become an attractive technology. OFDM is a multiple carriers technology, supports high rate data transmission with high spectrum efficiency. At present, OFDM technology has been used in many fields, such as wireless local network, digital audio broadcasting (DAB), digital video broadcasting (DVB) systems and so on. It is very promising to be a core technology of the fourth generation mobile communications.First, the history and the recent development of OFDM technology are introduced. The importance of the synchronization in OFDM system is described, and the main work and contributions of the writer are briefly introduced. The model of OFDM system is also introduced, including the basic characteristics and the key technologies of the OFDM systems. The effects of synchronization errors on demodulation performance are discussed, including frequency offset and timing offset. The effects on demodulation results are analysed and a approaching estimation of SNR degradation when synchronization errors exist is given.Then, timing synchronization algorithms are discussed. To timing synchronization, the complexities and the performances of multiple estimators using cyclic prefix are discussed, simulation results are given and several conclusions are made. Besides this, Schmidl&Cox timing estimator which estimates timing offset by pilot sequences is discussed. A simplified sliding windows timing estimator is proposed. When the window length is two times as...