Ofdm Synchronization Issues

Orthogonal Frequency Division Multiplexing (OFDM) is a kind of multi-carrier digital modulation technique. Application of the technique started in the 1960s, and mainly used in the military communication. But because of its complex structure limited to expand further. In 1970s, people put forward applying DFT (Discrete Fourier Transform) to carry out the multi-carrier modulation, making the OFDM technique more practicality. With the development of DSP chip technique, high-speed Modem adopted 64/128/256QAM, trellis-coded, soft decision, channel adaptive, guard interval have been introduced gradually. Because of spectral efficiency and robustness against multipath interfering, orthogonal frequency division multiplexing (OFDM) modulation has attracted considerable attention from researchers. OFDM has been adopted as the key transmission technique for the future forth-generation mobile communication systems.One of the main defects of OFDM systems lies in its high sensitivity to synchronization errors. To solve this problem, this paper makes a deep research on the synchronization problems in OFDM systems and a efficient synchronization project is proposed.At first, this paper introduces the developing actuality of the wireless mobile communication. Second, the principle, properties and key technology of OFDM are discussed. And moreover, the symbol synchrony technology, a crucial technology of OFDM system, is researched and analyzed in detail. Then, the effect of synchronization error of an OFDM system is discussed in detail. Finally, based on the analysis of the existing synchronization algorithm, an improved arithmetic is proposed. Simulation results indicate that the improved method has a good performance in synchronization.