Research On Synchronization Algorithm In OFDM System

Orthogonal frequency division multiplexing (OFDM) has become the key technique in broadband wireless access and the next generation mobile communication system. Extensive attentions have been paid to OFDM due to its high spectral efficiency, high data rate and well anti-multipath ability. As a special muticarrier modulation,OFDM is very sensitive to both timing synchronization error and carrier frequency offset. So it is a key technique for OFDM system to keep good performance. And now synchronization in OFDM has become a hotspot in the research of modern communication.In this paper, the evolution history of wireless communication and OFDM system is reviewed, and the fundamental principles in OFDM are briefly introduced. After analyzing the effects of synchronization errors to the system performance, many kinds of synchronization algorithms, such as the cyclic prefix {CP) based, virtual subcarried based and training symbol based joint symbol timing and also the carrier frequency synchronization algorithms are introduced and discussed in detail. The system simulations and performance analyses are made to each algorithm.Based on analyses of the existing algorithms, A novel approach is introduced with time training sequence.After obtaining exact time deviation,we compute coarse carrier frequency offset based on the method of carrier phase,then we get the fine frequency estimation after compensation for OFDM system.The result of computer simulation has showed that good performance has obtained by the new algorithm.Besides, compared to Schmidl's method,the proposed algorithms can attain improved spectral efficiency. .