›› 2011, Vol. 31 ›› Issue (6): 58-64.doi: 10.3780/j.issn.1000-758X.2011.06.009

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Robust Timing and Frequency Synchronization under Multipath Fading Channel for Orthogonal Frequency Division Multiplexing  Systems

LIU  Cheng-Zhen1, JIN  Peng-Jia1, WU  Xue-Ying2   

  1. (1 Shanghai Aerospace Electronic Co. Ltd, Shanghai 201821)(2 China Academy of Space Technology, Beijing 100094)
  • Received:2011-04-07 Revised:2011-12-25 Online:2011-12-25 Published:2011-12-25

Abstract: A synchronization scheme for  orthogonal frequency division multiplexing (OFDM) systems based on a novel training sequence was proposed. The training sequence consists of only one centrosymmetric OFDM symbol with two identical parts to  achieve reliable timing and frequency accuracy in the time domain. After coarse timing and fractional frequency synchronization  achieved, a successful estimation was declared for both channel path timing and integer frequency offset by IFFT algorithm which can largely reduce the computational load of the algorithm. For fine timing synchronization, a metric called signal to interference ratio  (SIR)was devised. Based on this metric, a fine timing synchronization method was developed to improve the timing precision. Comparison of the proposed fine adjustment algorithm and conventional synchronization algorithms by using computer simulation illustrates  that the method is more robust to multipath and pseudo multipath.

Key words: Orthogonal frequency division multiplexing, Synchronization, Multipath channel , Satellite communication