Journal of Applied Sciences ›› 2012, Vol. 30 ›› Issue (6): 573-580.doi: 10.3969/j.issn.0255-8297.2012.06.003

• Communication Engineering • Previous Articles     Next Articles

Decision Directed Channel Equalization for OFDM Underwater Acoustic Communications

MA Xue-fei1, QIAO Gang1, ZHAO Chun-hui2, MA Lu1   

  1. 1. National Laboratory of Underwater Acoustic Technology, Harbin Engineering University, Harbin 150001, China 
    2. College of Information and Communication Engineering, Harbin Engineering University,Harbin 150001, China
  • Received:2010-10-20 Revised:2011-08-10 Online:2012-11-27 Published:2011-08-10

Abstract: Complication of ocean channels causes sub-carrier amplitude fading and phase distortion in underwater communication. To reduce the effects of channel estimation error due to time variation and interpolation error, a decision-directed channel equalization algorithm for OFDM-based communication is proposed. Error control codes are used for decision making so that the data decisions can be used as pilots, with which channel estimation is performed. Taking into account different environment conditions, equalization is done using a decision-directed scheme with block piloting and a decision twice-equalization scheme with comb piloting. Results of simulation and lake experiments are promising, showing that the proposed scheme can effectively
improve system performance without loss of bandwidth efficiency.

Key words: underwater acoustic communication, orthogonal frequency division multiplexing (OFDM), channel equalization, decision equalization

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