中文摘要：

在分析基于最小均方信道估计算法的基础上,对计算量较小的匹配追踪算法进行改进,引入路径门限调整机制以克服虚假路径造成的不良影响,利用重要路径权系数的2次迭代修正方法,进一步提高了水声稀疏信道的估计精度;借助于信道估计值进行均衡系数的解算,利用判决反馈均衡器（DFE）的输出信号对信道估计质量进行实时评估,提出了一种基于DFE的信道长度自适应选择的信道估计算法,同时,通过仿真和实地实验验证了其有效性.结果表明,所提出的算法能够在未知水声环境下实现对信道估计算法的自适应调整以及对预估信道长度的合理选择,以较高的计算效率而实现对水声信道的精确估计,满足未知水声信道环境下的精确信道估计及通信应用需要.

英文摘要：

Based on analysis of the LS-series channel estimation algorithms, the matching pursuit （MP） al- gorithm with small computation amount was improved by importing both a threshold adjusting mechanism which could effectively avoid false paths and an iterative correction method to increase the estimation preci- sion for important coefficients of the sparse underwater acoustic channel. In order to overcome the depend- ence on the information of channel＇s length, a novel channel estimation algorithm which could adapt to real channel＇s length was proposed. Decision feedback equalizer （DFE） coefficients were computed recurring to the real-time channel estimation results while the evaluation of channel estimation＇s quality which could be fed back to adjust channel estimation algorithm was given using DFE＇s output signals. The novel algo- rithm could effectively implement estimations for unknown underwater acoustic environments which also benefited reliable underwater acoustic communications. The proposed method was validated by simulations and experiments.