Abstract: By analyzing the relationship between basis expansion model (BEM) and Doppler spectrum, the authors propose a scheme based on fractional BEM for the estimation of doubly selective channel parameters. When the receiver detects the maximum frequency of Doppler-spread, the frequency of BEM is modified by a factor of 1/K, and improved mean-square error of channel can be obtained.

Key words: channel estimation, doubly selective channel, basis expansion model (BEM), mean-square error

摘要： 通过分析复指数基扩展模型（BEM）与多普勒扩展频谱之间的关系，提出一种基于分数倍基扩展模型的双选信道估计方法。当接收机能够获得最大多普勒频率值时（可以通过自身运动速度等计算或者作相应估计），通过相应调整BEM基频率为原来的1/K倍，信道估计的均方误差性能得到明显改善。另外，还提出了重叠利用训练符号的改进算法，研究表明改进算法可以进一步提高信道估计的质量。

关键词: 信道估计, 双选信道, 基扩展模型, 均方误差