OFDM系统自适应盲信道估计新方法

基于无线通信OFDM系统信道估计，提出了两种时域自适应盲估计方法。这些方法通过对极性(符号)LMS算法（SLMS）进行改进，改进算法有几方面优点，一是继承了极性LMS算法简单易实现的特性；二是解决了极性LMS收敛速度慢的缺点；最后结合自适应可变步长及步长调整策略，有效地提高了算法的估计性能。仿真给出了误差曲线以及归一化均方误差曲线，结果表明，和基于极性LMS盲估计方法相比，修正极性LMS和时变步长修正极性LMS盲估计方法均具有很快的收敛速度。由于采用了变步长技术，时变步长修正极性LMS盲估计方法具有更好的估计性能。 

New blind adaptive channel estimation schemes based on OFDM systems

Two time-domains blind adaptive estimation schemes were proposed based on OFDM systems. Both schemes improved the SLMS and had three advantages. First, the character of easy accomplish has been inherited from LMS. Second, the disadvantage of low speed has been solved. Finally, the estimation performance has been improved by combining adaptive variation step and adjusting strategy. Error curve and normalized mean square error curve are given in simulation, and shows that the modified SLMS and the time-variance step modified SLMS channel estimation schemes have faster converges comparing to the scheme based on SLMS, especially the latter one has better performances.