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针对正交频分复用信号通过快速傅里叶变换变换得到的频谱不够精确且计算量较大的问题,提出一种基于Welch法的带宽盲估计方法.首先用Welch法求得功率谱,再进行小波分解、重构,得到平滑的功率谱;然后提取出最大移动协方差的2个值所在的位置进而估计带宽;最后多次循环求统计平均,得到信号的精确带宽.实验仿真结果表明:在多径且低信噪比为0dB的条件下,该方法的正确估计率达99.1%,比传统方法的带宽估计精度更高,计算复杂度更低.
Aiming at the problem that the frequency spectrum obtained by fast Fourier transform of orthogonal frequency division multiplexing signal is not accurate enough and the computation is large, a method of blind bandwidth estimation based on Welch method is proposed. First, the power spectrum is obtained by Welch method, and then And then get the smooth power spectrum; then extract the location of the two values of the maximum moving covariance and then estimate the bandwidth; Finally, the statistical averaging is repeated for multiple cycles to get the accurate bandwidth of the signal.Experimental results show that: Under the conditions of multipath and low signal-to-noise ratio of 0dB, the correct estimation rate of this method is 99.1%, which is more accurate than the traditional method and has lower computational complexity.