一种新的变步长LMS自适应滤波算法及其仿真

A Novel Variable Step Size LMS Adaptive  Filtering Algorithm and Its Simulation

  • 摘要: 传统变步长LMS算法存在收敛速度慢、易受噪声影响等缺点,为了提高算法性能,论文建立了LMS算法中步长因子μ(n)和误差信号e(n)的相关统计量之间的非线性关系,提出了一种基于改进的双曲正切函数的变步长LMS(HTLMS)算法。算法采用当前误差与上一步误差乘积的绝对值来调节步长,并引入了绝对估计误差的扰动量来更新自适应滤波器抽头向量,因而具有收敛速度快、噪声抑制能力强和稳态误差低等特点。计算机仿真结果表明,在不同信噪比条件下,与多种LMS算法相比,本文算法都具有较快的收敛速度和较好的稳态误差。

     

    Abstract:  The common variable step size LMS algorithms have many drawbacks, such as the poor performance of the step function, the fixed parameters and the sensitivity to noise. The paper presents the HTLMS algorithm based on modified hyperbolic tangent by setting a nonlinear function between estimation error e(n) and step size factor μ(n). In the algorithm, the step size factor is adjusted by the absolute value of the product of the current and former errors. The algorithm also introduces the disturbance of the absolute estimation error to update the tapping vector of the adaptive filter, thus the algorithm has faster convergence speed, better performance of noise suppression and lower steady state error. The simulation shows that compared with several LMS algorithms, the novel algorithm has faster convergence speed and better steady state error under different SNR conditions.

     

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