Modified filtered-X affine projection sign algorithm for active control of impulsive noise

For active noise control problems, when noise sources are contaminated by impulsive noise, the classic FxLMS converges slowly or even diverges. In order to effectively control such impulsive noise sources, by minimizing the Ll-norm of an error vector, a modified filtered- x affine projection sign algorithm (MFxAPSA) has been proposed. An exact efficient implementation can greatly reduce its number of multiplications per iteration from the order of projection order timing controller length to the order of adding them. Therefore, the efficiency improvement over the direct implementation is more impressive when the projection order is high. A variable step-size extension further improves the convergence rate of the MFxAPSA without increasing the computational cost. The superior performances of the proposed algorithms are verified by both synthesized and practical impulsive noise data.