Adaptive combination of affine projection and NLMS algorithms based on variable step-sizes

作者：Ren, Chunhui^*; Wang, Zuozhen; Zhao, Zhiqin

来源：Digital Signal Processing, 2016, 59: 86-99.

DOI：10.1016/j.dsp.2016.07.022

• Affine projection algorithm
• Normalized least mean square algorithm
• Variable step-size
• Mixing parameter
• Mean-square deviation

Considering the filters with variable step-sizes outperform their fixed step-sizes versions and the combination algorithms with proper mixing parameters outperform their components, a combination algorithm consisting of improved variable step-size affine projection (I-VSSAP) and normalized least mean square (I-VSSNLMS) algorithms, of which the former is fast and the latter is slow, is proposed for stationary environment Different from the combination algorithms whose components are updated independently, the variable step-sizes components are adapted using the same input and error signals, and their step-sizes are derived via the mean-square deviation (MSD) of the overall filter. Therefore, the components reflect the working state of the combination filter more accurately than their fixed step sizes versions. The mixing parameter is obtained by minimizing the MSD and gradually decreases from 1 to 0. Therefore the proposed algorithm has a performance similar to I-VSSAP and I-VSSNLMS in the initial stage and steady-state respectively. Simulations confirm that the proposed algorithm outperforms its components and its fixed step-sizes version. The mixing parameter is artificially set to 0 when the difference between the MSDs of two adjacent iterations is below a user-defined threshold, then the proposed algorithm degrades to I-VSSNLMS and exhibits a less computational complexity than AP algorithm.

• 出版日期2016-12
• 单位电子科技大学