Modified Combined-Step-Size Affine Projection Sign Algorithms for Robust Adaptive Filtering in Impulsive Interference Environments

Abstract

In this paper, to further improve the filtering performance and enhance the poor tracking capability of the conventional combined step-size affine projection sign algorithm (CSS-APSA) in system identification, we propose a simplified CSS-APSA (SCSS-APSA) by applying the first-order Taylor series expansion to the sigmoidal active function (of which the independent variable is symmetric) of CSS-APSA. SCSS-APSA has lower computational complexity, and can achieve comparable, or even better filtering performance than that of CSS-APSA. In addition, we propose a modification of the sigmoidal active function. The modified sigmoidal active function is a form of scaling transformation based on the conventional one. Applying the modified function to the CSS-APSA, we can obtain the modified CSS-APSA (MCSS-APSA). Moreover, the extra parameter of MCSS-APSA provides the power to accelerate the convergence rate of CSS-APSA. Following the simplification operations of SCSS-APSA, the computational complexity of MCSS-APSA can also be reduced. Therefore, we get the simplified MCSS-APSA (SMCSS-APSA). Simulation results demonstrate that our proposed algorithms are able to achieve a faster convergence speed in system identification.

Variable-Step-Size Efficient Proportionate Affine Projection Sign Algorithms

“…Observing (9), one can find that µ v is only associated with the small µ rather than μ and µ, which is simpler than the old CSS way [15,17] and means that the proposed CSS method is only needed with one filter to run the whole time in comparison with the conventional combination method (CGCI-M-IPAPSA) [11,18,19]. The modified ( 9) is the step size of the proposed CSS-GCI-M-IPAPSA, which can be viewed as a new variable-step-size (VSS) GCI-M-IPAPSA.…”

“…For proposed VSS-type algorithm: (17) µ * (k τ ) = µ * (0); else Proposed algorithms' update ctrl new = ctrl old , where L 1 = 25 is a threshold value. This condition determination ( 17) is for determining whether a mutation has occurred.…”

Robust Adaptive Estimation of Graph Signals Based on Welsch Loss

“…Due to the merits of adaptive filter [68][69][70][71], the graph sampling with adaptive strategy has been proposed and developed in [36,[72][73][74][75][76]. Specifically, Lorenzo et al proposed an adaptive method to reconstruct graph signals by exploiting the use of the least mean squares (LMS) strategy [72].…”

ℒp-Norm-like Affine Projection Sign Algorithm for Sparse System to Ensure Robustness against Impulsive Noise

“…To ensure satisfactory filter performance even in the presence of impulsive noise, several adaptive filtering algorithms derived from L 1 -norm optimization have recently been proposed [10][11][12][13]. A representative algorithm that is robust against impulsive noises is the affine projection sign algorithm (APSA) [11].…”