Proportionate Sign Subband Adpative Filtering Algorithm for Network Echo Cancellers

Abstract

Abstract-This paper proposes a proportionate sign subband adaptive filtering (PSSAF) and an improved PSSAF (IPSSAF) algorithm for network echo cancellers that deal with impulsive interferences and sparse echo paths. Based on a sign subband adaptive filtering (SSAF) algorithm that is robust against impulsive interferences, the proposed algorithm minimizes L 1 -norm of the subband a posteriori error vector subject to a weighted constraint on the filter coefficients. A positive definite weighting matrix is used for the constraint. In this paper, we adopt a diagonal proportionate matrix for the constraint to achieve fast initial convergence rate when the impulse response is sparse. The components of it is roughly proportional to the absolute value of current estimate of the filter, so the resulting algorithm is called PSSAF algorithm. To achieve fast initial convergence rate even for rather non-sparse impulse responses, an improved proportionate matrix is also used for the constraint, and the resulting algorithm is named as IPSSAF algorithm. Experimental results show that the proposed algorithms are more robust against highly correlated input signals, impulsive interferences, and double-talk than the original normalized subband adaptive filtering algorithm and the class of proportionate subband adaptive filtering algorithms.Index Terms-Adaptive filters, proportionate, sign algorithm, subband adaptive filtering algorithm, weighted constraint, weighting matrix.