Noise reduction for VoIP speech codecs using modified wiener filter

Abstract

Noise reduction is essential to achieve an acceptable QoS in VoIP systems. This paper proposes a Wiener filter-based noise reduction scheme optimized to the estimated SNR at each frequency bin as a logistic function is used. The proposed noise reduction scheme would be applied as preprocessing before speech encoding. For various noisy conditions, the PESQ evaluation is performed to evaluate the performance of the proposed method. In this paper, G.711, G.723.1, and G.729A are used as test VoIP speech codecs. The PESQ results show that the performance of our proposed noise reduction scheme outperforms those of the noise suppression one in the IS-127 EVRC and the noise reduction one in the ETSI standard for the advanced distributed speech recognition front-end. © 2007 Springer.