Analysis of Interpolated FIR Filter for VoIP in Noisy Enviroment

The presence of background noise degrades the quality of speech signal. The speech quality of the VoIP system can be improved by reducing the background noise, codec distortion and various network impairments such as packet loss, delay and jitter. The work in this paper proposes the Interpolated Finite Impulse Response filter (IFIR) based scheme for reduction of noise. The IFIR filter would be applied as post processing after the speech decoding. For various noisy conditions, the quality of speech signal is measured with PESQ measurement to evaluate the performance of the proposed method. The codec tested with proposed method are G.729A and AMR-NB. The performance is evaluated not only for the codec used but also for VoIP system with packet loss in noisy environment. The results show much improvement in speech quality with proposed method.