Performance analysis of an efficient AIFIR echo-tail canceller

A computationally efficient two-stage echo canceller is proposed. The first stage is a direct form adaptive FIR filter to cancel the main part of the echo response. The second stage cancels the `tail´ part of the echo response. The proposed tail canceller is an adaptive version of the interpolated FIR (IFIR) filter. It is shown that the two-stage canceller meets the 60 dB echo cancellation accuracy for various Bellcore loops. Extensive simulations were carried out to study the effects of the main canceller length as well as the interpolator parameters on the performance of the two-stage echo canceller in the U-interface transceiver for basic rate ISDN. It is shown that the proposed structure compares very favorably with other proposed two stage cancellers