ECHO CANCELLER FOR VOIP NETWORKS

摘要

An echo canceller in an IP network includes an adaptive filter that models the echo path between a receiving output port of the echo canceller and a sending input port. The adaptive filter filters a receiving input signal to generate an estimate of an echo signal. The estimate of the echo signal is subtracted from a sending input signal to cancel the echo in the sending input signal and to generate a sending output signal. A packet loss detection circuit detects when packet loss occurs in the echo path. Responsive to detection of packet loss in the echo path, the echo canceller applies packet loss concealment to either the sending output signal or the receiving input signal.

主权项

1. A method of echo cancellation implemented by an echo canceller located in a packet-switched network, said method comprising:
generating, from a receiving input signal received on a first input port of the echo canceller, a first estimate of an echo signal using an adaptive filter that models an echo path between a first output port and a second input port of the echo canceller; generating a sending output signal based on the first estimate of the echo signal and a sending input signal received on the second input port; detecting a packet loss in the echo path; and responsive to detection of the packet loss, modifying one of the receiving input signal and the sending output signal to include a loss-concealment packet.