7. The method of claim 6 wherein the given threshold is reduced based on a spectral difference between the target packet and one or more of the reference packets and based on a perceptual difference between pitch parameters of said target packet and of said one or more of the reference packets.
6. The method of claim 1 wherein the step of detecting the echo in said target speech signal comprises determining if the target speech energy level is lower than said one or more of said reference speech energy levels by at least a given threshold.