System for detecting defective speech frames in a receiver by calculating the transmission quality of an included signal within a GSM communication system

摘要

A method for detecting defective speech frames in a receiver of a speech communication system includes a coded speech signal consisting of speech frames conveying speech coding parameters received through a transmission link. The detection method for defective speech frames depends on the quality of the transmission link. If the quality of the transmission link is "poor", unusual parameter values of a speech signal in a speech frame are interpreted as transmission errors, and the speech frame is classified as defective. During a transmission link of "good" quality, all received parameter values possible for speech are accepted and forwarded to a speech decoder. In the latter mode of operation, the detection of defective speech frames is solely based on conventional error detection methods employed in the receiver.