Abstract: The error concealment method improves the signal quality in transmission systems. The method is used for processing speech signals which have been encoded to speech parameters before transmission via a transmission channel. It allows detection at the receiving end of corrupted signal parameters due to adverse channel conditions. The method comprises estimations of the signal quality and a statistic study of the evolution of the signal parameters so as to derive an indication that the parameter is probably corrupted. A first signal quality estimation is performed. It may be e.g. an estimation of the error probability within the most important bits of the frame. A second signal quality estimation is performed. It may be e.g. an estimation of the error probability within all bits of the frame. Depending on the results of the estimations, the statistic study is performed in order to detect which signal parameters are probably corrupted.

Abstract: The invention relates to a communication receiver provided with a loudspeaker and/or a microphone and means for automatically adapting the volume of the loudspeaker and/or microphone according to the local acoustic environment of the receiver and in particular the degree of confinement of the environment. Confinement detection means are provided and comprise adaptive filtering means for modeling the acoustic channel of the receiver by means of the pulse response of an adaptive filter and calculation and comparison means for calculating a power ratio between a partial power and the total power of said pulse response to compare it with reference values and to derive therefrom an estimation of said degree of confinement. Application: Mobile telephony.

Abstract: The error concealment method improves the signal quality in transmission systems. The method is used for processing speech signals which have been encoded to speech parameters before transmission via a transmission channel. It allows detection at the receiving end of corrupted signal parameters due to adverse channel conditions. The method comprises estimations of the signal quality and a statistic study of the evolution of the signal parameters so as to derive an indication that the parameter is probably corrupted. A first signal quality estimation is performed. It may be e.g. an estimation of the error probability within the most important bits of the frame. A second signal quality estimation is performed. It may be e.g. an estimation of the error probability within all bits of the frame. Depending on the results of the estimations, the statistic study is performed in order to detect which signal parameters are probably corrupted.