26.1913GPPAdaptive Multi-Rate - Wideband (AMR-WB) speech codecError concealment of erroneous or lost framesRelease 17Speech codec speech processing functionsTS
The purpose of the error concealment procedure is to conceal the effect of erroneous/lost AMR-WB speech frames. The purpose of muting the output in the case of several erroneous/lost frames is to indicate the breakdown of the channel to the user and to avoid generating possible annoying sounds as a result from the error concealment procedure.
The network shall indicate erroneous/lost speech or lost SID frames by setting the RX_TYPE values  to SPEECH_BAD, SID_BAD or SPEECH_LOST. If these flags are set, the speech decoder shall perform parameter substitution to conceal errors.
The example solution provided in paragraph 6 apply only to bad frame handling on a complete speech frame basis. Sub-frame based error concealment may be derived using similar methods.