Channel coding considerations for digital speech encoded by linear prediction

We are concerned with the protection of speech parameters, produced by a linear predictor, when they are transmitted through a typical communications channel. An analysis of the complete system yields a lower bound to the overall mean-square error. These results isolate the role that channel coding plays in the total system performance. Our goal is to motivate the selection of a more sensible criterion for designing channel coding in such systems. We demonstrate that the mean-square error criterion used on a channel basis is such a choice and that there are reasonable design procedures for employing block codes in this fashion. This type of coding can be applied not only to whole individual speech coefficients but to various groups of positions. Finally the implementation of the corresponding decoder is examined from the viewpoint of generalized bandpass filtering.