Noisy channel performance of trellis coded quantization

Abstract

Low delay speech coding at 16 kbits/sec has received a tremendous amount of attention. One recently proposed scheme that offers excellent performance with buffering delays less than 5 msec is Trellis Coded Quantization (TCQ). The primary objective of this thesis is to evaluate the performance of TCQ in the presence of channel errors. When feedback-free encoding circuits are employed, error propagation is not a serious problem. For encoding sampled speech, segmental signal-to-noise ratios in excess of 20 dB are obtained. Performance comparisons are made using a fixed predictor and four different adaptive predictors for both error-free and noisy channels. Informal listening tests reveal that the reconstructed speech is of "near toll quality" and is almost indistinguishable from the original speech.