Impact of new digital compression on the perceptual quality of speech transmitted via fixed satellite link

In this paper, we present the results of our theoretical, computer simulation and experimental investigations of correlation between the speech quality as per ITU-T proposed PSQM method, and various (standard) coding algorithms, data transmission speeds and satellite link error performance levels. We considered both waveform encoders and vo(ice)coders, and specifically, backward predictive and CELP encoders, in contrast to classic PCM encoders, showing that, for satellite transmission channels, the coding efficiency and transmission speed are not the only and ultimate code selection criteria, but also the quality of the received signal, code delay, susceptibility to interferences and transmission errors. Some elsewhere standard coding techniques (e.g. CELP) have been shown to be inadequate for the transmission via satellite channels.