Title :
A voice transmission quality improvement scheme for personal communication systems-super mute scheme
Author :
Suzuki, Masanobu ; Kubota, Shuji
Author_Institution :
NTT Wireless Syst. Lab., Kanagawa, Japan
Abstract :
To improve the ADPCM voice quality in slow fading channels, this paper proposes the super-mute (S-Mute) scheme by using the probability distribution of ADPCM code without error bits and the error patterns. With consideration of characteristics of voice and channel error patterns, it makes it possible to reduce the code error significantly compared with conventional muting, which has only two replacement code patterns. Furthermore, this paper shows the adaptive replacement of ADPCM code against the grade of burst degradation by applying the channel quality estimation scheme, the ADPCM code detection (ACD) scheme. As a result, when the proposed scheme is employed, the mean opinion score (MOS) improves by 0.6 points compared to the conventional muting scheme
Keywords :
adaptive codes; cellular radio; channel coding; coding errors; differential pulse code modulation; error correction; fading; modulation coding; personal communication networks; probability; speech coding; time-varying channels; voice communication; ACD scheme; ADPCM code; ADPCM code detection; ADPCM voice quality; S-mute; adaptive replacement; burst degradation; channel error; channel quality estimation scheme; code error; error bits; error patterns; mean opinion score; personal communication systems; probability distribution; slow fading channels; super mute scheme; voice transmission quality improvement scheme; Adaptive control; Adaptive signal detection; Codecs; Cyclic redundancy check; Degradation; Error correction codes; Fading; Phase change materials; Probability distribution; Programmable control;
Conference_Titel :
Universal Personal Communications. 1995. Record., 1995 Fourth IEEE International Conference on
Conference_Location :
Tokyo
Print_ISBN :
0-7803-2955-4
DOI :
10.1109/ICUPC.1995.497102
