Standardization activity in ITU of extending 16-kbit/s LD-CELP for personal communication systems

Author

Hayashi, Shinji ; Ogawa, Mineyoshi

Author_Institution

NTT Human Interface Labs., Tokyo, Japan

fYear

1995

Firstpage

813

Lastpage

817

Abstract

This paper introduces the standardization activity in ITU-T (International Telecommunication Union, Telecommunication Standardization Sector) of extending 16-kbit/s LD-CELP (low-delay code-excited linear-predictive) speech coding for personal communication systems. ITU-T Recommendation G.728 (LD-CELP) provides toll quality at 16 kbit/s with very low algorithmic delay time (0.625 ms). However, its quality significantly falls under conditions when-the received codewords are lost for 10 to 100 ms that tend to occur in radio channels. The extension of LD-CELP consists of the decoder modification proposed by AT&T that conceals the erasure of channel frames. Subjective test results using Japanese speech shows fairly good quality with this concealment for frame-erasure conditions

Keywords

decoding; delays; linear predictive coding; personal communication networks; speech coding; standardisation; 0.625 ms; 10 to 100 ms; 16 kbit/s; AT&T; ITU; ITU-T Recommendation G.728; International Telecommunication Union; Japanese speech; LD-CELP; Telecommunication Standardization Sector; algorithmic delay time; channel frames erasure concealment; decoder modification; low-delay code-excited linear-predictive speech coding; personal communication systems; radio channels; received codewords; speech coding; standardization; subjective test results; toll quality; Circuits; Decoding; Delay effects; Filters; Multiplexing equipment; Robustness; Signal synthesis; Speech coding; Speech synthesis; Standardization;

fLanguage

English

Publisher

ieee

Conference_Titel

Universal Personal Communications. 1995. Record., 1995 Fourth IEEE International Conference on

Conference_Location

Tokyo

Print_ISBN

0-7803-2955-4

Type

conf

DOI

10.1109/ICUPC.1995.497122

Filename

497122