A Discontinuous Transmission Method for LPC Speech Codec

Abstract:

In order to improve the utilization of transmission bandwidth in voice communication, this paper proposes a discontinuous transmission method for LPC speech codec. Firstly, by using the algorithm of voice activity detection (VAD), the received signal is divided into voice frame and mute frame. Transitional frame is introduced when the voice frame is converted to mute frame. Then voice frames and transitional frames are encoded at a normal rate, but mute frames are encoded into silence description (SID) frame at a lower rate, which is sent by a method of discontinuous transmission mode. The transmission frequency of SID frame is adjusted automatically according to the fluctuation of characteristic parameters of background noise in mute frames. Finally, the method is applied to the simulation in the MELP vocoder, and the results show that this method has better adaptability in the transmission of mute signal and the synthesized background noise presents good comfort and continuity in the auditory perception.

• Periodical: Applied Mechanics and Materials (Volumes 644-650)
• Pages: 4346-4350
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.644-650.4346
• Online since: September 2014
• Authors: Hong En Xie*, Qiang Li, Qin Jun Shu
• Keywords: Discontinuous Transmission, LPC Speech Codec, Silence Description, Voice Activity Detection

References

[1] 3GPP TS 26. 093 version 11. 0. 0, Adaptive Multi-Rate (AMR)speech codec; Source controlled rate operation(Release 11). (2012).

[2] Benyassine A, Shlomot E, Su H Y, et al: ITU-T Recommendation G. 729 Annex B: a silence compression scheme for use with G. 729 optimized for V. 70 digital simultaneous voice and data applications. Communications Magazine, IEEE, Vol. 35 (1997).

DOI: 10.1109/35.620527

[3] Liang Z, Ying-Chun G, Bian Z Z, et al: Voice activity detection algorithm improvement in adaptive multi-rate speech coding of 3GPP, Wireless Communications, Networking and Mobile Computing, 2005. Proceedings. 2005 International Conference on. Piscataway, N. J: IEEE Press, 2005: p.1257.

DOI: 10.1109/wcnm.2005.1544283

[4] Wang T, Koishida K, Cuperman V, et al: A 1200/2400 bps coding suite based on MELP, Speech Coding, 2002, IEEE Workshop Proceedings. Piscataway, N. J: IEEE Press, 2002, p.90.

DOI: 10.1109/scw.2002.1215734

[5] Beerends J G, van Wijngaarden S, van Buuren R: Extension of ITU-T recommendation P. 862 PESQ towards measuring speech intelligibility with vocoders. TNO TELECOM DELFT (NETHERLANDS), (2005).