Title :
A codec control method and its mounting technique for low bit-rate voice communication systems
Author :
Yasuda, Sadayda ; Kitamura, Yoshihiro
Author_Institution :
NTT Network Service Syst. Labs., Tokyo, Japan
Abstract :
A codec control method for low bit-rate multi-channel communication systems has been developed. By controlling multiple-channel codecs to output encoded voice packets with constant intervals, we reduced the packet-assembly delay and the delay variation. Based on this method, we also developed a channel assignment scheme when the number of channels in use is less than the number available. Moreover, in order to reduce the board size, we developed a high-density mounting technique, which can integrate 32 codecs and 32 echo-cancelers in half the area of a PCI expansion board. We applied these techniques to a prototype low bit-rate voice-over-ATM communication system, and confirmed that the cell-loss rate was reduced to 1/10, so 8% more channels are available than without using the control method (at 256-kbps transfer bandwidth)
Keywords :
asynchronous transfer mode; delays; modules; packet switching; speech codecs; telecommunication control; voice communication; 256 kbit/s; PCI expansion board; board size reduction; cell-loss rate; channel assignment; codec control method; constant intervals; delay variation; echo-cancelers; high-density mounting technique; low bit-rate voice communication systems; modules; multichannel communication systems; multiple-channel codecs; packet-assembly delay; transfer bandwidth; voice packets; voice-over-ATM communication system; Assembly; Asynchronous transfer mode; Bandwidth; Codecs; Communication system control; Control systems; Costs; Delay effects; Echo cancellers; Timing;
Conference_Titel :
Global Telecommunications Conference, 1998. GLOBECOM 1998. The Bridge to Global Integration. IEEE
Conference_Location :
Sydney,NSW
Print_ISBN :
0-7803-4984-9
DOI :
10.1109/GLOCOM.1998.776481
