Simulation Analysis of the Waiting Time Distribution of a Packetized Voice Concentrator

Julio SEGUEL  Yoshiaki TANAKA  Minoru AKIYAMA 

Publication
IEICE TRANSACTIONS (1976-1990)  Vol.E65  No.2  pp.115-122
Publication Date: 1982/02/20
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Switching Systems
Keyword: 


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Summary: 
A store and fordward speech interpolation telephonic concentrator system is introduced. This paper presents first the system, describes its main parts and components and using typical parameters the probable system operation is outlined. Following, a study on capacity and delay of transmission of each voice packet is done by supposing that a M/D/1 model can be applied to the system. As voice has special characteristics and packets don't arrive randomly as supposed in the M/D/1 model, an analysis using a computer simulation is done. The source generating speech is closely matched with human voice by using a model with good resolution specially for small pauses of talkers during the active generation of speech. Using this source, simulations representing 120 or 180 sec. of actual time are done. As its results are different of those predicted by the M/D/1 model, the capacity of the system is forecasted again through examples. To increase even more the capacity without impairing the frozen out fraction of the speech or increasing the delay of each packed, a different method to decrease congestion in those short moments of high arrival rate of packets is intended. This method consist in to transmit from each voice sample only 7 bits during the high congestion moments, creating new capacity by shortening packets. Results of parameters obtained by simulation and probable capacity of the system are again shown.