Using ATM to carry very low bit-rate mobile voice signals

Nakamura, Hiromitsu; Onuki, M.; Nakajima, A.

doi:10.1109/icupc.1995.497132

Cited by 8 publications

(1 citation statement)

References 2 publications

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“…According to the selected coding mode, therefore, each speech source emits a variable number of packets every 10 ms, as indicated in the VR-CELP specification [13]; in our scenario, we chose a fixed 8-bits packet length so that the maximum packetization delay is 20 ms, even in the case of the lowest bit rate. We also assume that, in order to exploit the output ATM link capacity, in the base station a number of packets carrying voice signals of different calls for the same destination is multiplexed to be conveyed in the same ATM cell payload [15][16].…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of an ATM multiplexer loaded with VBR traffic generated by multimode speech coders

Beritelli

Lombardo

Palazzo

et al. 1999

IEEE J. Select. Areas Commun.

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Multimode coders are able to exploit the different characteristics of the speech waveform and to take into account the different peculiarities of background noise, thus allowing improvements in both signal reconstruction and network offered load. In this context the Variable Rate CELP (VR-CELP) coding, that is, a multimode VBR coding based on the Code Excited Linear Prediction technique, has been introduced in literature and is currently being considered for use in various applications, especially in the third generation UMTS cellular systems. The target of the paper is to introduce an efficient and accurate framework allowing a network designer to analyze the impact of multimode VBR speech coding on the quality of service provided by a wireless/wired ATM network. In order to capture the coder output characteristics, we propose to model a VR-CELP voice source by using a switched batch Bernoulli process (SBBP). More specifically, three models are introduced and compared in terms of accuracy and simplicity in determining network performance. As a result of the comparison, a four-state model has been chosen as the best trade-off. The model is then used to analytically derive the loss probability and the jitter probability density function of an ATM multiplexer loaded by a number of VR-CELP sources. Finally, the proposed paradigm has been assessed in a case study where we demonstrate that, for a given output ATM link capacity and for a number of telecommunication services involving voice transmission, VR-CELP coding performs better than traditional ON-OFF coding.

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Section: Introductionmentioning

confidence: 99%