Publicações > Artigos em Revistas Internacionais

Accurate resource estimation for generalized VoIP sources

Estepa, A.; Estepa, R.; Pacheco, António

Telecommunication Systems, 39(1) (2008), 37-50

Current voice codecs like G.729, G.723.1 or AMR can generate short background descriptors (SID) frames during voice inactivity periods for Comfort Noise Generation (CNG). This feature alters the classical on-off traffic pattern typically used to model the traffic generated by codecs with a Silence Suppression scheme. Therefore the CNG feature leads to severe inaccuracies in the dimensioning analysis done through traditional models based on multiplexing on-off sources like MMPP or fluid model.

In this paper, we focus on the VoIP dimensioning issue. First, we define the traffic pattern generated by those codecs that include CNG (generalized VoIP sources). Second, we extend the traditional MMPP and fluid analytical models to multiplex our generalized VoIP sources and propose a simple but efficient dimensioning algorithm. Results are validated by simulations fed by VoIP traces and demonstrate a significant improvement in accuracy with respect to current on-off based approaches