The following information was submitted:
Transactions: WSEAS TRANSACTIONS ON COMMUNICATIONS
Transactions ID Number: 29-759
Full Name: Leopoldo Estrada
Position: Ph.D. Candidate
Age: ON
Sex: Male
Address: Cientifica Ave. 1145 Zapopan, Jalisco, Mexico 45015
Country: MEXICO
Tel: 37773600
Tel prefix: 5233
Fax: 37773609
E-mail address: lestrada@gdl.cinvestav.mx
Other E-mails:
Title of the Paper: Analytical Description of a Parameter-based Optimization of the Quality of Service for VoIP Communications
Authors as they appear in the Paper: Leopoldo Estrada, Deni Torres, Homero Toral
Email addresses of all the authors: lestrada@gdl.cinvestav.mx,dtorres@gdl.cinvestav.mx,htoral@gdl.cinvestav.mx
Number of paper pages: 11
Abstract: In this work, the perceived quality of VoIP communications is studied. The distributions of the number of consecutive received and lost packets, respectively named gap and burst, of a VoIP communication are modeled with discrete two-state and four-state Markov chains. Algorithms for estimating the transition probabilities between states and from these, the packet loss rate and the respective gap and burst length distributions, are described. Through a study of monitored VoIP calls, it is shown that these models can adequately represent the geometric-type decay of these distributions and that although two-state model performs well for homogeneous losses, for non-homogeneous losses the four-state model fits better. An analysis of the performance of a packet-level FEC scheme, based on N-packet redundancy, is presented. The perceived packet loss rate that results of applying this correction scheme is quantified. For the studied measurements, 1-packet redundancy is suff!
icient to decrease the perceived loss rate below 1%. Also, the impairments of the perceived quality of voice after the FEC technique and a de-jitter buffer is quantified. The resulting equations can be used to optimize the adjust parameters of the VoIP call, e.g., level of redundancy, type of codec used and de-jitter buffer size. The proposed methodology can be extended if other types of improvements are included.
Keywords: VoIP, Packet loss distribution, Packet reception distribution, N-packet FEC, QoS.
EXTENSION of the file: .pdf
Special (Invited) Session: Analytical Investigation of the Performance of Packet-level FEC Techniques in VoIP Communications
Organizer of the Session: 617-438
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