인터넷 전화의 사용자 관점 품질 최적화를 위한 강건 설계 기법 연구 = Robust Design Methodology for Optimizing Perceived QoS of VoIP

다국어 초록 (Multilingual Abstract)

During the past few years, design of experiments (DOE) has been gaining acceptance in the telecommunications research community as a mean for designing and analyzing experiments economically and efficiently. In addition, the need for introducing a systematic robust design methodology (i.e., one of the most popular DOE methodologies) to network simulations has been increasing. In this paper, we present an architecture of voice over IP (VoIP) application and the E-Model for calculating the perceived quality of service (QoS). Then, we apply the Taguchi robust design methodology to optimize the perceived QoS of VoIP application, and describe the detailed step-by-step procedures. We have used ns-2 simulator to collect experimental data in which the SN ratio, a robustness measure, is analyzed to determine an optimal design condition. The analysis shows that "initial delay time in playout buffer" is a major control factor for ensuring robust behaviors of the perceived QoS of VoIP. Finally, we verify the proposed optimal design condition using a confirmation experiment.

목차 (Table of Contents)

• 1. 서론
• 2. 연구 배경
• 3. 실험 설계 및 데이터 수집 단계
• 4. 분석 및 검증 단계
• 5. 결론
• 참고문헌

참고문헌 (Reference)

1 Cole, R. G., "Voice over IP performance monitoring" 31 (31): 9-24, 2001

2 Bacioccola, C., "User-level performance evaluation of VoIP using ns-2" 2007

3 ITU-T Recommendation G.107., "The E-model"

4 Taguchi, G., "Taguchi Methods : Research and Development" ASI Press : Dearborn 1992

5 Taguchi, G., "Taguchi Methods : Design of Experiments" ASI Press : Dearborn 1993

6 Gendy, M. E., "Statistical characterization for per-hop QoS" 21-40, 2003

7 Yoon, H. S., "Robust design of communication systems : The case of expedited forwarding of voice traffic in differentiated services networks" 20 : 1131-1154, 2007

8 Myers, R. H., "Response surface alternatives to the Taguchi parameter design approach" 46 (46): 131-139, 1992

9 Myers, R. H., "Response Surface Methodology : Process and Product Optimization Using Designed Experiments" Wiley-Interscience 1995

10 Phadke, M. S., "Quality Engineering Using Robust Design" Englewood Cliffs 1989

11 Atzori, L., "Playout buffering in IP telephony : a survey discussing problems and approaches" 8 (8): 36-46, 2006

12 NS-2., "NS-2"

13 Liao, W., "Mobile Internet telephony protocol : an application layer protocol for mobile Internet telephony services" 99 (99): 339-343, 1999

14 Taguchi, G., "Introduction to Quality Engineering" Asia Productivity Organization 1986

15 Heidemann, J., "Expanding confidence in network simulations" 15 (15): 58-63, 2001

16 Ziviani, A., "Evaluating the expedited forwarding of voice traffic in a differentiated services network" 15 : 799-813, 2002

17 Taguchi, G., "Design of Experiments Using Orthogonal Tables" Union of Japanese Scientists and Engineers 1959

18 Montgomery, D. C., "Design and Analysis of Experiments, 6th ed" Wiley 2005

19 Blake, S., "An architecture for differentiated services"