一個有效的遺失率估算法之設計與實驗

Design and Experiment of an Effective Loss Rate Estimation Method

陳俊麟(Chin-Ling Chen) ； 李建用(Jian-Yong Lee)

《資訊管理學報》 14卷3期 (2007/07) Pp. 229-266

https://doi.org/10.6382/JIM.200707.0229

摘要

本文假設在傳送端有一個可支援兩個相同內容但不同語音音質檔案（PCM和GSM）的雙模式編碼器。傳送端根據以變動框架長度為基礎之遺失率估算法，來估算目前網路上封包遺失的狀況，並以此作為切換高低音質檔案的依據。此演算法可過濾短期突發交通，並呈現長期交通之趨勢。除具有穩定與敏捷的特性外，此演算法亦能避免音質切換過度頻繁。

關鍵字

遺失率 ； 交通量測 ； RTP ； RTCP

並列摘要

In this paper, we assume that the sender supports a two-mode codec with two audio sample files (PCM and GSM). The sender tracks the packet loss status according to the algorithm-loss rate estimation based on variable frame size and switches two audio sample files in accordance with packet loss status. The proposed algorithm smoothes short term variations in loss rates, while responds quickly to real changes in the loss rate of the traffic. The ability of the algorithm is qualified by the agility, stability and avoidance of frequent switching for two sample files.

並列關鍵字

loss rate ； traffic estimation ； RTP ； RTCP

參考文獻

H. Schulzrinne,S. Casner,R. Frederick,V. Jacobson(2003).A Transport Protocol for Real-Time Applications.(RFC 3550, Internet Engineering Task Force).

G. Huston(2000).Next Steps for the IP QoS architecture.(RFC 2990, Internet Engineering Task Force).

ITU-T draft,P.VTQ.The assessment of voice transmission quality from protocol analysis information in IP networks.

A. Takahashi,H. Yoshino,N. Kitawaki(2004).Perceptual QoS assessment technologies for VoIP.(IEEE communications magazine).

ITU-T Recommendation P.862(2001).Perceptual evaluation of speech quality (PESQ), an objective method for end-to-end speech quality assessment of narrowband telephone networks and speech codes.