臺灣博碩士論文加值系統

應用RTP (Real Time Protocol) 做為通訊協定來傳輸Multimedia，並藉由RTP中之RTCP (Real Time Control Protocol) 來針對網路狀況進行回授控制；本文對於目前3G通訊系統的QoS設計一套符合Real-time Video傳輸的streaming control 機制 以及在有線網路端提供Transcoding-enabled Caching algorithm來分擔streaming server要做transcoding的負荷，在data flow傳輸時加入Double Feedback Streaming Agent (DFSA)來針對多餘的頻寬進行更有效率的傳送Feedback控制。

Double Feedback Streaming Agent (DFSA)的機制是讓RTP在3G的環境中，保有其特性，並進一步分別針對3G Core Network或Radio所發生的問題做改善。並利用Proxy cache機制配置在網路的edge端用來降低流量以及延遲，此機制會取得DFSA所提供目前client端的connection speed和device capability等資訊來提供media transcodeing，透過caching algorithm執行後，重新將transcoding media cache起來使系統的負擔更為降低，而使用者也因此可以獲得更高且穩定的服務品質。

我們針對所提出的網路環境架構，利用NS2來採取對RTCP中的loss rate 和jitter各別做分析，提供目前3G環境中有關streaming media傳輸的QoS議題，並做一結論。

It is known that RTP (Real Time transport Protocol) is a communication protocol can be used to transmit multimedia with feedback control about network status offered by RTCP (Real Time Control Protocol). In this article, we design a Real-Time video streaming control mechanism for QoS of 3G communication system, and we propose a transcoding-enabled caching algorithm to share the transcoded load of streaming server, we adapt Double Feedback Streaming Agent (DFSA) in transport data flow to transmitting more efficiently feedback control towards network under-utilization bandwidth.

DFSA mechanism is one of the ways to use RTP in 3G environment and keep its property. Furthermore, DFSA respectively towards the problems occurred to 3G core network or radio to modify. We take advantage of proxy cache mechanism which places in the edge of network to reduce flow and delay. This mechanism will obtain the connection speed and device capability of presently client’s information offered by DFSA. By the way of implementing caching algorithm, we get the new transcoding media bit-rate and cache it to decrease the system load, therefore we can acquire higher and more stable quality of service.

We toward our architecture, we use NS2 to respectively analyze the loss rate and jitter in RTCP report. We address related issues of transmitting streaming media in recently 3G environment and draw a conclusion.

目錄
論文摘要 3
Abstract 4
圖表目錄 6
第一章、緒論 7
1.1 簡介 7
1.2 研究動機 7
1.3研究目的 8
1.4 論文架構 8
第二章、背景知識及相關研究 9
2.1 UMTS系統架構 9
2.2 相關協定與技術 11
2.2.1 RTP (Real Time transport Protocol) 11
2.2.2 RTCP (Real Time transport Control Protocol) 13
2.3 Streaming Agent for Wired Network/Wireless Link Rate-Mismatch Environment 15
2.3.1 End-to-end Approach 15
2.3.2 RTP Monitoring Agent 15
2.4 Double Feedback Streaming Agent for Real-Time Delivery of Media Over 3G Wireless Networks 18
2.4.1 FEC decoder & encoder 18
2.4.2 DFSA Shaping Point 19
2.4.3 Double Feedback Generator 19
第三章、問題描述與研究方法 20
3.1現行網路與3G通訊網路的頻寬差異 20
3.2 Streaming Media Caching with Transcoding-Enabled Proxies 22
3.3理論架構 27
第四章、模擬實驗與研究分析 29
4.1模擬軟體-NS2 29
4.2模擬環境設定 31
4.3模擬結果分析 33
第五章、結論與未來展望 41
參考文獻 42

圖表目錄
圖 2.1 UMTS 系統架構圖 9
圖 2.2 RTP header 11
圖 2.3 RTCP header 13
圖 2.4 RTP Monitoring Agent 16
圖 2.5 Double Feedback Streaming Agent 18
圖 3.1 R1* > R2* 20
圖 3.2 TeC系統和元件 22
圖 3.3 理論架構 27
圖 4.1 C++與OTcL的比較 29
圖 4.2 NS架構 30
圖 4.3 NS2模擬架構圖 31
圖 4.4模擬環境設定 31
圖 4.5 Simulation Case 32
圖 4.6 Case 2M (以設定數據進行模擬) 33
圖 4.7 Case 384k : bandwidth 384k bit/s 34
圖 4.8 Case 192k : bandwidth 192k bit/s 35
圖 4.9 Case error_rate : radio link的error rate 為5 ％ 36
圖 4.10 Case TeC_96k : TeCbit rate版本96k bit/s 37
圖 4.11 Case TeC_64k : TeCbit rate版本64k bit/s 38
圖 4.12 Delay Jitter分佈圖 39
圖 4.13 Loss rate統計圖 39

[1]Shin-Ming Cheng, Chai-Hien Gan, Phone Lin and Guan-Hua Tu, “Key Issues and Technologies for UMTS High Speed Downlink Packet Access,” Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Bulletin of the College of Engineering, N.T.U, No.90, February 2004, pp. 57-63.

[2]T. Yoshimura, Gene Cheung and Wai-tian Tan, ”Streaming Agent For Wired Network/ Wireless Link Rate-Mismatch Environment,” Multimedia Signal Processing , 2002 IEEE Workshop on, 9-11 Dec. 2002, Page(s):388 – 391.

[3]Henning Schulzrinne, Stephen L. Casner, Ron Frederick, Van Jacobson, “RTP: A Transport Protocol for Real-Time Applications,” RFC 3550 Internet Engineering Task Force, July 2003.

[4] J. Rosenberg and H. Schulzrinne, ”An RTP Payload Format for Generic Forward Error Correction,” RFC2733, Internet Engineering Task Force, December 1999.

[5]鄭同伯，資策會網路多媒體研究所3G團隊, ”3G帶領行動通訊新未來,” 資訊尖兵雜誌 出版, 2004.

[6]G . Cheung and T . Yoshimura , ”Streaming Agent : A Network Proxy for Media Streaming in 3G Wireless Networks,” in Packet Video Workshop , 2002.



[7]T. Yoshimura , T. Ohya , T. Kawahara and M. Etoh, ”Rate and Robustness Control with RTP Monitoring Agent for Mobile Multimedia Streaming,” in IEEE Int. Conf. Communications, vol. 4, New York, Apr. 28–May 2, 2002, pp. 2513–2517.

[8]Gene Cheung, Wai-Tian Tan and Takeshi Yoshimura, ”Double Feedback Streaming Agent for Real-Time Delivery of Media Over 3G Wireless Networks,” IEEE Transactions on Multimedia, VOL. 6, NO. 2, APRIL 2004.

[9]Bo Shen, Sung-Ju Lee, and Sujoy Basu, Hewlett-Packard Laboratories , ”Streaming Media Caching with Transcoding-Enabled Proxies, ” Multimedia, IEEE Transactions on Volume 6, Issue 2, April 2004.

[10]陳文賢, 薛伊良, 程鈞鴻, 吳紹康, ”A RTP Multimedia mechanism for 3G RRM－Rate Update Algorithm,” Symposium on Digital Life and Internet Technologies, Jun 2004.

[11]NS2 , available from http://www.isi.edu/nsnam/ns/