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研究生:林昌賓
研究生(外文):Chang-Pin Lin
論文名稱:網路電話於無線區域網路環境下之通話品質量測分析
論文名稱(外文):Voice Over IP Quality Measurements for Wireless LAN
指導教授:李啟民李啟民引用關係
指導教授(外文):Chi-Min Li
學位類別:碩士
校院名稱:國立臺灣海洋大學
系所名稱:通訊與導航工程系
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2009
畢業學年度:97
語文別:中文
論文頁數:109
中文關鍵詞:網路電話無線區域網路封包延遲封包遺失抖動率
外文關鍵詞:MIMOQOSMOSR-FactorPQLLQ
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網路電話(Voice over IP, VoIP)的應用隨著網際網路的普及越來越廣泛,尤其是結合企業內部網路通訊系統應用最為普遍;無線區域網路(Wireless Local Area Network, WLAN)的傳輸速率(Data Rate)隨著調變技術改良及採用多重輸入與多重輸出天線技術(Multiple Input Multiple Output, MIMO)而快速提升;然而,如何確保語音封包與其它資料於同一傳輸平台同時間傳送時的品質是最大的問題。影響VoIP品質的主要因素有封包遺失(Packet Loss)、封包延遲(Packet Delay)及抖動率(Jitter)等。
本研究以實際建置兩組實驗環境及四種量測架構,將VoIP系統應用於有線及無線網路混合環境下,依據ITU-T對語音品質之標準E模型(E-Model)和平均意見得分(Mean Opinion Score, MOS)來測量VoIP語音品質之等級,分析VoIP於不同WLAN系統環境下之效能,並以實作應用IP網路之低延遲佇列(Low Latency Queuing , LLQ)機制提供確保VoIP 服務品質QOS (Quality Of Service)建議架構。
Voice over IP becomes more and more popular due to the widespread use of the internet. Besides, Wireless Local Area Network can achieve higher speed via using the multiple input multiple output technique. However, it is an important issue to guarantee the Quality of Service of the VoIP through the internet. Three major factors that influence the Quality of Service; i.e., Packet Loss, Packet Delay and Jitter.
The purpose of this study is to measure the QoS of the VoIP in a hybrid wireline and wireless communication environment according to the E-Model and MOS. The influences of these three factors to the QoS are also investigate. Meanwhile, the QoS measurement of a LLQ QoS scheme is also given in the study.
摘要 V
Abstract VI
圖目錄 IX
表目錄 XII
第一章 緒論 1
1.1 前言……………………………………………..………………………… 1
1.2 研究動機與目的 2
1.3 各章內容概要 4
第二章 背景及相關研究 5
2.1 IEEE 802.11之制定標準簡介 5
2.1.1 無線區域網路的基本架構 6
2.1.2 802.11b 7
2.1.3 802.11a 8
2.1.4 802.11g 8
2.1.5 802.11n ( Draft 2.0 ) 9
2.2 VoIP的基本架構原理 10
2.2.1 H.323簡介 10
2.2.2 SIP簡介 12
2.2.3 語音封包壓縮/解壓縮格式 ( Coder/Decoder, CODEC ) 15
2.2.4 網路電話頻寬之計算 17
2.2.5 即時傳輸協定( Real-Time Transport Protocol, RTP ) 18
2.3 影響VoIP品質之因素 21
2.3.1 封包延遲 ( Packet Delay ) 21
2.3.2 封包遺失 ( Packet Loss ) 23
2.3.3 抖動率 (Jitter) 24
2.4 VoIP品質量測方法 25
2.4.1 平均意見得分(Mean Opinion Score, MOS) 26
2.4.2 E-模型 (E-Model) 27
2.5 網路壅塞管理機制 30
2.5.1 類別基礎的加權公平佇列(Class Base Weighted Faire Queue, CBWFQ) 31
2.5.2 優先佇列(Priority Queue, PQ) 32
2.5.3 低延遲佇列(Low Latency Queue, LLQ) 33
第三章 測量的方法及架構 34
3.1 實際量測環境 34
3.1.1 環境 (一) 34
3.1.2 環境 (二) 38
3.2 實驗設備及量測的工具 42
3.2.1 Cisco Aironet 1250 Access Point 42
3.2.2 D_Link DWA-645無線網卡 43
3.2.3 訊舟無線基地台 EDIMAX Access Point BR6204 44
3.2.4 Cisco Router 1841 45
3.2.5 OCTTEL ITG MS-2040 46
3.2.6 IxChariot 5.4 47
3.2.7 Network Stumbler 48
3.2.8 VQManager 49
3.2.9 Wireshark 50
第四章 實驗方法與結果分析 51
4.1 實驗方法重點說明 51
4.2 實驗(一)量測方法與結果分析 53
4.2.1 (A-1)各種無線區域網路系統之傳輸效能比較 54
4.2.2 (A-2)AP使用不同天線數之Data Rate實際量測 58
4.2.2 (A-3)不同無線區域網路系統於接收端移動下之效能比較 61
4.2.4 (A-4)無線區域網路系統之頻寬共享特性量測 63
4.2.5 (B-1)語音封包壓縮格式與網路電話品質之影響 65
4.2.6 (B-2)封包延遲(Delay)對於VoIP語音品質影響 66
4.2.7 (B-3)測量抖動率(Jitter)對於VoIP語音品質的影響 69
4.2.8 (B-4)VoIP於不同無線區域網路系統之容量評估 71
4.3 實驗(二) (三) (四)量測方法及結果分析 72
4.3.1 實驗(二)於無線區域網路下之QOS機制量測 72
4.3.2 實驗(三)於無線及有線區域網路混合環境下之QOS機制量 測.. 80
4.3.3 實驗(四)透過廣域網路連結兩不同無線區域網路之QOS機制量測 85
第五章 結論與建議 92
參考文獻 94
[1] 丁定國, 無線網路語音服務經營策略之研究. 國立臺灣大學管理學院碩士在職專班高階公共管理組碩士論文, 2007年7月.
[2] ITU-T Recommendation P.800, “Methods for objective and subjective assessment of quality”, Mar 2003.
[3] ITU-T Recommendation G.107, “The E-model, a computational model for use in transmission planning”, Mar 2005.
[4] Wi-Fi Alliance,
http://www.wi-fi.org
[5] IEEE Std. 802.11n/D2.00, “IEEE Standard for information Technology - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Enhancements for Higher Throughput”, February 2007.
[6] IEEE Std. 802.11-1999, “IEEE Standard for information Technology - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, Reference number ISO/IEC 8802-11:1999(E), IEEE Std. 802.11, 1999 edition”, 1999.
[7] IEEE Std. 802.11a-1999, “IEEE Standard for information Technology - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, High-speed Physical Layer in the 5 GHz Band,” 1999.




[8] IEEE Std 802.11b-1999, “IEEE Standard for information Technology - Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications , Higher-Speed Physical Layer Extension in the 2.4 GHz Band”, 2000.
[9] IEEE Std 802.11g-2003, “IEEE Standard for Information Technology – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications – Amendment 4: Further Higher Data Rate Extension in the 2.4 GHz Band”, Jun 2003.
[10] ITU-T Recommendation H.323, “Packet-based multimedia communications systems”,ITU-T, June 2006.
[11] J. Rosenberg, H. Schulzrine, G. Camarillo, A.Johnston, J. Peterson, R. Sparks, M. Handley, E.Schooler,”SIP:Session Initial Protocol”, RFC3261, IETF, Jun.2002.
[12] ITU-T Recommendation G.729, ”Coding of Speech at 8Kbit/s using Conjugate-structure Algebraic-Code-Excited Linear-Prediction” , ITU-T, Mar. 1996.
[13] B. Goode, ”Voice over Internet Protocol (VoIP)”, in Proc. the IEEE, vol.90, no.9, Sep. 2002, Page(s):1495~1517.
[14] Cisco System. 2005. Voice Over IP - Per Call Bandwidth Consumption, http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.shtml
[15] H. Schulzrinne, S. Casner, R. Frederick , V.Jacobson,“ RTP: A Transport Protocol for Real-Time Applications,” RFC 1889, IETF,Jan.1996.
[16] Wireshark, Vesion 1.08, http://www.wireshark.org/download.html
[17] ITU-T Recommendation G.114, “One-wayTransmission time”, May 2003;
[18] ITU-T Recommendation G.1010, “End-user multimedia QoS categories”,November 2001.
[19] Cisco System, IP SLAs - Analyzing Service Levels Using the
VoIP UDP Jitter Operation, https://www.cisco.com/en/US/docs/ios/12_4/ip_sla/configuration/guide/hsvoipj.pdf
[20] Floriano De Rango, Mauro Tropea, Peppino Fazio, Salvatore Marano,” Overview on VoIP: Subjective and Objective Measurement Methods”, IJCSNS International Journal of Computer Science and Network Security, VOL.6 No.1B, January 2006, Paper(s):140-153.
[21] Brunonas Dekeris, Tomas Adomkus, Aurelijus Budnikas,”Analysis of QoS Assurance Using Weighted Fair Queueing (WFQ) Scheduling Discipline with Low Latency Queue (LLQ)”, Int. Conf. Information Technology Interfaces ITI 2006 , June 19-22, 2006, Paper(s):507-512.
[22] Cisco System, Access Point 1252, http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps6973/ps8382/product_data_sheet0900aecd806b7c5c.html
[23] D-Link System, DWA-645, http://www.dlink.com/products/?pid=532
[24] EDIMAX System, Access Point BR-6204, http://www.edimax.com/tw/support_detail.php
[25] Cisco System, 1841 Router, http://www.cisco.com/en/US/products/ps5875/index.html
[26] OCTTEL Communication System. MS-2040, http://www.trade-taiwan.org/WebSiteTemp/a4.asp
[27] IxChariot System. IxChariot 5.4, http://www.ixiacom.com/
[28] NetStumber, http://www.netstumbler.com/
[29] ZOHO Corporation . VQmanager, http://www.zohocorp.com/
[30] Cisco System. 2008 . Cisco and Intel: Collaborative 802.11n Leadership andTesting, http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns767/white_paper_c11-492743.html
[31] IEEE Standard, “802.11e Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. Amendment: Medium Access Control (MAC) Quality of Service (QoS) Enhancements,” Jan 2005.
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