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研究生： 張志豪
Chih-hao Chang
論文名稱： UMTS 頻道交換機制之研究
Research on Channel Switching Mechanisms in UMTS
指導教授： 陳秋華
Chyou-hwa Chen
口試委員: 邱舉明
Ge-Ming Chiu
馮輝文
Huei-Wen Ferng
學位類別： 碩士
Master
系所名稱： 電資學院 - 資訊工程系
Department of Computer Science and Information Engineering
論文出版年： 2006
畢業學年度： 94
語文別： 英文
論文頁數： 98
中文關鍵詞： 頻道交換 、UMTS 、TCP 感知
外文關鍵詞： Channel Switching, UMTS, TCP Sensitive
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  •  上一筆

    • 第三代行動網路，如 UMTS，包含兩種頻道類型：公用頻道與專屬頻道。公用頻道可以被所有在此基地台覆蓋範圍下的所有手機共享，但它們的頻寬非常小，只適合少量資料的傳輸，如簡訊。專屬頻道通常擁有較高的頻寬，而且其頻寬可依據傳輸條件及應用程式的品質要求來做調整，因此專屬頻道適合傳輸較大量的資料，如網頁瀏覽或檔案傳輸。
    對於 UMTS 系統而言，展頻碼是一個很重要的資源，它的數量是有限的，而較高頻寬頻道所需佔用的展頻碼相較於較少頻寬頻道要來得多。因此當展頻碼不需使用或不需使用到那麼多的時候，適時的釋放資源，將使得網路資源的使用更有效率，並且允許需要展頻碼的使用者可以使用。
    頻道交換機制是一種動態交換不同型態傳輸頻道的技術，如在公用頻道與專屬頻道間切換。在以往的研究題目當中，頻道交換通常採取的方式是以臨界點為基準的量測法，藉由量測 RLC 佇列大小來判斷是否進行頻道交換。在本文中，我們提出了一種以量測實際傳輸協定狀況，作為交換基礎的演算法。在模擬結果中，我們發現這個演算法可以動態適應 TCP 的連線狀態，並且使得網路資源得以更有效率的被利用。

    In modern 3rd generation (3G) wireless systems such as UMTS, there are two types of channels: common channels and dedicated channels. Common channels are available to all users in the cell, but their bandwidths are very small. They are good for transmit small amount of data, such as short messages. Dedicated channels have more bandwidths and are able to change their transmission rate depending on the transmission conditions and application needs. Therefore, dedicated channels are suitable for transmit large amount of data, such as web browsing and FTP downloads.
    Spreading codes are valuable resources in UMTS. The number of available codes is limited in a cell. Higher bandwidth channels require more codes than the lower bandwidth ones. The release of dedicated channels when no longer needed ensures the efficient use of the network resources, and allows other users in the cell to use them.
    Channel switching mechanism is the ability to dynamically switch different types of transport channels, such as common channels and dedicated channels, and dynamically change the bandwidths of dedicated channels. In the previous research works, the mechanism is based on a threshold-based measurement of the RLC buffers. In this thesis, we propose a new channel switching algorithm that the switching criteria are determined from the actual conditions of the upper layer protocols, such as TCP. The simulation results show this algorithm is adaptive to TCP’s connection state and the channel resources can be used more efficiently.

    誌謝 I 摘要 II ABSTRACT III TABLE OF CONTENTS V LIST OF FIGURES VII LIST OF TABLES X ABBREVIATIONS XI 1 INTRODUCTION 1 1.1 MOTIVATION 1 1.2 THESIS ORGANIZATION 2 2 RELATED WORKS 3 2.1 THE UMTS SYSTEMS 3 2.1.1 UMTS Introduction 3 2.1.2 UTRAN Architecture 4 2.1.3 The WCDMA Protocol 6 2.1.4 UMTS Transport Channel Switching 17 2.2 TRANSMISSION CONTROL PROTOCOL 24 2.2.1 TCP Background 24 2.2.2 TCP Congestion Control 26 2.2.3 TCP Throughput Model 29 2.2.4 Inferring TCP Characteristics 31 2.2.5 Measuring TCP Loss Rate 33 3 TCP-SENSITIVE CHANNEL SWITCHING ALGORITHM 36 3.1 THE CHANNEL SWITCHING ALGORITHM 36 3.1.1 RLC Structure 36 3.1.2 Two Factors and Their Impacts 37 3.1.3 The Channel Switching Algorithm 43 3.2 THE IMPLEMENTATION 47 3.2.1 Network Topology 47 3.2.2 Node Structures 47 3.2.3 A Channel Switching Add-on for EURANE 50 3.2.4 TCP Monitor 53 3.2.5 Measuring Loss Rate 56 3.2.6 Filtering Spikes in TCP Loss Rate Measurement 56 4 SIMULATION RESULTS 58 4.1 SIMULATION ENVIRONMENT 58 4.2 SIMULATION PARAMETERS 58 4.3 SIMULATION RESULTS 59 4.3.1 Lower Channel Entrance Factor 60 4.3.2 Higher Channel Entrance Factor 63 4.3.3 More Signaling Delay 67 4.3.4 More TCP Loss 70 5 DISCUSSIONS AND CONCLUSIONS 74 5.1 SIGNALING DELAY 74 5.2 CONCLUSION AND FUTURE WORKS 74 5.3 FUTURE WORKS 74 REFERENCES 76

    [1] 3GPP organization, http://www.3gpp.org.
    [2] 3GPP Technical Specification 25.211 V3.0.0, Physical channels and mapping of transport channels onto physical channels (FDD), 3GPP, 1999.
    [3] 3GPP Technical Specification 25.321 V3.0.0, Medium Access Control (MAC) protocol specification, 3GPP, 1999.
    [4] 3GPP Technical Specification 25.322 V3.0.0, Radio Link Control (RLC) protocol specification, 3GPP, 1999.
    [5] 3GPP Technical Specification 25.331 V3.0.0, Radio Resource Control (RRC); Protocol specification, 3GPP, 1999.
    [6] The Network Simulator - ns2, available at http://www.isi.edu/nsnam/ns/.
    [7] X. Dubois, Performance of Different TCP Versions over UMTS Common/Dedicated Channels, 2005.
    [8] S. Floyd, Connections with Multiple Congested Gateways in Packet-Switched Networks Part1: One-way Traffic, ACM Computer Communication Review, 21 (1991), pp. 30-47.
    [9] S. Floyd, M. Handley, J. Padhye and J. Widmer, Equation-based congestion control for unicast applications, SIGCOMM 2000, 2000, pp. 43-56.
    [10] G. Hasegawa, M. Murata and H. Miyahara, Fairness and stability of congestion control mechanisms of TCP, Eighteenth Annual Joint Conference of the IEEE Computer and Communication Societies, 1999, pp. 1329-1336.
    [11] H. Holma and A. Toskala, WCDMA for UMTS: radio access for third generation mobile communications, John Wiley & Sons, Chichester, West Sussex, England; Hoboken, N.J., 2004.
    [12] S. Jaiswal, G. Iannaccone, C. Diot, J. Kurose and D. Towsley, Inferring TCP connection characteristics through passive measurements, In Proceedings of INFOCOM, 2004.
    [13] A. Jehangir, A. Lo, D. Baakman, N. Whillans, I. d. Bruin, F. Brouwer and S. Oosthoek, Enhanced UMTS Radio Access Network Extensions (EURANE) for ns-2, available at http://www.ti-wmc.nl/eurane/, 2006.
    [14] H. Kaaranen, A. Ahtiainen, L. Laitinen, S. Naghian and V. Niemi, UMTS Networks: Architecture, Mobility and Services, John Wiley & Sons, Chichester, West Sussex, England, 2005.
    [15] Y. Ohta, K. Kawahara, T. Ikenaga and Y. Oie, Performance Evaluation of Channel Switching Scheme for Packet Data Transmission in Radio Network Controller, 2002.
    [16] J. Padhye, V. Firoiu, D. Towsley and J. Krusoe, Modeling TCP Throughput: A Simple Model and its Empirical Validation, ACM SIGCOMM '98 conference on Applications, technologies, architectures, and protocols for computer communication, 1998, pp. 303-314.
    [17] B. J. Prabhu, E. Altman, K. Avrachenkov and J. A. Dominguez, A Simulation Study of TCP Performance over UMTS Downlink, Vehicular Technology Conference, 2003. VTC 2003-Fall. 2003 IEEE 58th, 2003.
    [18] W. R. Stevens, TCP/IP Illustrated, Volumn 1: The Protocols, Addison Wesley, 1994.
    [19] A. S. Tanenbaum, Computer Networks, Fourth Edition, Prentice Hall, 2003.

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