TCP在每次能夠發送得最大封包量取決於擁塞視窗(Congestion Window, cwnd)的大小，當cwnd成長時，此時存在Ad-Hoc網路上傳送路徑中的封包量亦隨之增加，造成過多的封包因無法競爭到傳輸媒介的使用權而在等待下一次的傳送機會，再來繼續競爭。因此當網路中的擁塞狀況或節點間的干擾狀況並未獲得改善，封包的傳送延遲將會快速的增加。本論文提出一個針對多重跳躍Ad-Hoc具有跨層級TCP擁塞視窗控制機制，依據封包在中間節點的傳送過程中，在MAC(Media Access Control) Layer的競爭狀況來動態的調整TCP的擁塞視窗。將TCP的擁塞控制視窗維持在適當的值來減少封包的傳送延遲以提升單位時間的封包接收量。為了驗證我們所提出在多重跳躍Ad-Hoc網路上的跨層級TCP擁塞視窗控制機制，我們使用NS-2來模擬並且與其他的TCP機制CWL以及TCP NewReno比較，證明我們的機制在具負載的網路情況下能有更好的表現。

The amount of packets on-the-fly in a wireless ad-hoc network increases when the size of congestion window and the number of hop count increase. It is possible that packets may have to retransmit because large amount of on-the-fly packets may increase the media contention. Besides, packet delay can grow rapidly when the wireless network becomes congested or the channel interference remains unresolved. This thesis presents a cross-layer TCP congestion window control mechanism for multihop ad-hoc networks to dynamically adjust the size of congestion window according to the MAC-layer contention statistics measured at each hop along the routing path. With the proposed scheme, the congestion window of each traffic flow can be dynamically set to an appropriate size to reduce packet delay and increase flow throughput. For the purpose of evaluation, we perform simulations on NS-2. The simulation results have shown the advantage of our proposed scheme over the two previous works, NewReno and CWL(Congestion Window Limit), especially when the ad-hoc network is loaded with background traffic.

第一章 導論
1.1 研究動機
1.2 研究方法
1.3 章節介紹
第二章 TCP在無線Ad-Hoc網路上的相關研究
2.1 無線隨意式(Ad-Hoc)網路
2.2 在無線網路上TCP的效能改進
2.2.1 Infrastructure模式下TCP的效能改進
2.2.2 Ad-Hoc模式下TCP的效能改進
2.2.2.1 限制TCP的擁塞控制視窗
2.2.2.2 基於MAC Layer為考量來改良TCP的效能
2.2.2.3 依據Network Layer的狀況改善TCP效能
2.2.2.4 修改Transport Layer來改進TCP效能
2.3 Ad-Hoc網路上改良TCP效能機制的比較
2.4 本論文的跨層級TCP擁塞視窗控制
第三章 跨層級的TCP擁塞視窗控制
3.1 網路狀況的評估與擁塞視窗的調整
3.1.1 計算網路中的封包數量
3.1.2 依據RTS重傳次數來判定網路狀況
3.1.3 TCP擁塞視窗的控制
3.2 整體運作流程
第四章 模擬機制與結果分析
4.1 NS模組架構
4.2 環境設定與網路拓樸
4.3 模擬結果與分析討論
4.3.1 擁塞視窗的變化圖
4.3.2 在不同節點移動速度下的影響
4.3.3 比較其它因素的影響
4.3.4 不同路由協定下的測試
第五章 結論與未來工作
5.1 結論
5.2 未來的工作
REFERENCES
Index
附 錄

[1] IEEE 802.11, 1999 ed. (ISO/IEC 8802-11: 1999), “IEEE Standards for Information Technology — Telecommunications and Information Exchange between Systems — Local and Metropolitan Area Network — Specific Requirements — Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.”
[2] Marina del Rey, “Transmission Control Protocol,” RFC-793, Sep. 1981.
[3] K. Ramakrishnan, “The Addition of Explicit Congestion Notification to IP,” RFC-3168, Sep. 2001.
[4] C. Perkins, “Ad hoc On-Demand Distance Vector (AODV) Routing,” RFC-3561, July 2003.
[5] C.P. Fu and S.C. Liew, “TCP Veno: TCP Enhancement for Transmission Over Wireless Access Networks,” IEEE Journal on Selected Areas in Communications, Volume 21, Issue 2, pp. 216 – 228, Feb. 2003.
[6] G. Buchholcz, T. Ziegler, and T. Van Do, “TCP-ELN: On the Protocol Aspects and Performance of Explicit Loss Notification for TCP over Wireless Networks,” First International Conference on Wireless Internet, pp. 172 – 179, 10-14 July 2005.
[7] C. Kai, X. Yuan, and K. Nahrstedt, “On setting TCP's congestion window limit in mobile ad hoc networks,” IEEE International Conference on Communications, Volume 2, pp. 1080 - 1084, 11-15 May 2003.
[8] M. Gunes and D. Vlahovic, “The performance of the TCP/RCWE enhancement for ad-hoc networks,” Seventh International Symposium on Computers and Communications, pp. 43 - 48,1-4 July 2002.
[9] G. Boggia, P. Camarda, L.A. Grieco, T. Mastrocristino, and G. Tesoriere, “A Cross-layer Approach to Enhance TCP Fairness in Wireless Ad-hoc Networks,” 2nd International Symposium on Wireless Communication Systems, pp. 498 – 502, 5-7 Sept. 2005.
[10] K.W. Kim, P. Lorenz, and M.M.O. Lee, “A new tuning maximum congestion window for improving TCP performance in MANET,” Proceedings of the Systems Communications, pp. 73 – 78, 14-17 Aug. 2005.
[11] S. Papanastasiou, L. M. MacKenzie, and Mohamed Ould-Khaoua, “Reducing the degrading effect of hidden terminal interference in MANETs,” Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems, October 2004.
[12] Z. Fu, P. Zerfos, H. Luo, S. Lu, L. Zhang, and M. Gerla, “The impact of multihop wireless channel on TCP throughput and loss,” IEEE INFOCOM 2003, Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies, Volume 3, pp. 1744 – 1753, 30 March - 3 April 2003.
[13] Z. Fu, H. Luo, P. Zerfos, S. Lu, L. Zhang, and M. Gerla, “The impact of multihop wireless channel on TCP performance,” IEEE Transactions on Mobile Computing, Volume 4, Issue 2, pp. 209 - 221 March-April 2005.
[14] M. Gunes, M. Hecker, and I. Bouazizi, “Influence of adaptive RTS/CTS retransmissions on TCP in wireless and ad-hoc networks,” Eighth IEEE International Symposium on Computers and Communication, Volume 2, pp. 855 – 860, 2003.
[15] K. Xu, M. Gerla, L. Qi, and Y. Shu, “Enhancing TCP Fairness in Ad Hoc Wireless Networks using Neighborhood Red,” Proc. ACM MOBICOM, San Diego, CA, USA, pp. 16 – 28, Sep. 2003.
[16] K. Chandran, S. Raghunathan, S. Venkatesan, and R. Prakash, “A feedback-based scheme for improving TCP performance in ad hoc wireless networks,” IEEE [see also IEEE Wireless Communications] Personal Communications, Volume 8, Issue 1,pp. 34 – 39, Feb. 2001.
[17] G. Holland and N. Vaidya, “Analysis of TCP Performance over Mobile Ad Hoc Networks,” ACM Wireless Networks, Volume 8, no. 2, pp. 275–88, Mar. 2002.
[18] J. Liu and S. Singh, “ATCP: TCP for Mobile Ad Hoc Networks,” IEEE Journal on Selected Areas in Communications, Volume 19, Issue 7, pp. 1300 – 1315, July 2001.
[19] D. Kim, C. Toh, and Y. Choi, “TCP-BuS: improving TCP performance in wireless ad hoc networks,” IEEE International Conference on Communications, Volume 3, pp. 1707 – 1713, 18-22 June 2000.
[20] J.X. Zhou, B.X. Shi, and L. Zou; “Improve TCP performance in ad hoc network by TCP-RC,” 14th IEEE on Personal, Indoor and Mobile Radio Communications, Volume 1, pp. 216 - 220, 7-10 Sept. 2003.
[21] T. Goff, N.B. Abu-Ghazaleh, and D.S. Phatak, “Analysis of TCP performance on ad hoc networks using preemptive maintenance routing,” International Conference on Parallel Processing, pp. 232 - 239, 3-7 Sept. 2001.
[22] A.K. Singh and K. Kankipati, “TCP-ADA: TCP with adaptive delayed acknowledgement for mobile ad hoc networks,” IEEE Wireless Communications and Networking Conference, Volume 3, pp. 1685 – 1690, 21-25 March 2004.
[23] W. Lilakiatsakun and A. Seneviratne, “TCP performances over wireless link deploying delayed ACK,” The 57th IEEE Semiannual Vehicular Technology Conference, Volume 3, pp. 1715 - 1719, 22-25 April 2003.
[24] D. Kim, C.K. Toh, and H.J. Jeong, “An Early Retransmission Technique to Improve TCP Performance for Mobile Ad Hoc Networks,” 15th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Volume 4, pp. 2695 - 2699, 5-8 Sept. 2004.
[25] The VINT Project. The UCB/LBNL/VINT Network Simulator—ns (version 2) Web site: http://mash.cs.berkeley.edu/ns.
[26] Kostas Pentikousis, “Poisson traffic generator patch for NS-2.27,” Web site: http://www.cs.stonybrook.edu/~kostas/src/poisson/install-poisson-ns-2.27.html.
[27] “IEEE 802.11 WLAN standard,” Web site: http://standards.ieee.org/getieee802.