本論文針對IEEE802.11的媒體存取控制層(MEDIUM ACCESS CONTROL，MAC)中的DCF(Distributed Coordination Function)比較最近新穎的方法快速碰撞解決機制(FAST COLLISION RESULOTION)做分析，然後改進EDCF(ENHANCE Distributed Coordination Function)協定，將一個區段分成三個區間，每個優先權(Priority)有各自要更新和對照的參數，根據網路負載程度給於動態調整，如我們在之後要提到UR(Utilization Ratio)，P(Avearge collision probability)，都是扮演重要的角色，同時，由於各個優先權全都在屬於自己的區間競爭通道，我們也動態的調整CWmax、CWmin得範圍，最後，藉由模擬的結果，得到高傳輸率(throughput)和低延遲時間(delay)的效果，符合多媒體傳輸的條件，提供較好的服務品質保證(QoS)。

　　In recent years,mobile ad hoc network has become a widely used technology which is based on IEEE 802.11 standards.First,we study FCR(FAST COLLISION RESULOTION and compare with DCF(Distributed Coordination Function).

　　Recently,more and more attention has been attracted to providing quality of service (QoS) for real-time traffic in wireless ad hoc networks as the increase of real-time applications. However, the Distributed Coordination Function (DCF), the popular communication protocol in IEEE 802.11 standard, fails to provide QoS guarantee for real-time applications.

　　In this thesis, we proposed a dynamic adaptive area based on Utilization Ratio control to improve the throughput and delay and then to transmit multimedia in wireless local area network.

[1] Romdhani, L.; Qiang Ni; Turletti, T., ＂Adaptive EDCF: Enhanced Service Differentiation for IEEE 802.11 Wireless Ad-hoc Networks＂,IEEE Wireless Communications and Networking, Conference , Volume: 2 , pp. 16-20 March 2003
[2] IEEE WG, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer(PHY) Specifications＂, IEEE 802.11 Standard, 1999.
[3] IEEE WG, “802.11e Draft 6.0＂, May 2003 [4] S. Mangold, S. Choi, P. May, O. Klein, G. Hiertz and L. Stibor, "IEEE 802.11e Wireless LAN for Quality of Service", in Proceedings of European Wireless, Volume: 1, pp. 32-39, Florence, Italy, February 2002.
[4] Y. Kwon, Y. Fang, and H. Latchman, “A novel medium access control
protocol with fast collision resolution for wireless LANs,” in Proc. IEEE
Int. Conf. Computer Communications (INFOCOM’03), San Francisco,
CA, Mar./Apr. 2003.
[5] M. Veeraraghavan, N. Cocker, and T. Moors, “Support of voice services
in IEEE 802.11 wireless LANs,” in Proc. IEEE INFOCOM, vol. 1, 2001,
pp. 488–497.
[6] V. Kanodia, C. Li, A. Sabharwal, B. Sadeghi, and E. Knightly, “Distributed Priority Scheduling and Medium Access in Ad Hoc Networks” ACM Wireless Networks vol.8, pp 455–466, 2002
[7] The Institute of Electrical and Electronics Engineers, Inc. IEEE Std 802.11 – WirelessLAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, 1999
edition. 42
[8] A. and C. Castelluccia, “Differentiation Mechanisms forIEEE 802.11,” Proc. IEEE Infocom 2001, Apr. 2001.
[9] J. Deng and R. S. Chang, “A Priority Scheme for IEEE 802.11 DCF Access Method,” IEICE Trans. Commun.,vol. 82-B, no. 1, Jan. 1999.
[10] IEEE 802.11e draft/D5.0, “Part 11:Wireless MediumAccess Control (MAC) and Physical Layer (PHY) Specifications:Medium Access Control (MAC) Enhancements for Quality of Service (QoS),” Nov. 2003.