Ad hoc wireless networks是一種不需要任何基礎建設架構支援的無線網路，是一種相當方便的區域網路，這種特殊的網路型態，適合用於像是戰地、災難緊急救助等等臨時性需求而架設的網路，以便於在無任何基礎建設架構支援的環境下還能彼此送收資料，互相通訊。
在一區域內的使用者個數不一定是固定的，所以，網路的負載可能會隨時間而改變。本篇論文提出一個Priority MAC Scheme的機制，工作站一開始不像802.11 MAC一樣使用CWmin來當作初始值，而使用一個較大的CW來當作初始值。藉此，能在更短的時間內降低collision發生的機會。而能讓網路更為穩定。即使在網路為高負載下，仍然能較快速降低collision rate。

The emerging widespread use of real-time multimedia applications over wireless networks makes the support of Quality of Service (QoS) a key problem. In this paper, we focus on QoS support mechanisms for IEEE 802.11 Wireless ad-hoc networks.
First, we review the IEEE 802.11 standard and other enhanced MAC schemes that have been proposed to support QoS for 802.11 ad hoc networks. Then we propose a new priority MAC scheme which uses the different initial contention window instead of CWmin in IEEE 802.11 MAC to reduce the collision rate, then reduces the average delay and increases the throughput.

第一章 導論
1.1 簡介
第二章 研究背景與相關研究
2.1 研究背景
2.1.1 IEEE 802.11簡介
2.1.2 分散式協調功能(Distributed Coordination Function, DCF)
2.1.3 IEEE 802.11 DCF運作機制
2.1.4 Hidden terminal problem與exposed terminal problem
2.2 相關研究
2.2.1 Priority-based schemes
2.2.2 Fair Scheduling-based
2.3 Other related works
2.3.1 EDCF
2.3.2 Adaptive EDCF
第三章 Adaptive initial contention window scheme
3.1提出的基本構想
3.2 Adaptive initial contention window scheme
3.2.1 Setting CW after each successful transmission
3.2.2 Setting CW after each collision
3.2.3 Iinitial CW
第四章 電腦模擬與模擬分析
4.1 模擬環境設定
4.2 模擬結果與分析
4.2.1 mean delay
4.2.2 collision rate
4.2.3 throughput
4.2.4 模擬node離開的情形
第五章 結論
參考文獻(Reference

參考文獻 (Reference)
[1] Aad, I.; Castelluccia, C, “Differentiation mechanisms for IEEE 802.11” INFOCOM 2001. Twentieth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE Volume 1, 22-26 April 2001 Page(s):209 - 218 vol.1
[2] C.T. Chou, K.G. Shin and S. ShanKar N., “Inter Frame Space (IFS) Based Service Differentiation in IEEE 802.11 Wireless LANS”, IEEE VTC’03-Fall, Orlando, Florida, USA, 2003
[3] D.J. Deng and R.S. Chang, “A priority scheme for IEEE 802.11 DCF access method”, IEICE Trans. commun., vol. E82-B, num. 1, pp. 96-102, January 1999
[4] IEEE 802.11 WG, Draft Supplement to STANDARD for Telecommunications and Information Exchange Between Systems – LAN/WAN Specific Requirements – Part 11: Wireless Medium Access Control (MAC) and physical layer (PHY) specifications : Medium Access Control (MAC) Enhancements for Quality of Service (QoS), IEEE 802.11e/D2.0, NOV 2001
[5] I. Aad and C. Castellucia, “Priorities in WLANs”, Computer networks, vol. 41/4, pp. 505-526, February 2003
[6] JANG-PING SHEU, CHI-HSUN LIU, SHIH-LIN WU, and YU-CHEE TSENG, “A priority MAC Protocol to support Real-Time Traffic in Ad Hoc Networks” 2003 Kluwer Academic Publishers.
[7] J.L. Sobrinho and A.S. Krishnakumar. “Real-time traffic over the IEEE 802.11 MAC”, Bell Labs Technical Journal, vol. 1, num. 2, pp. 172-187, Autumn 1996
[8] J.L. Sobrinho and A.S. Krishnakumar, “Quality of service in ad hoc carrier sense multiple access wireless networks”, IEEE Journal on Selected Area in Communications, pp. 1353-1368, August 1999
[9] J, Zhao, Q. Zhang, W. Zhu and Y.Q. Zhang, “Throughput and QoS Optimization in IEEE 802.11 WLAN”, 3Gwireless2002 + WAS2002, San Francisco, USA, May 2002
[10] K. Kim, S. Shin and K. Kim, “A novel MAC scheme for prioritized services in IEEE 802.11a wireless LAN”, Proc. ATM (ICATM 2001) and High Speed Intelligent Internet Symposium Joint 4th IEEE International Conference, pp. 196-199, April 2001
[11] Kwon, Y.; Fang, Y.; Latchman, H.; “A novel MAC protocol with fast collision resolution for wireless LANs” INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies. IEEE
Volume 2, 30 March-3 April 2003 Page(s):853 - 862 vol.2
[12] L. Romdhani, Q. Ni and T. Turletti, “Adaptive EDCF: Enhanced Service Differentiation for IEEE 802.11 Wireless Ad-Hoc Networks”, IEEE WCNC, New Orleans, Louisiana, USA, March 2003
[13] Malli, M.; Qiang Ni; Turletti, T.; Barakat, C.; “Adaptive fair channel allocation for QoS enhancement in IEEE 802.11 wireless LANs” Communications, 2004 IEEE International Conference on Volume 6, 20-24 June 2004 Page(s):3470 - 3475 Vol.6
[14] M.Adamou, S. Khanna, I. Lee, I. Shin and S. Zhou, “Fair Real-time Traffic Scheduling over a Wireless LAN”, 22nd IEEE Real-Time Systems Symposium, RTSS 2001, London, UK, December, 2001
[15] Mico, F.; Cuenca, P.; Orozco-Barbosa, L., “QoS in IEEE 802.11 wireless LAN: current research activities” Electrical and Computer Engineering, 2004. Canadian Conference on Volume 1, 2-5 May 2004 Page(s):447 - 452 Vol.1
[16] Nakano, K;Olariu, S, “Randomized initialization protocols for ad hoc networks” Parallel and Distributed Systems, IEEE Transactions on Volume 11, Issue 7, July 2000 Page(s):749 - 759
[17] Nah-Oak Song; Byung-Jae Kwak; Jabin Song; Miller, M.E.; Enhancement of IEEE 802.11 distributed coordination function with exponential increase exponential decrease backoff algorithmVehicular Technology Conference, 2003. VTC 2003-Spring. The 57th IEEE Semiannual Volume 4,22-25 April 2003 Page(s):2775 - 2778 vol.4
[18] N.H. Vaidya, P. Bahl and S. Gupta, “Distributed Fair Scheduling in a Wireless LAN”, Proceedings of ACM 6th International Conference on Mobile Computing and Networking (MobiCom 2000), pp. 167-178, 2000
[19] S.T. Sheu and T.F. Sheu, “A Bandwidth Allocation/Sharing/ Extension Protocol for Multimedia over IEEE 802.11 Ad Hoc Wireless LANs”, IEEE Journal on Selected Areas in Communications, vol. 19, num. 10, pp. 2065-2081, October 2001
[20] W.T. Chen, B.B. Jian, and S.C. Lo, “An Adaptive Retransmission Scheme with QoS Support for the IEEE 802.11 MAC Enhancement”, Vehicular Technology Conference 2002 (VTC Spring 2002), Birmingham, Alabama, USA, May 2002
[21] W.T. Chen, Y.M. Lin and S.C. Lo, “Priority-Based Contention Control in IEEE 802.11 Wireless LANs”, 16th International Workshop on Communications Quality & Reliability (CQR 2002), Okinawa, Japan, May 2002
[22] Y.J. Kim, H.D. Park, “A priority scheme for IEEE 802.11 with guaranteeing QoS”, The 2002 International Technical Conference On Circuits/Systems, Computer and communications, ITC-CSCC-2002, Phuket, Thailand, July 2002