具有波以松封包抵達程序之IEEE 802.11無線區域網路之效能評估

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研究生：	陳維歆 wei-sin Chen
論文名稱：	具有波以松封包抵達程序之IEEE 802.11無線區域網路之效能評估 Performance Evaluation of IEEE 802.11 Wireless Local Area Networks with Poisson Packet Arrivals
指導教授：	鍾順平 Shun Ping Chung
口試委員:	林永松 Yeong-Sung Lin 王乃堅 Nai-Jian Wang
學位類別：	碩士 Master
系所名稱：	電資學院 - 電機工程系 Department of Electrical Engineering
論文出版年：	2005
畢業學年度：	93
語文別：	英文
論文頁數：	109
中文關鍵詞：	無線區域網路、效能評估、波以松
外文關鍵詞：	IEEE 802.11, Poisson, Performance Evaluation
相關次數：	點閱：264 下載：1
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在這篇論文中，我們提出二種使用離散馬可夫鏈的解析數學模型去計算IEEE 802.11無線網路的成功送達率以及每個訊框的平均延遲。在這邊我們不是假設在每一個行動台中總是有封包要傳送，取而代之的，我們考慮較真實的情形，也就是Poisson的流量模型。雖然在此我們只研究RTS/CTS進接機制，但是我們的分析可以輕易延伸到basic進接機制。此外，每一個行動台有一個有限的佇列，並且被塑模成為M/M/1排隊系統以計算穩態機率分佈。為了要提供服務差異性，我們在DCF上面使用優先權方法。DCF的三個參數是根據使用者的優先權來設定：初始視窗大小，視窗擴增係數以及DIFS。因為在無線通道會遭受遠比有線通道更高的位元錯誤率，所以我們也考慮了有著非零位元錯誤率的情境。因此，我們考慮了三個情境：理想通道且不具有優先權，理想通道且含有優先權，衰減通動且不具有優先權。系統人數，提供負載跟位元錯誤率對於我們有興趣的每一種使用者的系統效能量度的影響是透過所提出的兩種數學模型去計算。最後但並非最不重要的，我們使用C語言作電腦模擬來驗證這兩種數學方式結果的正確性。我們可以看到，整體而言，第一種數學模型的結果可以達到比第二種數學模型的結果更好的準確性。

We propose two analytical models using discrete-time Markov chain to compute the throughput and delay for IEEE 802.11 WLAN. Instead of assuming that there is always a frame at each station ready to send, we consider the more realistic Poisson arrival traffic model. Although we study only the RTS/CTS access mechanism, the analysis can be easily extended to the basic access mechanism. Furthermore, each station has a finite queue and is modeled as an M/M/1 queueing system to compute the steady-state probability distribution. In order to support service differentiation, we employ priority schemes in DCF. Three parameters in DCF are set according to the user’s priority: initial window size, window increasing factor and DIFS. Since the wireless channel suffers from much higher bit error rate (BER) than its wireline counterpart, we also consider the scenarios with nonzero BER. Therefore, we consider three scenarios: ideal channel without prioritization, ideal channel with prioritization, and fading channel without prioritization. The effects of number of users, offered load, and BER on the performance measures of interest for each class of users are shown via both analytical methods. Last but not least, computer simulation program written in C language is run to verify the accuracy of the analytical results. It is shown that overall speaking, the first analytical model can achieve better accuracy than the second analytical model.

List of Figures
List of Tables
Chapter 1		Introduction
Chapter 2		System Model
	2.1	Review of IEEE 802.11
	     2.1.1	Architecture
	     2.1.2	Physical Layer
	     2.1.3	MAC Sublayer
	     2.1.4	Distributed Coordination Function (DCF)
	2.2	Mathematical Model
	     2.2.1	The Ideal Channel without Prioritization
	     2.2.2	Performance Evaluation
	     2.2.3	The Ideal Channel with Prioritization
	     2.2.4	The Fading Channel without Prioritization
Chapter 3		Numerical Results
	3.1	The Ideal Channel Condition without Prioritization
	3.2	The Ideal Channel Condition with Prioritization
	     3.2.1	Window Increasing Factor
	     3.2.2	Initial Window Size
              3.2.3	Combination of Window Increasing Factor and Initial Window Size
              3.2.4	DIFS
	3.3	The Fading Channel without Prioritization
Chapter 4		Conclusion
References

                                

[1] G. Bianchi, “Performance Analysis of the IEEE 802.11 Distributed Coordination Function,” IEEE JSAC, Vol. 18, pp. 535-547, Mar. 2000.
[2] F. Eshghi and A. K. Elhakeem, “Performance Analysis of Ad Hoc Wireless LANs for Real-Time Traffic,” IEEE JSAC, Vol. 21, No. 2, pp. 204-215, Feb. 2003.
[3] Z. Hadzi-Velkov and B. Spasenovski, “Saturation Throughput – Delay Analysis of IEEE 802.11 DCF in Fading Channel,” IEEE ICC '03, pp. 121-126, 2003.
[4] Y. Xiao, “Backoff-based Priority Schemes for IEEE 802.11,” IEEE ICC '03, pp. 1568-1572, 2003.
[5] E. Ziouva and T. Antonakopoulos, “CSMA/CA Performance under High Traffic Conditions: Throughput and Delay Analysis,” ELSEVIER Computer Communication 25, pp. 313-321, 2002.
[6] J. Zhao, Z. Guo, Q. Zhang and W. Zhu, “Performance Study of MAC for Service Differentiation in IEEE 802.11,” IEEE GLOBECOM '02, pp. 778-782, 2002.
[7] J. Hui and M. Devetsikiotis, “Designing Improved MAC Packet Schedulers for 802.11e WLAN,” IEEE GLOBECOM '03, pp. 184-189, 2003.
[8] A. Chen, Li-Chun Wang, D. S. L. Wei and K. Naik, “NICE – A Decentralized Medium Access Control Using Neighborhood Information Classification and Estimation for Multimedia Applications in Ad Hoc 802.11 Wireless,” IEEE ICC '03, pp. 208-212, 2003.
[9] G. Bianchi, “IEEE 802.11 – Saturation Throughput Analysis,” IEEE Commun. Lett., Vol. 2, pp. 318-320, Dec. 1998.
[10] Y. Xiao and J. Rosdahl, “Throughput and Delay Limits of IEEE 802.11,” IEEE Commun. Lett., Vol.6, pp. 355-357, Aug. 2002.
[11] I. Aad and C. Castelluccia, “Differentiation Mechanisms for IEEE 802.11”, INFOCOM 2001, pp. 209-218, 2001.
[12] IEEE 802.11 WG, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification, Aug. 1999.
[13] B. P. Crow, I. Widjaja, J. G. Kim, and P. T. Sakai, “IEEE 802.11 Wireless Local Area Networks,” IEEE Commun. Mag, Vol. 35, pp. 116-126, Sep. 1997.
[14] J. W. Robinson and T. S. Randhawa, “Saturation Throughput Analysis of IEEE 802.11e Enhanced Distributed Coordination Function” IEEE JSAC, Vol. 22, pp. 917-928, June 2004.
[15] D. Gross and C. M. Harris, Fundamentals of Queueinf Theorem, 3rd Edition, John Wiley.

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