整合AIFS及CW對於IEEE 802.11e效能之分析

Performance Assessment for Integration of AIFS and CW in IEEE 802.11e under Saturation Condition

張欣豪(Hsin-Hao Chang)

指導教授 ： 黃依賢

元智大學/資訊學院/資訊工程學系/碩士(2006年)

https://doi.org/10.6838/YZU.2006.00294

摘要

近年來隨著無線通訊的迅速發展，使得無線區域網路應用層面越來越廣。而在市面上的WLAN產品大都標榜傳輸效能可以到達高標準的流通率 (Throughput)，但使用者往往經過實際應用後，才會發現真正的效能其實遠低於產品所給予的期望值。最近，一些研究主要探討Contention Window (CW)對於IEEE 802.11e EDCA機制下的探討，但是忽略了Arbitration Inter-Frame Space (AIFS)的影響。本文主要是完成IEEE 802.11e EDCA機制下的分析。我們以馬可夫串列之方法，提出三維的馬可夫模型，並著重於不同AC間的 AIFS 以及CW以不同的資料量來分析其效能。這個模型，可以使我們更深入的探討，使用不同的參數分析，來了解其對效能的影響。藉由所提出之模型，希望能達到更準確的流通率 (Throughput) 分析。

關鍵字: 無線網路, Enhanced distributed channel access (EDCA), 馬可夫模型, 效能分析, 飽和狀態.

關鍵字

無線網路 ； Enhanced distributed channel access (EDCA) ； 馬可夫模型 ； 效能分析 ； 飽和狀態

並列摘要

Abstract
The new standard IEEE 802.11e is specified to support quality-of-service in wireless local area networks (WLAN). Recent research related to the EDCA performance is only simulation results or analyzed focused on the contention window (CW), but the effect of arbitration inter-frame spaces (AIFS) is ignored. This paper aims at providing an analytical model that captures the operation of the AIFSs, contention window sizes and retry limits differentiation for the EDCA mechanism under saturation condition based on a three-dimensional Markov Chain model. The system performance is analyzed and compared in terms of system throughput for differentiation services traffic of the EDCA under saturation condition. The analytical model provides an in-depth understanding and insights into the EDCA protocol, and effectiveness of different parameters on the system performance is investigated through extensive numerical and simulation results.

並列關鍵字

WLAN ； Enhanced distributed channel access (EDCA) ； Three-dimension Markov Chain ； Performance analysis ； Saturation conditions

參考文獻

[2] A. Imad and C. Claude, “Differentiation mechanisms for IEEE 802.11,” in Proc. of IEEE INFOCOM 2001, Anchorage, USA, Apr. 2001, pp. 209-218.

[3] A. Lindgren, A. Almquist and O. Schel´en, “Evaluation of Quality of Service schemes for IEEE 802.11 wireless LANs,” in Proc. of the 26th Annual IEEE Conference on Local Computer Networks, Lulea, Sweden, Nov. 2001, pp. 348-351.

[5] S. Choi, J. D. Prado, S. Shankar and S. Mangold, “IEEE 802.11e Contention-Based Channel Access (EDCF) Performance Evaluation,” in Proc. of ICC 2003, Alaska, USA, May 2003, pp. 1151-1156.

[6] A. Grilo and M. Nunes, “Performance Evaluation of IEEE 802.11e,” in Proc. of PIMRC’02, Lisboa, Portugal, Sept. 2002, pp. 511-517.

[7] D. Qiao and K. G. Shin, “Achieving Efficient Channel Utilization and Weighted Fairness for Data Communications in IEEE 802.11 WLAN under the DCF,” in Proc. of IWQoS’2002, Miami Beach, USA, May 2002, pp. 227-236.