基于動態(tài)幀聚合機制的WLAN傳輸優(yōu)化
發(fā)布時間:2018-03-19 19:13
本文選題:無線網絡 切入點:傳輸優(yōu)化 出處:《國防科學技術大學》2014年碩士論文 論文類型:學位論文
【摘要】:隨著無線網絡的廣泛應用,網絡效率和性能成為關注的重點。802.11n提出幀聚合技術,可以有效的提高無線網絡的傳輸帶寬。論文針對動態(tài)幀聚合進行研究,具有重要的理論和應用價值。論文首先介紹了MAC層幀聚合研究現狀,分析了固定幀長幀聚合的性能。然后針對一定規(guī)模的無線網絡系統(tǒng),可以估計系統(tǒng)最大吞吐量情況下的最佳幀長。提出基于誤比特率的的自適應幀聚合機制(Adaptive Frame Aggregative Based on BER,AFABB),根據信道誤比特率動態(tài)調整聚合幀長,以獲得最佳的傳輸帶寬。最后,對NS2仿真軟件的802.11 MAC進行擴展和改進,對提出的算法進行仿真驗證。具體工作如下:(1)利用Markov鏈模型,基于固定幀長,分別對A-MSDU、A-MPDU和兩級幀聚合進行理論分析。綜合衡量網絡利用率和時延,A-MPDU可以獲得較好的信道利用率和傳輸時延。由于信道誤比特率是動態(tài)變化的,當采取固定幀長,MAC層利用率不能夠得到最佳。(2)根據理論模型,估計一定信道誤比特率條件下,使得信道利用率最大的最佳數據單元長度。以此為基礎,提出自適應幀聚合的算法,根據信道誤比特率,自適應選擇最佳的幀長進行聚合,提升MAC層利用率。(3)原有NS2仿真軟件的802.11MAC層每次只獲取一份數據包,不能支持幀聚合。論文在NS2仿真軟件的基礎上,對802.11MAC采取增加緩存的方法,改變獲取數據包數量,進行幀聚合支持。構建仿真場景,對AFABB算法進行仿真驗證。結果表明,與固定幀長策略相比,AFABB算法對于不同的誤碼率條件能夠獲得更高的MAC層利用率。
[Abstract]:With the wide application of wireless networks, network efficiency and performance become the focus of attention. 802.11n proposed frame aggregation technology, which can effectively improve the transmission bandwidth of wireless networks. This paper first introduces the research status of MAC layer frame aggregation, and analyzes the performance of fixed frame length frame aggregation. The optimal frame length can be estimated in the case of maximum throughput of the system. Adaptive Frame Aggregative Based on error rate based frame aggregation mechanism is proposed to dynamically adjust the aggregated frame length according to the channel bit error rate in order to obtain the best transmission bandwidth. Finally, an adaptive frame aggregation mechanism based on bit error rate (BER) is proposed. The 802.11 MAC of NS2 simulation software is extended and improved, and the proposed algorithm is simulated and verified. The detailed work is as follows: using Markov chain model, based on fixed frame length, The theoretical analysis of A-MSDUU A-MPDU and two-stage frame aggregation is carried out respectively. A better channel utilization and transmission delay can be obtained by synthetically measuring network utilization and delay. When using fixed frame length MAC layer utilization can not get the best. 2) based on the theoretical model, the optimal length of data unit which makes the maximum channel utilization rate can be estimated under the condition of certain channel bit error rate. An adaptive frame aggregation algorithm is proposed, which adaptively selects the best frame length to aggregate according to the channel bit error rate (BER), and improves the utilization ratio of the MAC layer. (3) the 802.11 MAC layer of the original NS2 simulation software only acquires one packet at a time. On the basis of NS2 simulation software, this paper adopts the method of increasing buffer for 802.11 MAC, changes the number of packets and supports frame aggregation. The simulation scene is constructed and the AFABB algorithm is simulated and verified. Compared with the fixed frame length strategy, the proposed algorithm can achieve higher MAC layer utilization under different BER conditions.
【學位授予單位】:國防科學技術大學
【學位級別】:碩士
【學位授予年份】:2014
【分類號】:TN925.93
【共引文獻】
相關期刊論文 前1條
1 姜紹君;王穎;;CSMA/CA算法的退避失敗概率的分析[J];計算機應用與軟件;2015年10期
相關碩士學位論文 前4條
1 樊鷺;無線Mesh網擁塞控制機制研究[D];海南大學;2012年
2 于菡蕾;空間環(huán)境中傳輸控制層協(xié)議研究[D];沈陽理工大學;2014年
3 杜千;流媒體系統(tǒng)中變動分段緩存策略的研究[D];北京交通大學;2015年
4 周美玲;代理移動IPv6切換技術優(yōu)化的研究及仿真[D];華南理工大學;2015年
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