本文選題：無(wú)線網(wǎng)絡(luò)　切入點(diǎn)：傳輸優(yōu)化　出處：《國(guó)防科學(xué)技術(shù)大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：隨著無(wú)線網(wǎng)絡(luò)的廣泛應(yīng)用,網(wǎng)絡(luò)效率和性能成為關(guān)注的重點(diǎn)。802.11n提出幀聚合技術(shù),可以有效的提高無(wú)線網(wǎng)絡(luò)的傳輸帶寬。論文針對(duì)動(dòng)態(tài)幀聚合進(jìn)行研究,具有重要的理論和應(yīng)用價(jià)值。論文首先介紹了MAC層幀聚合研究現(xiàn)狀,分析了固定幀長(zhǎng)幀聚合的性能。然后針對(duì)一定規(guī)模的無(wú)線網(wǎng)絡(luò)系統(tǒng),可以估計(jì)系統(tǒng)最大吞吐量情況下的最佳幀長(zhǎng)。提出基于誤比特率的的自適應(yīng)幀聚合機(jī)制(Adaptive Frame Aggregative Based on BER,AFABB),根據(jù)信道誤比特率動(dòng)態(tài)調(diào)整聚合幀長(zhǎng),以獲得最佳的傳輸帶寬。最后,對(duì)NS2仿真軟件的802.11 MAC進(jìn)行擴(kuò)展和改進(jìn),對(duì)提出的算法進(jìn)行仿真驗(yàn)證。具體工作如下:(1)利用Markov鏈模型,基于固定幀長(zhǎng),分別對(duì)A-MSDU、A-MPDU和兩級(jí)幀聚合進(jìn)行理論分析。綜合衡量網(wǎng)絡(luò)利用率和時(shí)延,A-MPDU可以獲得較好的信道利用率和傳輸時(shí)延。由于信道誤比特率是動(dòng)態(tài)變化的,當(dāng)采取固定幀長(zhǎng),MAC層利用率不能夠得到最佳。(2)根據(jù)理論模型,估計(jì)一定信道誤比特率條件下,使得信道利用率最大的最佳數(shù)據(jù)單元長(zhǎng)度。以此為基礎(chǔ),提出自適應(yīng)幀聚合的算法,根據(jù)信道誤比特率,自適應(yīng)選擇最佳的幀長(zhǎng)進(jìn)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(shù)據(jù)包,不能支持幀聚合。論文在NS2仿真軟件的基礎(chǔ)上,對(duì)802.11MAC采取增加緩存的方法,改變獲取數(shù)據(jù)包數(shù)量,進(jìn)行幀聚合支持。構(gòu)建仿真場(chǎng)景,對(duì)AFABB算法進(jìn)行仿真驗(yàn)證。結(jié)果表明,與固定幀長(zhǎng)策略相比,AFABB算法對(duì)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(xué)位授予單位】：國(guó)防科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN925.93

【共引文獻(xiàn)】

相關(guān)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(jì)算機(jī)應(yīng)用與軟件;2015年10期

相關(guān)碩士學(xué)位論文 前4條

1 樊鷺;無(wú)線Mesh網(wǎng)擁塞控制機(jī)制研究[D];海南大學(xué);2012年

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3 杜千;流媒體系統(tǒng)中變動(dòng)分段緩存策略的研究[D];北京交通大學(xué);2015年

4 周美玲;代理移動(dòng)IPv6切換技術(shù)優(yōu)化的研究及仿真[D];華南理工大學(xué);2015年

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本文編號(hào)：1635622