【摘要】：近年來,隨著無線通信技術(shù)的迅猛發(fā)展,WLAN因其擁有高的數(shù)據(jù)吞吐量、高靈活性、低成本、易于擴(kuò)展等特點,已經(jīng)被廣泛應(yīng)用在人們的工作和日常生活中。同時,相比于傳統(tǒng)的有線網(wǎng)絡(luò),無線局域網(wǎng)的性能和服務(wù)質(zhì)量仍有著很大的差距,因而無線局域網(wǎng)成為近年來研究的熱門課題。媒體訪問控制(MAC)層是無線局域網(wǎng)的重要組成部分,MAC層協(xié)議性能對無線局域網(wǎng)的性能起著至關(guān)重要的作用。為了使無線局域網(wǎng)更好地滿足現(xiàn)代通信網(wǎng)絡(luò)的要求,MAC層接入機(jī)制的研究和優(yōu)化具有相當(dāng)重要的研究意義。因此,本文主要對無線局域網(wǎng)WLAN中MAC層接入機(jī)制進(jìn)行了研究。本文在簡要分析了課題的研究背景及意義、國內(nèi)外研究現(xiàn)狀以及相關(guān)的基本概念的基礎(chǔ)上,詳細(xì)介紹了 MAC層協(xié)議內(nèi)容和工作原理。DCF接入機(jī)制是MAC層協(xié)議中基本的接入控制方式,因此本文針對分布式協(xié)調(diào)控制(DCF)接入機(jī)制進(jìn)行了深入研究,并對DCF算法的改進(jìn)機(jī)制進(jìn)行了研究。主要包含以下幾個方面:首先,通過對DCF接入機(jī)制的工作原理的研究,對DCF機(jī)制進(jìn)行了性能仿真,包括系統(tǒng)的吞吐量、碰撞概率等,仿真結(jié)果表明最小窗口、傳輸速率、站點個數(shù)、數(shù)據(jù)幀長對系統(tǒng)的性能都有一定的影響。其次,研究了一種對DCF機(jī)制中的退避機(jī)制的改進(jìn)方案,對該機(jī)制進(jìn)行了仿真,并將改進(jìn)機(jī)制的性能參數(shù)與傳統(tǒng)機(jī)制的性能參數(shù)進(jìn)行了對比分析,仿真結(jié)果證明該改進(jìn)機(jī)制可以提高系統(tǒng)性能。接著,針對帶碰撞避免的載波偵聽多址接入(CSMA/CA)機(jī)制提出了兩種改進(jìn)方案:吞吐量最優(yōu)空閑信道檢測(CCA)門限設(shè)置的方案和基于RSSI的CCA門限動態(tài)調(diào)整的方案,通過對兩種機(jī)制的性能進(jìn)行仿真分析,驗證了這兩種改進(jìn)方案都可以在一定程度上提高系統(tǒng)的性能。
[Abstract]:In recent years, with the rapid development of wireless communication technology, WLAN has been widely used in people's work and daily life because of its characteristics of high data throughput, high flexibility, low cost and easy to expand. At the same time, compared with the traditional wired networks, the performance and quality of service of WLAN is still a big gap, so WLAN has become a hot research topic in recent years. Media access control (MAC) layer is an important part of WLAN. The performance of MAC layer protocol plays an important role in WLAN performance. In order to better meet the requirements of modern communication networks, the research and optimization of MAC layer access mechanism is of great significance. Therefore, this paper mainly studies the access mechanism of MAC layer in WLAN. Based on a brief analysis of the background and significance of the research, the current research situation at home and abroad and the related basic concepts, The content and working principle of MAC layer protocol are introduced in detail. DCF access mechanism is the basic access control mode in MAC layer protocol. Therefore, the distributed coordinated control (DCF) access mechanism is deeply studied in this paper. The improved mechanism of DCF algorithm is also studied. The main contents are as follows: firstly, through the study of the working principle of DCF access mechanism, the performance simulation of DCF mechanism is carried out, including system throughput, collision probability and so on. The simulation results show that the minimum window, transmission rate, etc. The number of sites and data frame length have a certain impact on the performance of the system. Secondly, an improved scheme of Backoff mechanism in DCF mechanism is studied, and the performance parameters of the improved mechanism are compared with those of the traditional mechanism, and the performance parameters of the improved mechanism are compared with those of the traditional mechanism. Simulation results show that the improved mechanism can improve the system performance. Then, two improved schemes for carrier detection multiple access (CSMA/CA) with collision avoidance are proposed: the optimal throughput free channel detection (CCA) threshold setting scheme and the CCA threshold dynamic adjustment scheme based on RSSI. Through the simulation analysis of the two mechanisms, it is proved that the two improved schemes can improve the performance of the system to a certain extent.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN925.93

【引證文獻(xiàn)】

相關(guān)期刊論文 前1條

1 盧玫欣;蘇勝君;施偉斌;樂燕芬;李瑞祥;;Z-MAC協(xié)議改進(jìn)算法[J];軟件導(dǎo)刊;2017年12期

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本文編號：2362844