本文選題：MAC　切入點(diǎn)：WiFi　出處：《天津大學(xué)》2014年碩士論文

【摘要】：隨著WiFi與ZigBee技術(shù)的不斷發(fā)展以及他們?cè)谌粘Ｉ钪邪l(fā)揮著越來越重要的作用,如高速網(wǎng)絡(luò)接入和火災(zāi)監(jiān)控等,這兩種異構(gòu)網(wǎng)絡(luò)得到了越來越廣泛的部署。由于WiFi和ZigBee共享2.4GHz ISM(Industrial Sciencific Medical)頻段且常同時(shí)出現(xiàn)在同一環(huán)境中,當(dāng)網(wǎng)絡(luò)節(jié)點(diǎn)密度較大時(shí)兩者的信道頻譜將發(fā)生重疊,引起共信道干擾。相比CSMA機(jī)制,子載波置零技術(shù)可以通過分離WiFi與ZigBee的信號(hào)頻譜更好地實(shí)現(xiàn)兩者共存,且信號(hào)的并行傳輸使得頻譜資源得到充分利用。本文針對(duì)非連續(xù)子載波正交頻分復(fù)用(Non-Continuous Orthogonal Frequency Division Multiplexing,NC-OFDM)物理層在WiFi與ZigBee共存場(chǎng)景的應(yīng)用,為WiFi設(shè)計(jì)一個(gè)與之相適應(yīng)的媒體接入控制(Medium Access Control,MAC)協(xié)議:ZiMAC。ZiMAC關(guān)鍵技術(shù)主要有三部分,一是根據(jù)WiFi與ZigBee信道特點(diǎn)而重新設(shè)計(jì)的載波偵聽功能,它包括新的信道狀態(tài)定義以及判定物理層應(yīng)該采用的發(fā)送模式;二是根據(jù)應(yīng)用場(chǎng)景需要而改進(jìn)的分布式信道接入機(jī)制;三是為保證ZigBee節(jié)點(diǎn)在Duty-Cycle工作方式下能夠及時(shí)接入信道并進(jìn)行數(shù)據(jù)傳輸而設(shè)置的計(jì)數(shù)器機(jī)制,它也將左右WiFi物理層發(fā)送模式的選擇。本文在GNU Radio/USRP軟件無線電平臺(tái)上實(shí)現(xiàn)了ZiMAC協(xié)議,并驗(yàn)證其各部分功能的正確性,同時(shí)對(duì)ZiMAC的性能進(jìn)行測(cè)試并分析影響其性能的因素。實(shí)驗(yàn)結(jié)果表明,ZiMAC在保證ZigBee與NC-OFDM并行傳輸能獲得較好性能的同時(shí),減少了由于子載波置零而導(dǎo)致的WiFi吞吐率下降:當(dāng)ZigBee的數(shù)據(jù)發(fā)送密度較小時(shí),ZiMAC在1/2帶寬以及3/4帶寬下的相對(duì)吞吐率比單純采用子載波置零模式發(fā)送最大可分別提高約50個(gè)和28個(gè)百分點(diǎn)。
[Abstract]:With the development of WiFi and ZigBee technology, they play more and more important role in daily life, such as high-speed network access and fire monitoring. Because WiFi and ZigBee share the 2.4GHz ISM(Industrial Sciencific frequency band and often appear in the same environment simultaneously, the channel spectrum of the two networks will overlap when the network node density is high. Compared with the CSMA mechanism, the sub-carrier zeroing technique can realize the coexistence of WiFi and ZigBee better by separating the signal spectrum of the WiFi and the ZigBee. The parallel transmission of signals makes full use of spectrum resources. This paper aims at the application of non-continuous Orthogonal Frequency Division multiplexing NC-OFDM physical layer in the scene of coexistence of WiFi and ZigBee. There are three key technologies in designing a medium Access Control (MAC) protocol for WiFi: Zim AC.ZiMAC. One is the carrier interception function redesigned according to the characteristics of WiFi and ZigBee channels. It includes the new channel state definition and the transmission mode to be used in the physical layer, and the improved distributed channel access mechanism according to the needs of the application scenario. The third is the counter mechanism set up to ensure that the ZigBee node can access the channel and transmit data in time under the Duty-Cycle operation mode, which will also influence the choice of the transmission mode of the WiFi physical layer. In this paper, the ZiMAC protocol is implemented on the GNU Radio/USRP software radio platform. At the same time, the performance of ZiMAC is tested and the factors affecting its performance are analyzed. Reduced WiFi throughput due to subcarrier zeroing: when ZigBee data transmission density is small, the relative throughput of ZigBee at 1 / 2 bandwidth and 3 / 4 bandwidth is higher than that of single subcarrier zero mode transmission. It was about 50 percent higher and 28 percent higher.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN92

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 安靜怡;基于無線傳感器網(wǎng)絡(luò)的室內(nèi)燃?xì)獗O(jiān)測(cè)系統(tǒng)[D];北京郵電大學(xué);2011年

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本文編號(hào)：1670399