本文選題：COOJA　切入點：Contiki　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：無線傳感器網(wǎng)絡(luò)由隨機分布在監(jiān)測區(qū)域的節(jié)點組成,可應(yīng)用于環(huán)境監(jiān)測、軍事、工業(yè)控制等領(lǐng)域。網(wǎng)絡(luò)中節(jié)點規(guī)模和復(fù)雜度隨著無線傳感網(wǎng)監(jiān)測應(yīng)用需求而增大,對大規(guī)模無線傳感網(wǎng)絡(luò)仿真工具的要求越來越高。復(fù)雜的無線信道使得節(jié)點間的通信鏈路存在隨機性和不穩(wěn)定性,直接對網(wǎng)絡(luò)仿真評估造成影響。以往無線傳感網(wǎng)研究中,側(cè)重于協(xié)議和能耗,對信道設(shè)計大都基于理想信道模型。COOJA(Contiki OS Java)作為近年來新推出的無線傳感網(wǎng)仿真平臺,可以高效的仿真上百節(jié)點的無線傳感網(wǎng)絡(luò),但由于其信道模型并不能很好的反映真實環(huán)境中無線信道衰落特性,研究開發(fā)適用無線傳感網(wǎng)應(yīng)用環(huán)境的信道模型顯得尤為重要。本文首先介紹了無線信道模型的研究進展和應(yīng)用情況,分析COOJA中信道模型存在的不足,提出開發(fā)集成新的信道模型的可能性。研究了目前已有的基于實測數(shù)據(jù)統(tǒng)計規(guī)律建立的經(jīng)典信道模型,分析它們各自適用的場景特點。本文分別從大尺度衰落和小尺度衰落兩方面,研究設(shè)計適用于無線傳感網(wǎng)應(yīng)用環(huán)境的信道模型。小尺度衰落中,當信道存在視距傳播時接收信號服從Rice分布,結(jié)合Clarke模型和Jakes的簡化思想構(gòu)建Rice信道模型,仿真驗證了該思想具有服從萊斯分布的統(tǒng)計特性、良好的平穩(wěn)性和各態(tài)歷經(jīng)性且具有計算量小的特點。大尺度衰落基于對數(shù)路徑損耗,采用Plane-Earth模型,通過與實測雙斜率模型在不同環(huán)境中的對比,給出修正,并分析了它的適用條件。最終分別設(shè)計了適應(yīng)五種不同環(huán)境的信道:平坦水泥地、平坦沙地、平坦草地、低灌木叢、森林環(huán)境,但由于后兩種環(huán)境中會受視距分量存在與否的影響,Plane-Earth模型不能統(tǒng)一描述,因而后兩種環(huán)境使用單斜率模型。最后,在深入研究大無規(guī)模仿真平臺COOJA的架構(gòu)和仿真機制的基礎(chǔ)上,使用Java語言設(shè)計并實現(xiàn)五種信道模型,完成信號強度預(yù)測、誤包率計算等功能,為物理層提供信號強度指示和數(shù)據(jù)包接收判斷。將信道模型集成在COOJA仿真平臺中與原有信道對比,在預(yù)測值的比較上,原有信道預(yù)測模型預(yù)測值存在較大的差異;在仿真性能方面,通過建立500節(jié)點的無線傳感網(wǎng)仿真場景,由于新的信道模型計算復(fù)雜度更高,總體仿真效率略有降低,但信道模型預(yù)測更具有合理性,可用于未來COOJA無線傳感網(wǎng)絡(luò)仿真的信道模型選擇之一。
[Abstract]:Wireless sensor network is composed of nodes randomly distributed in monitoring area, which can be used in environmental monitoring, military, industrial control and other fields. The size and complexity of nodes in the network increase with the demand of wireless sensor network monitoring application. The requirements of simulation tools for large-scale wireless sensor networks are becoming higher and higher. The complex wireless channels make the communication links between nodes have randomness and instability, which directly affect the network simulation evaluation. In the previous research of wireless sensor networks, Focusing on protocol and energy consumption, the channel design is mostly based on the ideal channel model. COOJAN Contiki OS Java) as a newly developed wireless sensor network simulation platform in recent years, it can efficiently simulate hundreds of nodes of wireless sensor networks. However, the channel model can not well reflect the fading characteristics of wireless channel in real environment. It is very important to develop the channel model suitable for wireless sensor network application environment. Firstly, this paper introduces the research progress and application of wireless channel model, and analyzes the shortcomings of channel model in COOJA. The possibility of developing and integrating new channel models is put forward, and the classical channel models based on the statistical law of measured data are studied. In this paper, the channel models suitable for wireless sensor network application environment are studied and designed from the aspects of large-scale fading and small-scale fading respectively. When the channel exists the line-of-sight propagation, the received signal is distributed according to the Rice. Combining with the Clarke model and the simplified idea of Jakes, the Rice channel model is constructed. The simulation results show that the proposed method has the statistical characteristics of the slave Rice distribution. The large scale fading is based on logarithmic path loss, the Plane-Earth model is adopted and compared with the measured double slope model in different environments. Finally, the channel for five different environments is designed: flat cement land, flat sand land, flat grassland, low bush, forest environment, etc. However, the Plane-Earth model can not be described uniformly in the latter two environments because of the influence of the presence or not of the line-of-sight component, so the latter two environments use a single slope model. Finally, based on the in-depth study of the architecture and simulation mechanism of the large scale simulation platform COOJA, Five channel models are designed and implemented by using Java language. The functions of signal strength prediction and packet error rate calculation are completed. The channel model is integrated into the COOJA simulation platform and compared with the original channel. In comparison with the original channel, the prediction value of the original channel prediction model is quite different. In terms of simulation performance, through the establishment of a 500-node wireless sensor network simulation scene, due to the higher computational complexity of the new channel model, the overall simulation efficiency is slightly reduced, but the channel model prediction is more reasonable. One of the channel models that can be used in future COOJA wireless sensor network simulation.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.5;TP212.9

【參考文獻】

相關(guān)期刊論文 前1條

1 楊浩;桑林;;瑞利衰落信道Jakes模型的研究與性能分析[J];現(xiàn)代電信科技;2012年08期

相關(guān)碩士學(xué)位論文 前2條

1 孫剛;無線傳播信道模型庫的研究與建立[D];西安電子科技大學(xué);2009年

2 秦念慶;基于RSSI的無線傳感器網(wǎng)絡(luò)多邊定位算法研究[D];山東大學(xué);2009年

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本文編號：1592899