臺灣博碩士論文加值系統

近年來，由於物聯網應用之興起，異質網路的問題越來越受到重視，其中，又以WiFi與ZigBee網路受到最多的關注。在這兩個網路共存的環境中，ZigBee網路處於傳輸弱勢，將會難以傳送資料，這將使緊急事件無法透過ZigBee即時回傳並處理，而耽誤救援的行動。本論文提出一運行於ZigBee與WiFi網路之共存媒介傳輸協定，除了能有效解決兩個網路間的干擾問題外，還針對緊急事件的發生做出應對，以加快緊急資料的傳遞速度。實驗模擬顯示，本論文所提出的協定可有效減少ZigBee與WiFi網路間的干擾行為，並降低ZigBee網路的傳輸延遲。

The network lifetime of Wireless Sensor Networks (WSNs) highly depends on the remaining energy of each sensor. However, the irregular location and frequency of the event detection leads to different remaining energy of each sensor when all the sensors execute their task for a long time. As a result, some sensor may exhaust its energy, resulting in coverage hole. Therefore, to fully cover the hole, each sensor should move to cover the hole for achieving the purpose of full coverage. Nevertheless, the sensor which has the least energy may exhaust its energy earliest and hence the coverage hole will be created. This paper takes into consideration the remaining energy of each sensor. Then, the proposed Weighted Voronoi Diagram will be constructed for determining each sensor’s monitoring area based on the remaining energy of each sensor to achieve the energy-balancing and full coverage.

目錄
圖目錄 VI
表目錄 VIII
第一章、 簡介 1
第二章、 背景知識:IEEE 802.11和IEEE 802.15.4標準 5
2.1 IEEE 802.11/WiFi 5
2.2 IEEE 802.15.4/ZigBee 9
第三章、 網路環境與問題描述 14
3.1 網路環境 14
3.2 問題描述 15
第四章、 針對緊急訊息之共存網路協定 22
4.1 ZigBee網路初始化 22
4.2 ZigBee與WiFi異質網路共存之傳輸架構 26
4.3 ZigBee網路緊急訊息傳輸機制(ETM) 28
4.3.1 計算最短的Superframe長度 30
4.3.2 一般模式 ETM-N運行機制 34
4.3.3 緊急模式ETM-E運行機制 38
第五章、 模擬分析 43
5.1 網路環境 43
5.2 網路平均吞吐量 45
5.3 平均網路點對點傳輸延遲 50
5.4 平均網路電量消耗 52
5.5 平均網路封包遺失率 54
第六章、 結論 57
參考文獻 58
附錄-英文論文 62

圖目錄
圖 一、WiFi的超級訊框架構 6
圖 二、WiFi的PCF傳輸模式 7
圖 三、WiFi的DCF傳輸模式 8
圖 四、ZigBee的多跳傳輸模式示意圖 11
圖 五、ZigBee的超級訊框架構 13
圖 六、網路場景圖 15
圖 七、ZigBee網路中的一個Superframe會被切分成c個等長的Active windows 23
圖 八、兩相異ZigBee網路初始化方法完成後之傳輸效能比較 25
圖 九、ZigBee與WiFi異質網路共存之傳輸架構 28
圖 十、IEEE 802.15.4中Superframe與Active window之關係圖 31
圖 十一、ZigBee網路的多跳傳輸 35
圖 十二、ETM-N運作機制 36
圖 十三、WiFi與ZigBee在ETM-N中之對應排程 38
圖 十四、ETM-E運作機制 39
圖 十五、ETM-N與ETM-E之頻寬資源分配 41
圖 十六、不同場景中閘道器與ZigBee位置的分佈方式 45
圖 十七、不同場景中ZigBee裝置個數與網路平均吞吐量關係 48
圖 十八、不同場景中緊急封包生成速率與網路平均吞吐量關係 50
圖 十九、不同場景中ZigBee裝置個數與網路平均hop數對網路平均點對點傳輸延遲之影響 52
圖 二十、緊急事件區間與ZigBee裝置個數對網路平均電量消耗的影響 54
圖 二十一、不同ZigBee裝置個數時，封包存活時效與緊急封包生成速率對平均網路封包遺失率的影響。 56

表目錄
表 一、符號表 16
表 二、ETM-N與ETM-E之特性比較表 41
表 三、ZigBee與WiFi相關參數 43

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