臺灣博碩士論文加值系統

在無線感測器網路中，感測器的電力供應是有限的。考量到節約能源消耗，Tmote Sky 感測器提供可調整的傳輸功率，使用者能夠依照各個感測器所需的傳輸距離來設定。然而在實際環境中，因為障礙物或是其他無線訊號的干擾，感測器的傳輸距離受到影響，因而通訊不時中斷。
為了解決這個問題，本篇論文提出三種改進方法，當感測器偵測到通訊中斷，它們能夠暫時的加大傳輸功率，向備用的感測器請求幫助，或是廣播控制訊息以互相協助。實驗結果顯示以上的改進方法可以提升Tmote Sky 感測器網路的連接品質，同時又不會造成太多額外的電量負擔。

Tmote Sky sensors provide programmable and adjustable output power for transmission. Users can control needed transmission power for each sensor. However, the transmission range for a fixed power changes inconsistently due to the interferences, such as obstacles and other wireless signals. Therefore, the communication between sensors is disconnected sometimes. To solve the problem, this thesis demonstrates the implementation of three recovery schemes. As Tmote Sky sensors detect communication disconnection, sensors will increase their transmission power for a certain of time, ask backup nodes for help, or broadcast control messages for cooperation. Practical experimental results reveal the amount of lost packets can be reduced with a little additional energy.

Chapter
1. Introduction : 1
2. Observation: Intermittent Disconnections : 4
3. System Model : 8
4. Solutions : 11
5. Experiments : 15
5.1 Transmission Performance : 17
5.2 Energy Consumption : 18
6. Conclusion and Future Work : 23
6.1 Conclusion : 23
6.2 Future Work : 24
References : 25
Vita : 27

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