數據收集是無線感測網絡（WSN）應用中最基本和重要的操作之一。最近的研究表明，使用移動感測器收集數據，為無線感測器網絡帶來了許多優勢，如提高感測器節點的能量效率和延長網絡壽命。但是，移動感測器的移動速度有限會導致數據傳輸延遲較高，或者無法保證每個感測器的數據都可以被完全收集。考慮到移動感測器構建最短路徑的需要，在提高數據採集效率的同時，提出了一種利用不同傳輸速率收集數據的算法。通過研究要移動的移動感測器的長度和數據收集的完整性來評估所提出的方案。通過大量的實驗，我們的方案結果表明，我們的方法可以顯著減少移動感測器移動路徑的長度，而每個感測器的數據可以被完整和有效地收集。

Data collection is one of the most fundamental and important operations in applications of wireless sensor networks (WSNs). Recent research has shown that using mobile sensor to collect data brings many advantages to WSNs, such as improving the energy efficiency of sensor nodes and prolonging network lifetime. However, the limited moving speed of Mobile sensors leads to a higher data transfer latency, or can’t guarantee that data of every sensor can be collected completely. Considering the need for mobile sensor to construct a shortest path, while improving the efficiency of data collection, we propose an algorithm of using different transmission rate to collect data in this paper. The proposed scheme is evaluated by investigating the length of the mobile sensor to move and the integrity of the data collection. Through extensive simulations, our scheme results show that our approach can notably reduce the length of the mobile sensor move path, while the data of every sensor can be collected completely and efficient.

Table of Contents
List of Figures	V
List of Tables	VI
Chapter 1. Introduction	- 1 -
Chapter 2. Related Works	- 6 -
Chapter 3. Problem Statement	- 14 -
3.1 Network Model	- 14 -
3.2 Problem Statement	- 15 -
Chapter 4. The Proposed Data Collection Path Algorithm	- 18 -
4.1 Initial Data Collecting Phase	- 19 -
4.2 Path Reduction Phase	- 21 -
4.3 Analyzes the length of the collection segment	- 24 -
Chapter 5. Performance Evaluation	- 32 -
Chapter 6. Conclusions	- 38 -
References	- 39 -
Appendix-Conference Version	-43-

List of Figures
Fig. 1. Constructed a path Pinit	- 20 -
Fig. 2. Constructed a path P	- 21 -
Fig. 3. Each group consists of three sensors	- 22 -
Fig. 4. The MCS applied in establishing the path segment for each sensor.	- 24 -
Fig. 5. Fully collect the data of sensor s2	- 28 -
Fig. 6. Constructed best path	- 29 -
Fig. 7. Construct Path Algorithm .	- 31 -
Fig. 8. The comparison of path lengths by applying Dense WSN scenario.	- 34 -
Fig. 9. The comparison of path lengths applying Distributed WSN scenario.	- 35 -
Fig. 10. The comparison of energy consumptions in the Dense WSN scenario.	- 36 -
Fig. 11. The comparison of energy consumptions in the Distributed WSN scenario	- 37 -

List of Tables
TABLE I. Modulation and Coding Scheme (MCS)	- 3 -
TABLE II. Simulation Setting	- 33 -

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