在現今的感測網路應用下，進行資料收集時，節點對節點進行不使用Acknowledgement的傳輸資料是可被接受的；因此各節點於設定好的資料收集樹中，所應該使用的傳輸能量等級為足夠能將資料送至資料傳輸樹中的父節點即可。在此篇論文所討論的網路環境為所有sensor都採用可調整機制且彼此能互不相同的傳輸能量等級。在此情況下探討如何建立最大生命週期的資料收集樹。在我們所討論的網路中，由sensor所收集的資料在傳往base station的過程中，於各sensor皆會使用資料匯集方法將各個sensor的資料進行彙整。
在2010年Wu et al. 率先於網路環境定義為所有sensor都採用相同且固定的傳輸能量等級的情況下，計算出屬於此情況之最佳資料收集樹的生命週期倒數的最小底限並提出使用tree approach的approximation algorithm。在此篇論文中，我們對更普遍的網路環境也就是所有sensor都採用可調整機制且能互不相同的傳輸能量等級的情況，同樣的計算出於此情況下最佳資料收集樹的生命週期倒數之最小底限並且提出了在適合此情況下使用之tree approach的approximation algorithm。

In sensor network applications where data collection is acceptable or sufficient, hop-by-hop acknowledgement is not required for data delivery. The power level of each node on a data gathering tree can be adjusted to be just high enough to reach its parent node. This paper studies the problem of constructing maximum-lifetime data gathering trees in sensor networks in which the power levels of sensors are heterogeneous and adjustable. In-network data aggregation is also employed to aggregate sensor data while they are being forwarded toward the base station. This paper derives an upper bound on the lifetime of the optimal data gathering tree. For a given initial tree, an algorithm is developed to construct a data gathering tree by iteratively rearranging the current tree and improving the lifetime. Simulations are performed to study the performance of the algorithm.

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