收集感測器所偵測到的資料(Data Collecting)為無線感測網路(WSNs)中一重要的研究議題。傳統以樹狀拓樸當作資料收集的繞徑方式，在Sink附近的感測器會因過度地幫助其他感測器代傳資料，導致電量過度消耗而提早死亡。為了解決此問題，一些文獻利用Mobile Sink在監控區中移動並收集資料[1][2][3][4]，將傳遞封包的工作盡量分給較多的感測器來共同承擔，以減輕感測器的負擔。然而，其電量平衡的程度仍可改善。本論文針對圓形監控區擬研發一讓感測器電量平衡之資料收集制，利用Mobile Sink在多個環狀軌道中行走，透過耗電量的評估，計算出Mobile Sink 移動的路徑軌跡，以達到全區電量平衡。實驗結果顯示，本論文所提出之資料收集技術確實可平衡監控區中所有感測器之電量消耗，且達到延長整個感測網路之生命期的目標。 Data collection problem is one of the important issues in Wireless Sensor Networks (WSNs). Constructing a tree from all sensor nodes to the sink node is the simplest way for data collection but raises the energy unbalance problem where nodes closer to sink has heavier data-relaying workload and thus exhaust their energy earlier. To cope with the energy balancing problem, a number of mobile-sink mechanisms have been proposed that change the location of mobile sink for migrating the workload of data relaying from one sensor to another. However, the efficiency of energy balancing can be further improved. This paper proposes an energy-balanced data-collection mechanism which determines the movement trajectory of mobile sink such that the data relaying workloads of all sensors can be totally balanced. Performance study reveals that the proposed mechanism can balance the energy consumptions of all sensors and thus prolong the network lifetime.
