Wireless Sensor Networks已廣泛地應用在軍事用途、目標追蹤及環境監測。然而，Sensor Node在經過長時間的環境感測下，可能因為電量耗盡、訊號的干擾或是其他的外力因素，使其喪失環境感測的能力，導致在Wireless Sensor Networks環境中形成感測上的空洞區，並逐漸擴大影響範圍而使得網路形成斷裂的情形，進而使一些Sensor Nodes雖能正確的感測到資料卻無法將訊息回傳給Sink Node，影響資料收集的精確度。因此在本論文中，我們將針對網路斷裂的產生，提出一個預先偵測及預防的方法。在網路因空洞而導致斷裂分割前，我們針對成長中的空洞進行偵測及監控，並利用資料Aggregation的特性來監控空洞是否讓網路進入不安全(Unsafe)狀態，避免可能發生的網路斷路。 除此之外，本論文也提出一個網路修復的機制，在網路斷裂前利用Mobile Sensor予以修復。在本論文中，我們所設計的網路斷裂偵測及修復機制，不但能以分散式的方式，偵測感測空洞的大小與形狀，並且預測空洞的成長，在其造成網路斷裂前，找出最符合成本效益之修補路徑，並以WSNs所提供的有限的Mobile Nodes依循演算法所找出的最佳路徑，進行修復感測空洞的任務，使Wireless Sensor Network回復正常的感測及資料回傳的能力。 經由本論文的實驗數據顯示，本論文所提出的障礙物處理通訊協定，不但能有效地在Wireless Sensor Network中預防因空洞所造成的網路斷裂情形，並且能確保所有感測的訊息都能成功的回傳至資料收集點。 Wireless Sensor Network (WSN) is one kind of wireless network system which comprised with a sink node and a number of sensor nodes. The main purpose of WSN is to monitor and to track every single movement in a specific area. Sensor nodes are deployed density in the network and transmit the gathered information to sink node in a multi-hop manner. Therefore, some sensor nodes tend to exhaust their energy more easily than other nodes due to their heavy traffic load on packet forwarding. In wireless sensor network environment, network partition is a frequent phenomenon which could make the seasoning data much less preciously. Therefore, WSN need a partition detection mechanism to mark the “Undetected Area” and bypass this area when forwarding message to sink node. This paper proposes an efficient Partition Detection and Avoidance Protocol to detect the network undetected area, to avoid network partition phenomenon and to extend the sensor network life time. According the experiments of this paper, simulation results shows that the developed partition detection and avoidance protocols can efficiently detect and monitor the obstacle to prevent network partition and keep network always connected, Moreover, It could indeed extend the sensor network lifetime.
