動態睡眠排程機制於非同步無線感測網路

Dynamic Sleep Scheduling in Asynchronous Wireless Sensor Networks

無線感測網路（Wireless Sensor Network, WSN）在能源消耗議題上一直是個很重要的研 究議題。為了確保無線感測網路在任何時候都 能有效率的運作，有眾多的睡眠排程機制被提 出來解決耗能的相關問題。其中在感測器中接 收與發送封包是最消耗能源的，因此透過使用 多媒體存取控制（Media Access Control, MAC） 協議控制每個感測節點睡眠排程，並使用睡眠 排程降低能源消耗，以提升每個節點的壽命。 在 X-MAC 機制中透過縮短 Preamble 的方法降 低能源的消耗，並降低每跳延遲。在 ContikiMAC 中則是嚴格的限制封包的長度並 藉由兩次的空閒通道評估機制（Clear Channel Assessment, CCA）來偵測頻道是否在忙碌。在 此論文中我們提出藉由許多程序和執行模擬 陣列，驗證我們所提出的機制優於傳統提供 XMAC 與 ContikiMAC 機制，並證明我們提出的 方法在有隱藏節點的情境下有顯著的增益。

The energy consumption issue is always an important research subject in wireless sensor networks (WSNs). To provide efficient operation, quite a few researches on sleep schedules related to energy issues have been proposed and discussed. By shortening the premable during media access control (MAC) period for sleep schedule control in the X-MAC scheme, the energy consumption of each WSN node has been reduced. Through the inter-space between two clear channel assessment, the ContikiMAC scheme detects and determines whether the channel is busy. In this paper, we conduct further process in the MAC contention period to improve the performance of energy consumption, especially for the hidden nodes scenarios.