在無線網路環境中，工作站往往都是依靠電池來供電，因此如何有效率的使用電源、電池電力是ㄧ個重要的課題。在IEEE 802.11 PCF 操作模式，當裝置若有資料待傳送，則必須在整個Beacon interval 保持醒著的狀態，就算已經傳送完資料，仍舊不能進入睡眠模式，除非此期間無資料待傳送才能進入睡眠模式，因此仍有不必要的電力消耗。在本論文中，我們提出了一個改良的排程機制，稱作Adaptive Power Saving Mode，最佳的省電模式， 主要是把Beacon interval 分為 Beacon訊框+DTIM與Data window 兩個部份，而Data window 又會切割成數個相同長度的Time Slot，在Beacon訊框+DTIM期間，AP依資料量與電池剩餘量，依一定比例作Shortest first的排序，在Data Window 中工作站將依據AP的輪詢，傳送資料，因此當先傳送的裝置，傳送完資料即可進入睡眠模式，而不需要在整個Data window 都醒著，經由模擬結果發現(Adaptive PSM)，在Frame與Battery比例在30%70%可增加網路存活時間，進而延長電池使用時間，確實達到節省電源的消耗。 In the wireless network environment, the work stations always rely on the battery to supply power. So how to use power efficiently, the battery is an important subject. The operation mode of IEEE 802.11 PCF. If there have data be transacted by working station, must keep on the active mode in the whole Beacon interval, even it already finished transacting the data, it still can’t enter the sleeping mode. Unless there are not data waiting to transact and enter the sleeping mode during this interval. So there have unnecessary power consumption. In this Paper we put forward one improve arrange scheme . Call it as Adaptive Power Saving Mode. Mainly divide Beacon interval into Beacon +DTIM and data window two parts, and data window will be cut into Time Slot of several pieces of the same length. During Beacon+DTIM window, AP arranges the sequencing of shortest first depend on the frame size and remained battery. During data window the work station will to transact data follow this sequencing. So the working station can enter the sleeping mode when it finish transacting the data, and don’t need on active mode during the whole data window. Simulation result show that Adaptive PSM uses the proportion of Frame to Battery is 30%70% could increase the time of surviving of network. Then could lengthen battery service time, really reach of saving the power consumption.
