在隨意型無線網路（Mobile Ad hoc Network，MANET）中，無線網路的壽命依賴於行動端點的電池能量，所以能量保存是一個很重要的課題，因此我們期望設計出一個可相容於現今的IEEE 802.11 協定，並且能有效節省耗電量的新協定。在IEEE 802.11 DCF 模式下的能量保存模式（Power Saving Mode）中，每個行動端點必須週期性地醒來，以判斷是否有傳送或接收的動作產生。然而這種方式需要週期性醒來，因此省電效率並不是很好。本篇論文提出一個嶄新並更加省電的協定，此方法可以增加電池能量的耐久性，進而延長行動端點與網路的壽命，同時也相容於現今的IEEE 802.11 協定。此協定是藉由Quorum 的特性，使每個行動端點不需要在每個週期醒來，但仍然可以經由彼此交集而達到互相通訊的效果，並且延長連續睡眠時間以達到省電的效果。模擬的結果指出這個新的能量保存協定的延遲時間會較長，但可以延長整個MANET 的網路壽命。 The lifetime of a mobile ad hoc network (MANET) depends on the durability of the battery resource of mobile hosts. In IEEE 802.11 Power Saving Mode, a mobile host must wake up in every beacon interval to check if it needs to remain awake for that particular beacon interval. Such a scheme fails to adjust a mobile host’s sleep duration according to its traffic thereby reducing its power efficiency. This paper presents the new MAC protocols for power saving in a MANET. The essence of these protocols is a quorum-based sleep/wake-up mechanism which conserves energy by allowing mobile hosts to sleep more than one beacon interval, if they involve a few transmissions. The proposed protocols are simple and compatible to the IEEE 802.11 standard. Simulation results show that our protocols conserve more energy and extend the lifetime of a MANET without increasing packet loss ratio.
