本論文提出FQEC（Fuzzy quorum-based energy conserving protocol），它是一個省電的通訊協定，適用於隨意型網路（Ad hoc wireless network）。在IEEE 802.11標準協定之省電模式中，無論是否有資料要傳送/接收，行動節點都必須週期性地在每一個Beacon interval都醒來，這樣的機制無法達到最佳的省電效果。Quorum理論應用於IEEE 802.11的省電模式上可以使行動節點在僅有少量資料需傳輸時，可連續多個Beacon interval都進入省電模式，同時保證在一段時間內各行動節點之間的通訊聯繫不會中斷。利用Quorum理論來達到省電目的時候，Quorum表格的大小是整個效能表現的重要關鍵。本論文的研究重點，即是考量行動節點的傳輸狀況，包含行動節點收到的封包之傳送延遲時間和緩衝區未傳送的封包之等待時間，透過模糊控制系統的運作，動態調整行動節點所使用的Quorum表格大小，讓行動節點可以保存更多的電量，模擬結果顯示FQEC可在僅增加少量的傳送延遲時間下，大幅改善省電效能。 We propose a power-saving protocol, fuzzy quorum-based energy conserving protocol (FQEC), for IEEE 802.11 ad hoc networks. In the IEEE 802.11 power saving mode, hosts have to wake up every beacon interval to check if they have to remain awake in the remaining of that beacon interval. It is not an optimal power-saving solution since a host with no little traffic also has to wake up every beacon interval. With the quorum-based energy conserving protocol (QEC), it is possible for low-traffic hosts to sleep for several successive beacon intervals to reduce power consumption. In QEC, the quorum size plays an important role in performance. In this paper, we investigate the possibility to use a fuzzy control system to dynamically adjust the quorum size in order to conserve more energy. In the fuzzy control system, we define the control rules according to the experienced latency of both incoming and outgoing packets. Simulation results show that our FQEC achieves significant energy conservation at the expense of slightly increased latency.
