本計畫將提出一個在多重通道感知無線隨意網路環境中具能源效率與高輸出量之媒介存取協定。藉由考慮降低PU干擾及提升SU通道使用率達到提升系統輸出量的目的，為達到此目的及降低對隱藏節點PUs及SUs的干擾；並同時解決暴露節點SU問題，提出動態長度之競爭視窗大小及SU傳送端持續佔有多個資料時槽機制。此競爭視窗包含四個控制訊框，控制訊框時槽長度將由SU所感測到PU空閒的資料通道個數及SU競爭節點個數多寡所共同決定。如果所有控制訊框時槽長度都是固定時，當設定值太大時，在SU低負載的情況時，將導致系統浪費較長時間在等待競爭週期的結束；當設定值太小時，在SU高負載的情況時，將導致系統因競爭情況加劇，使碰撞所導致的隱藏節點問題更形嚴重而大大降低系統效能。而為了延長整個網路生命週期，藉由計算SU傳送端所剩餘的能量多寡來決定是否持續佔有多個資料通道時槽，並提升系統輸出量。本研究方法也將與先前的方法比較，證明本計畫所提出來的方法，確實比先前的方法更能節省系統節點能量及提升系統輸出量。 In this proposal, we propose an Energy Efficient and High Throughput MAC (EEHT-MAC) protocol in multichannel Cognitive Radio Ad Hoc Networks (CRAHNs), to solve the hidden and exposed terminal problems of multichannel PUs and SUs. To improve the system throughput by reduce the interference to PUs and increase the channel utilization of SUs. We propose the dynamic length of contention window and permit the SU sender to reserve multiple data slots to solve the hidden and exposed terminal problems between PUs and SUs. Too longer length in contention window, the SUs must wait more time on contention window under lower load. In contrast, too shorter length in contention window, the contention and hidden terminal problems will be serious under higher load. In order to increase the network life time and fairness, the low power of SU sender can reserve multiple data slots. We also compare our proposed scheme to existing MAC protocols for CRAHNs. We will show that EEHT-MAC has higher power efficiency and system throughput than previous MAC protocols.
