隨著技術的不斷發展，現今軟體對網路頻寬的需求也日益增加。為了增加無線網路的競爭力，改善其頻寬不足的缺點就成了一個重要的課題。
由於依IEEE 802.11中所訂定的媒介擷取控制通訊協定(medium access control protocol)，對每個頻道(channel)的使用上顯得很沒有效率，因此，這多研究紛紛朝向如何更有效的去利用每個頻道上去發展。但由於受限於每個頻道本身的頻寬限制，這類的方法無法為無線網路帶來大幅度的進步。因此，我們轉而傾向從多頻道的利用上著手。
在標準裡，訂定了許多的頻道。但是，目前每次都只會使用一個頻道，而讓其他的頻道就閒置在旁。這無疑是一種浪費。若我們可以同時利用多個頻道，在網路中就能有更多的傳輸可以同時進行。如此一來，就可以有效的提升網路的容量和傳輸速度。
在這篇論文中，我們提出了一個供為無線隨意網路(Wireless Ad Hoc Network)使用的媒介擷取控制通訊協訂。在我們的方法中，每個節點(node)都只需要配備一個無線電收發器(transceiver)就可以有效的利用多頻道，而且可以避免掉在多頻寬的環境下，所常會發生的問題，如：新多頻道隱藏工作站(new multi-channel hidden terminal)問題。
我們對頻道的使用是採動態的方式，網路中的每個節點(node)有資料要傳輸的時候，就會主動跟他的接收端去協調，互相協商出一個理想的頻道做為之後資料的傳輸使用，並且會向周圍的節點做保留的動作。而在使用完了之後，會將這個頻道的使用權重新交還出來，讓其他的節點可以利用，而不會永久的佔據這個頻道。
除此之外，我們更進一步提出了一個方法，可以依據當時的網路情況去動態的調整我們所提出的媒介擷取控制通訊協定，使其能依不同的網路情形，發揮出最好的效能。
實驗的結果也顯示，這個方法可以大幅度的提昇網路整體的吞吐量(network throughput)。而我們所提出的動態調整的方法，也得確可以配合網路當時的情況，更進一步的改善原有通訊協定的效能，盡所能的確保每一個頻道都能有效的被使用。

Employing multiple channels is an effective way to improve the performance of wireless networks [2-15]. Some previous works on multiple channels [3-5] assume at least two transceivers and result in a higher cost on hardware requirements. The protocol in [6] uses a single transceiver and divides the beacon interval into two parts: channel negotiation and data transmission. However, the fixed length of channel negotiation interval limits the channel utilization. This paper proposed a new single transceiver MAC protocol that can exploit multiple channels effectively and dynamically adjust the length of negotiation interval to better utilize the wireless channel resources. The simulation results show that the proposed protocol achieves higher aggregate network throughput than the fixed schemes on various traffic loads.

第一章 簡介.............. 1
第二章 背景與相關研究.... 2
第三章 提出的方法........ 3
第四章 效能評估.......... 4
第五章 結語.............. 5

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