IEEE 802.11無線網狀網路之分散式時槽分割式多重頻道協定

Abstract

IEEE 802.11 協定允許使用不同頻道來提升網路效能，儘管近年來有 不少這方面的研究，但分散式的分配頻道仍然是個複雜而具有挑戰性的問題。無線網路網路(Wireless Mesh Network)近年來倍受國際矚目，它提供有線區網的另一種更方便、更便宜的選擇，而在無線網狀網路上使用多重頻道(Multiple Channel)是非常吸引人的一個議題，因為無線網狀網路必需提供很大的頻寬給使用者。我們提出一個適合無線網路網路的鏈結層的多重頻道管理協定來增進整個網路的效能，這個協定使用已普及的IEEE 802.11 相容的網路卡介面，每個存取點只需一個介面便能順利運作，並且很容易能擴充至裝備多張介面卡的存取點。我們設計此協定使用接收端為主(Receiver-Based)的頻道分配演算法，並使用時槽來控制什麼時候該送、什麼時候該收。我們在真實的網路環境下實作這個協定來驗證我們方法，發現確實的提升了網路的吞吐量(Throughput)。

Multiple channels which are available for use in IEEE 802.11 can increase network capacity. Despite being the subject of many years of research, distributed channel assignment remains a challenging problem. The idea of exploiting multiple channels is particularly appealing in wireless mesh networks because of their high capacity requirements to support backbone traffic. We propose a link-layer protocol for wireless mesh network that utilizes multiple channels dynamically to improve performance. The protocol can be implemented in software over an IEEE 802.11-compliant wireless card. The protocol only needs one interface and can be easily extended to multiple interfaces. We design a receiver-based channel assignment algorithm and use time slot to control when to send and when to receive. Our protocol has been implemented in real environment and the result indeed shows improvement on the network performance.