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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/6051

Title: 無線隨意網路中一個新的頻道跳躍媒體存取控制層協定
A New Channel Hopping MAC Protocol for Ad-Hoc Networks
Authors: Kuan-Ju Huang
Contributors: NTOU:Department of Computer Science and Engineering
Keywords: 無線隨意網路;IEEE 802.11;多頻道;媒體存取控制;Quorum
Ad-Hoc;IEEE 802.11;Multi-Channel;MAC;Quorum
Date: 2007
Issue Date: 2011-06-22T08:42:39Z
Abstract: IEEE 802.11標準中的實體層允許節點透過多個頻道傳送資料,但媒體存取控制層卻設計為只能使用一個頻道。利用多個頻道可增加空間的利用度和降低封包碰撞的機率,並增加網路的吞吐量。設計多頻道媒體存取控制層協定時比設計單一頻道的協定要困難許多,有些新的問題需要克服,例如多個頻道如何配置、多頻道隱藏節點問題和找不到接收者問題。現有的多頻道媒體存取控制協定有硬體成本太高或是太長的延遲時間的缺點。在本論文中,我們提出一個分散式頻道跳躍的多頻道媒體存取控制協定,稱為Cyclic-Quorum-based Multi-Channel (CQM)。我們的方法有幾個優點:(1) 每個節點僅需具備一個傳輸器即可保證傳送者和接收者能在同時間切換到同一頻道。(2) 節點的頻道跳躍方式由自己的節點編號決定,可降低交換控制訊息的負擔,例如可省去傳送可用的頻道資訊和各節點跳躍的序列等控制訊息。(3) 節點彼此互相碰面的機率比現存的頻道跳躍協定高,成功傳送封包的延遲時間相對的降低。我們提出的方法是簡單而且有效率的。從模擬的結果也證明我們的方法適合用在多頻道無線隨意網路的媒體存取控制協定。
Although multiple channels are supported in the physical layer, the IEEE 802.11 MAC layer mechanism is designed for using a single channel. Exploiting multiple channels enhances spatial reuse and reduces transmission collisions and thus improves network throughput. Designing a multi-channel MAC protocol is much difficult than designing a single-channel one. New challenges, such as the channel allocation problem, and the missing receiver problem, must be overcome. Existing multi-channel MAC protocols suffer from either higher hardware cost (because of applying multiple transceivers) or longer packet delivery latency (due to limited transmission opportunity). In this thesis, a fully distributed channel hopping solution, the Cyclic-Quorum-based Multi-Channel (CQM) MAC protocol, is proposed. The advantages of the proposed protocol are threefold: i) Each node is equipped with a single transceiver and any sender is still guaranteed to meet its receiver in a short time. ii) Each node's channel hopping sequence is derived from its node ID. The overhead of exchanging control messages, such as each node's hopping sequence or available channel list, can be reduced). iii) The packet transmission delay is reduced, compared with existing channel hopping protocols, since the meeting probability of each tansmission pair is increased. The proposed protocol is simple and efficient. Simulations results verify that our mechanism is a promising multi-channel MAC protocol for ad-hoc networks.
URI: http://ethesys.lib.ntou.edu.tw/cdrfb3/record/#G0M95570031
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