車用網路中，車與車之間通訊使用單一頻道並用於娛樂用途(大量影音傳輸)時容易產生頻道壅塞。若使用多頻道則可減少無線傳輸中單一頻道之干擾，並且在不同傳輸組合中可同時進行資訊的傳輸。但在多頻道環境下，車與車間需要共通頻道做為協調資訊傳輸通道之用。若協調機制使用特定共通頻道，則有機會產生通道壅塞而降低協調機制之效率。我們提出一種多頻道通訊協定於媒體存取控制層，並應用法定人數集合系統(Quorum system)來設計分散式的共通多頻道協調機制。由於法定人數集合系統可讓不同系統集合間必定存有一交集元素，我們將頻道對應至系統之任一集合可達到分散式共通頻道之效果。透過法定人數集合系統，車間通訊可以平均且完整使用所有頻道以利於資料傳輸。模擬結果中顯示此方法相較於其它多通道通訊協定有著更為良好的頻道使用率，並能提供較為快速的協調機制完成時間。

To improve throughput and reduce channel contention over inter-vehicle communication in vehicular ad-hoc networks (VANETs), wireless communication devices should effectively and efficiently utilize multiple channels dedicated to VANETs. To this end, we propose a multiple-channel MAC protocol which aims to fully and uniformly utilize all available channels in a random-access manner, considering the constraint that a device has only one or a small number of antennas (radio interfaces). In a wireless network where there are channels than radio interfaces on a device, a sender has to finds out a common channel before negotiating/selecting a channel used later for data transmission to the receiver. We design two different mechanisms for the cases with different numbers of radio interfaces, based on the concept of quorum system. The simulation result shows that compared with other protocols, our quorum-based protocol has either higher system throughput or shorter negotiation duration.

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