| 摘要: | 近年來，發展多頻道媒體存取協定已受到極大的關注與討論，並被認為是開發頻寬利用率最有效的方法。在發展多頻道通訊協定時所遭遇的最大挑戰便是主機會面問題(Rendezvous Problem)與多頻道隱藏主機節點問題(Multi-Channel Hidden Terminal Problem)。在過去的研究中，為會面問題，使所有主機在一相同的窄頻會面，造成同時段其它頻道的頻寬利用率降低。本論文提出一多頻道MAC協定，以階梯式的頻道模型及Home Channel概念，不但解決多頻道的主機會面與多頻道隱藏主機節點問題，並將會面的主機平均打散在各個頻道與時間，充份利用頻寬資源以增加網路吞吐量。實驗顯示，本論文所提出的協定可有效增加頻寬利用率，並提昇網路效能。
Multi-channel MAC protocols aim to exploit frequency resources for increasing the overall throughput of wireless Ad-Hoc networks. The most common challenge for developing the multi-channel MAC protocols is the well-known rendezvous problem. In literature, some studies assumed that each device equips with one additional antenna, staying on the control channel for negotiating the channel for data exchange. However, the hardware cost has been increased. Some other works ask all devices participating in ATIM window of a predefined channel, competing for the reservation of data slots for data exchange. However, the bandwidth utilization is low since the ATIM window of all channels other than the predefined channel are not used. This paper presents an Advanced Stepwise Multi-channel MAC Protocols, called ASMC-MAC, for the Wireless Ad Hoc Networks. The proposed ASMC-MAC is developed based upon single antenna and applies stepwise channel model with home channel concept to exploit the multi-channel bandwidth resource. Performance results reveal that the proposed ASMC-MAC outperforms existing multi-channel MAC protocols in terms of network throughput, packet collision ratio, packet delay time, packet discarding, and fairness index. |