在本論文中，我們提出了一個改善的時槽保留機制，可以有效的減少緊急安全訊息傳遞的延遲。本論文所提出之作法中，每台車會從自己的鄰居車輛中，挑選一台車當作轉傳車，並且使自己的保留時槽與轉傳車的保留時槽盡可能的相近，從模擬結果可以看出，本論文所提出之作法與文獻中其他的TDMA做法相比，本論文所提出之作法可以有效的減少緊急安全訊息傳遞的延遲。另外，在DSRC的架構下，以群集為基礎的多通道通訊機制先前已被提出，它包含了免競爭與競爭的MAC協定，為了改善非即時訊息的多通道配置，本論文提出了一個混合通道配置的架構，我們使通道的選擇不再是根據區域性的資訊而是根據全域性的，這樣做可以有效率的配置通道且避開隱藏節點的問題。

In this thesis, an improved slot reservation scheme is proposed that can effectively reduce the transmission delay of emergency safety messages. In our proposed scheme, each vehicle must first choose one vehicle from its neighbors as its transfer vehicle, and then makes its slot reservation as close as possible to the reserved slot of its transfer vehicle. It is shown from simulation results that our proposed scheme can effectively improve the transmission delay of emergency safety messages than other TDMA approaches proposed previously in the literature. In addition, under the DSRC architecture, a cluster-based multichannel communications scheme has been proposed previously, which integrates the clustering with contention-free/ contention-based MAC protocols. In order to improve channel utilization for non-real-time data transmissions, a hybrid channel allocation scheme is proposed in this paper, in which the channel selection is determined not only locally, but also globally. This helps to efficiently utilize the data channels, while preventing from hidden terminal problems.

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