IEEE 802.11p/1609標準將頻率分割為一個控制頻道(CCH)及六個服務頻道(SCH)。車機及路邊裝置等車載裝置可於CCH傳輸緊急及控制訊息，且於SCH傳輸服務應用訊息。許多學者提出頻道存取機制以改善CCH頻寬效能。這些機制採用競爭方式來取得頻寬使得CCH遭遇嚴重的封包碰撞，或消耗過多的頻寬負載來取得CCH頻寬，進而降低CCH的產出。因此，本篇論文提出群組式保留之媒體存取控制 (Group Reservation MAC, GRMAC) 協定，以群組之頻寬保留機制，讓車載裝置可於SCH中保留CCH頻寬，以減少CCH中封包發生碰撞的次數，並且將頻寬排程機制由CCH移轉到SCH以減輕CCH執行頻寬排程的負擔，進而提升CCH頻寬效能。模擬結果顯示，在高負載的情況下，GRMAC之有效吞吐量(goodput)優於IEEE 802.11p/1609機制約2倍。

IEEE 802.11p/1609 standards divide the radio spectrum into one control channel (CCH) and six service channels (SCHs) for the emergent/management packet exchange and the service dissemination, respectively. In order to improve the goodput on CCH, many channel access schemes have been proposed. These schemes, however, suffer enormous collisions or consume large overhead on CCH, leading toward poor goodput. In this thesis, Group Reservation MAC (GRMAC) is proposed to minimize the collisions occurred on CCH and thus to increase the overall goodput of CCH. GRMAC lets the vehicles reserve the CCH bandwidth on SCHs in order to alleviate the collisions on CCH. Also GRMAC transfers the CCH bandwidth scheduling mechanism from CCH to SCHs for lightening the burden of CCH bandwidth resource. The simulation results under a heavy load indicate that GRMAC achieve 2 times the goodput achieved by conventional IEEE 802.11p/1609 mechanism.

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