With the growth of group-oriented services over mobile ad-hoc networks, multicast routing protocols have attracted much attention recently. However, the conventional multicast
routing protocols generally suffer from frequent link breakage and high communication overhead, caused by node mobility and redundant routing paths respectively. To triumph over the problems, we propose a cooperative multicast routing protocol, COMRoute, which utilizes cross-layer design by physical-layer cooperative transmission, MAC-layer clustering, and network-layer multicast routing. Specifically, the physical-layer multinode decode-and-forward cooperative transmission provides reliable transmission links. At MAC layer, nodes are classified into clusters. This clustered architecture effectively mitigates the communication overhead. Based on the clustered architecture, we design an on-demand source-based multicast routing protocol at network layer, which takes diversity into account for route establishment, and thus provides robust network connectivity. Moreover, COMRoute solves an asymmetric cooperative transmission problem ignored by the previous researches. Our simulation results show that the proposed protocol outperforms the existing multicast protocols in terms of traffic overhead, delivery ratio, and
energy consumption.

隨著近年在行動隨意網路中的群組服務蓬勃發展，群播路由協定的設計也漸漸受到重視。傳統的群播路由協定通常受到節點移動造成的頻繁連結中斷及多餘路由路徑產生的高通訊負擔這些問題的影響，為了克服這些問題，本研究提出了一個合作式群播路由協定。合作式群播路由協定採用跨實體層、媒介存取控制層及網路層的設計。更詳細的說，實體層應用了多點解碼轉送合作式傳輸來提供可靠的連結；媒介存取控制層將網路節點分類為多個叢集，根據這樣的層級架構，合作式群播路由協定可以有效地減輕通訊負擔；在網路層，我們設計了一個被動式、基於源點的群播路由協定，此協定將多樣性加入路徑建立時的考量，因此可提供強健的網路連線。並且，合作式群播路由協定解決了一個以往研究忽略的非對稱合作式傳輸問題。實驗結果指出，合作式群播路由協定在訊息負擔，傳輸成功率及能源消耗上皆有優於傳統群播路由協定的表現。

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