近年來，隨著可攜式電腦，包括筆記型電腦、個人數位助理，使用量的快速成長，帶動了無線網路的發展。而在無線網路架構中，以隨意網路具備了完全無線，可移動性及無任何基礎架構的特色，可在任何環境下組成區域性的無線通訊網路。然而現有的路由協定是以最小的跳躍點個數來選擇路徑，並不適用於隨意網路，所以我們使用鏈路存活時間取代跳躍點個數來選擇路徑。 在隨意網路裡，最主要的資料傳輸是群播。而在無線網路上的群播通常是用來散播重要及機密的資訊，因此在無線網路上的群播演算法必須確保其可靠性。但可靠群播會因為群播成員數量增加而造成來源端的負擔，所以我們利用協調者來減少來源端接收ACK的數量以及重送資料的負擔。 在本論文中，我們提出找尋協調者的方法以及可靠群播的流程。利用協調者及可靠群播流程，在足夠大的暫存器下，可以確保群播的可靠性。又我們分析了在不同的移動頻率下，協調者個數、控制訊息量及重送資料量的變化。最後我們預估暫存器的大小，以提供可靠群播來選定暫存器的大小。 Recently, the increase of the usage of portable devices, such as laptop computers, PDA, develops the wireless network. MANET (Mobile Ad Hoc Network) has the characteristics of complete wireless, mobility and non-infrastructure. It can deploy wireless LAN under any environment. However, present routing protocols, use the minimum hop count for route selection, are not suitable in MANET. So we suggest to use the link lifetime for route selection in our study. The most characteristic operation in MANET is multicast. Multicast operations in mobile networks are generally used for dissemination of important and confidential information. Multicast algorithms are hence expected to ensure a reliable message delivery. In reliable multicast, as the number of the group members grows, the number of ACK message increases dramatically. This leads to a heavy burden on source and causes more severe congestion and data losses in network. So coordinators are always used to reduce the number of ACK message and the burden on source. In this thesis, we propose a scheme to decide coordinators for reliable multicast. Using coordinators and this reliable multicast algorithm, we can ensure the reliability under the enough buffers. We analyze the variation of the number of the coordinators, the control messages and the retransmitted data under the different motion frequencies. The required buffer size is also estimated in our simulations.
