近年來無線網路通訊已經越來越普遍了，所以許多人慢慢的都投入這方面的研究。ad hoc 網路正是其中的一種，它是全由無線裝置所建構而成的網路，每個行動主機可隨意移動，且兼具 router 的角色，幫忙網路上的其它節點做封包轉送的動作。由於它不需要事先的基礎建設，因此在救災或是戰場等方面特別具有應用價值。由於這種網路的一些先天上的特性，例如電力無法持久，以及網路頻寬不足等因素，因此在這種網路上，為了能夠減少電力的消耗，以及頻寬的浪費，許多應用大多是採用群播的方式來完成，所以群播繞路演算法的設計，就顯得相當重要。

　　在ad hoc 無線網路裡，行動主機常常隨意移動，造成建立好的路徑容易斷裂，使得需要不斷的重建群播樹，許多已經提出的網路層的群播繞路演算法，都有這種缺點，所以後來的研究，大都往應用層的群播方面發展。 在本篇論文中，將考量 power 消耗的因素，並利用叢集技術，使得網路存活時間能夠較長，同時採用在叢集中，有 backup leader 的作法，使得叢集在失去 leader時，能在很短的時間內，讓中斷的資料傳輸能迅速的回復到繼續傳送的狀態。

　In recent years, wireless communication has been more and more widespread. A lot of people research and development efforts focused on this side gradually. Ad hoc network is one kind of these wireless networks. It is organized by a collection of wireless devices. Each mobile host can move arbitrarily and functions as a router, offering packet-forwarding services to all other nodes in the network. Because any pre-established wired or wireless infrastructures are unnecessary. Therefore it is very important and useful in the region without base stations supporting, such as in disaster and battlefield area.

　Ad hoc network has some natural characters. For instance, the power can not persist a period of long time. Secondly, the network bandwidth is not large enough. Many applications are accomplished by using multicast in order to reduce the power consumption and save the bandwidth. Therefore, design of the multicast algorithm is very important.

　In ad hoc network, mobile hosts often move arbitrarily and the link is fragile. This make the multicast tree rebuild frequently. Most of the existing multicast routing protocols in network layer have this kind of drawback. Hence, current research focused on application layer multicast. In this paper, we will employ the clustering technique and consider the factor of power consumption to increase the network lifetime. We also use a backup leader in the cluster to repair the structure when the cluster leader is disappeared. As a result, that will make the interruption of the data transmission can be recovery in a short time.

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