| Summary: | 博士 === 國立臺灣大學 === 資訊工程學研究所 === 91 === An ad-hoc network is a temporary collection of a group of mobile nodes over wireless medium. Such network doesn’t rely on fixed base stations, but all mobile nodes have the ability of routing. Each node can forward data to the destination via other nodes. The network topology changes frequently due to the mobility of mobile nodes. The frequent changes of the network topology result in the conventional routing protocols for wired networks are not suitable for such a wireless network environment. Currently, most ad-hoc routing protocols are addressed to find the shortest path or the “best” path. From the viewpoint of network applications, the communication behavior among nodes is similar to traditional wired networks, such as HTTP, email, FTP, and so on. There are a lot of clients connecting to servers. The server participates in most connections within a network environment. In this research, we propose a new routing scheme, based on network applications of ad-hoc networks. This routing scheme establishes and maintains a breadth first tree rooted with a node which has the maximum connections. For client/server applications, most connections are associated with servers. This property is useful for ad-hoc routing to reduce the overhead of routing updates especially when the servers are hot servers. The nodes are assigned different spreading code based on the level of the tree to improve packet throughput and to decrease the delay of transmission. Under a certain application, this routing scheme will maintain the shortest routing paths for most connections and decrease the transmission delay. The simulation results show that this routing scheme has better performance when most connections are associated with a specific node.
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