| Summary: | 碩士 === 真理大學 === 數理科學研究所 === 89 === Ad-hoc wireless networks consist of mobile hosts in a network bereft of base stations and characterized by a highly dynamic network topology. The network topology changes frequently due to host migration, signal interference and power outages. This makes routing maintenance poses challenges in ad-hoc routing protocol design. In this thesis, two research topics will be presented. Firstly, we presents an active routing maintenance protocol that maintains an existed route by preventing route-disconnection. By keeping track of the information of signal strength and stability of individual hosts, an active node that causes the route to a weak connection will actively issue a route reestablishing process in which active node selects one of its neighbors as the candidate to replace it as a router.
The second topic of this research is short-message service for Ad-Hoc Networks. In ad-hoc networks, there exist unpredictable obstacles, such as mountain, lakes, buildings, or a region without any host located, which impedes or block the message relay. In the Second part of thesis, we propose geocasting protocols for sending short message from a source host to single or multiple geocasting regions in ad-hoc networks. The proposed protocols keep message away from the unpredictable obstacles and create a small flooding region. Experimental results show that a source host can send a short message to all hosts located in single or multiple geographical areas with high successful rate and low flooding overhead.
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