| Summary: | 碩士 === 國立臺灣科技大學 === 管理技術研究所 === 86 ===
The mobile host (MH) technology and wireless networking hardware have become more and more advanced. For example, Wireless LANs are making it possible to support universal network connectivity for mobile computers. In the traditional BS-oriented wireless network, it has the characteristics of reliability and higher performance. However, the ad hoc wireless network topology is more desirable because of its low-cost, plug-and-play convenience, flexbility, and minimal human interaction requirements. Its usage of handwidth and battery power is more efficient. But the route and communication connectivity is fairly "weak". Any migration by Mobile hosts participating in one or more routes will make the route invalid. Therefore, after the routes have been built, we have to maintain it. It takes much cost in communicating with each other. Thus, as hoc wireless network is only suitable for small erea application.
In this thesis, we propose an eclectic and hybrid method to get the advantages and avoid the problems of ad hoc wireless network. The IEEE802.11HIPERLAN and WATM LAN have proposed similar methods. The IEEE802.11 and HIPERLAN have the common feature that the MH must use a fixed transmission mode, either BS-oriented or non-infrastructure network, once the connection is established. WATMLAN is limited to 1-hop-direct-transmission within the BS-oriented network. In order to have more flexibility, reliability, and high performance, we limit the number of hops in direct transmission in a BS-oriented network. The simulation results show that the 2-hop-direct-transmission has a lower non-complete probability. If the communicators were always within a 2-hop-direct-transmission area, we could improve the rate of complete communication about 20%. We slso propose a method to overcome the problem of one BS failure.
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