Recent widespread use of computer and wireless communication technologies has increased the demand of data services via wireless channels. However, providing high data rate in wireless system is expensive due to many technical and physical limitations. Unlike voice service, data service can tolerate delays and allow burst transfer of information, thus, an alternative approach had to be formulated. This approach is known as ???Infostation.??? Infostation is an inexpensive, high speed wireless disseminator that features discontinuous coverage and high radio transmission rate by using many short-distance high bandwidth local wireless stations in a large terrain. As opposed to ubiquitous networks, each infostation provides independent wireless connectivity at relative shorter distance compare to traditional cellular network. However, due to the discontinuous nature of infostation network, there is no data service available between stations, and the clients become completely disconnected from the outside world. During, the disconnected period, the clients have to access information locally. Thus, the need for a good wireless network caching scheme has arisen. In this dissertation, we explore the use of the infostation model for disseminating and caching of data. Our initial approach focuses on large datasets that exhibit hierarchical structure. In order to facilitate information delivery, we exploit the hierarchical nature of the file structure, then propose generic content scheduling and cache management strategies for infostations. We examine the performance of our proposed strategies with the network simulator Qualnet. Our simulation results demonstrate the improvement in increasing the rate of successful data access, thus alleviating excessive waiting overheads during disconnected periods. Moreover, our technique allows infostations to be combined with traditional cellular networks and avoid accessing data via scarce and expensive wireless channel for the purpose of cost reduction.
| Identifer | oai:union.ndltd.org:ADTP/257168 |
| Date | January 2006 |
| Creators | Wang, Jerry Chun-Ping, Computer Science & Engineering, Faculty of Engineering, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Computer Science & Engineering |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Jerry Chun-Ping Wang, http://unsworks.unsw.edu.au/copyright |
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