Reliable strategies for wireless mobile environments /
The research presented in this dissertation deals with the following performance issues in wireless mobile networks: fault diagnosis, fault-tolerant location management and robust handoff. Fault diagnosis is implemented at the interface between the wired and wireless networks, i.e. at each base sta...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=727726061&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The research presented in this dissertation deals with the following performance issues in wireless mobile networks: fault diagnosis, fault-tolerant location management and robust handoff. Fault diagnosis is implemented at the interface between the wired and wireless networks, i.e. at each base station. The geographical region of a wireless system can be hierarchically divided into sub-regions (urban center, urban, and suburban) depending on features such as density of traffic and population of mobile hosts. Performance requirements such as volume of signaling and low diagnostic latency are more severe in the urban center. By applying existing diagnosis approaches a degradation in the usual performance metrics likely will occur. In this dissertation, we propose an adaptive diagnosis technique for a wireless mobile system in the urban center to achieve a low diagnosis latency and small amount of signaling volume. The analytical model and simulation are built to analyze the performance of each test schedule and scenario in terms of diagnosis latency and volume of signaling. In order to prevent the failure of call delivery, fault tolerance is incorporated using a forwarding pointer technique with no need for paging using a location counter. The proposed strategy guarantees call delivery to a callee mobile host without paging and waiting. Also, as the cost for paging is higher than checking the location counter, then the proposed strategy has a significantly reduced total cost for location management in the presence of at least one faulty visitor location register comparing with the IS-41 Standard and a simple forwarding pointer strategy. Most handoff strategies have focused on forwarding or forwarding and re-routing techniques using so-called hysteresis h to prevent the ping-pong effect. However, it has resulted in the delay or critical loss (unacceptable level of quality-of-service) on the active connection of a mobile host. In order to overcome this trade-off problem and to achieve robust handoff, the single point-to-multipoint technique using early warning message with the hysteresis is applied in a Multi-Leveled Hierarchical Personal Communication Network (MLHPCN) environment. An analytical model is built to analyze the performance in terms of reliability, signaling and buffer overheads of the proposed strategy and number of handoffs in the MLHPCN environment. |
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| Item Description: | Vita. "Major Subject: Computer Science". |
| Physical Description: | xii, 146 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 134-142). |