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COEXISTENCE MECHANISMS FOR LEGACY AND NEXT GENERATION
WIRELESS NETWORKS PROTOCOLS
by
Alex Chia-Chun Hsu
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Ful¯llment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ELECTRICAL ENGINEERING)
May 2008
Copyright 2008 Alex Chia-Chun Hsu
Object Description
| Title | Coexistence mechanisms for legacy and next generation wireless networks protocols |
| Author | Hsu, Alex Chia-Chun |
| Author email | protoalex@hotmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2007-11-13 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-01-29 |
| Advisor (committee chair) | Kuo, C. C. Jay |
| Advisor (committee member) |
Neely, Michael J. Govindan, Ramesh |
| Abstract | Effective usage of unlicensed bands (UB) has received a lot of attention due to its potential in ubiquitous computing and networking. One key issue in effective UB usage is the coexistence among devices of homogeneous or heterogeneous systems, e.g. wireless local area networks (WLAN) and wireless personal area networks (WPAN). To resolve the coexistence problem, we need to understand the interaction between concurrent transmissions in overlapping frequency bands. Although some basic interference resolving process is mentioned in the standards, further performance improvement can be achieved by careful system analysis and parameter selection. In this research, we analyze the coexistence problem that these systems face and devise coexistence mechanisms to enhance performance.; We develop a suitable analytical model that can accurately model the interference phenomena between WLANs and WPANs. Then, we propose non-collaborative solutions for WLAN and WPAN, respectively. For WLAN, we propose a dynamic fragmentation (DF) mechanism to optimize the packet length such that Wi-Fi devices have better chance to avoid the interference caused by Bluetooth piconets. Both theoretical analysis and simulation results confirm that DF can significantly improve the performance of Wi-Fi in terms of throughput and transmission delay.; For WPAN, we propose an adaptive hopset frequency hopping (AHFH) mechanism to avoid the interference from coexisting WLAN as well as the self-interference from collocating Bluetooth piconets. With AHFH, a piconet adjusts its hopset to minimize the interference adaptively. Results show that AHFH improves performance and adaptability to the dynamic changes in the environment.; Stale and inefficient current spectrum regulation and the crowded ISM band makes flexible "cognitive radio (CR)" the logical next step. Along this research direction, we propose a statistic channel allocation MAC (SCA-MAC) and a dynamic spectrum access MAC (DSA-MAC). Both protocols can exploit the "spectrum hole" on unlicensed bands and minimize their interference on incumbent users and collision with other CR nodes. SCA-MAC avoids interference with primary services through statistics, and improves spectrum efficiency. DSA-MAC further investigates strategies of the operation range assignment. Three strategies, namely, non-sharing (NS), partial sharing (PS) and full sharing (FS), were discussed and compared under various scenarios. It is shown that FS gives the best throughput. |
| Keyword | MAC protocol; Wi-Fi 802.11; Bluetooth 802.15 |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m998 |
| Contributing entity | University of Southern California |
| Rights | Hsu, Alex Chia-Chun |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Hsu-20080129 |
| Archival file | uscthesesreloadpub_Volume26/etd-Hsu-20080129.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | COEXISTENCE MECHANISMS FOR LEGACY AND NEXT GENERATION WIRELESS NETWORKS PROTOCOLS by Alex Chia-Chun Hsu A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Ful¯llment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (ELECTRICAL ENGINEERING) May 2008 Copyright 2008 Alex Chia-Chun Hsu |
