CSU HAYWARD
DEPARTMENT OF MATHEMATICS AND
COMPUTER SCIENCE
THESIS PRESENTATION
Wednesday, October 22, 2002; 2:40-3:40pm Sc N215
Speaker: Vasantha Jayakumar
In recent years, there has been rapid growth in the field of wireless communication that has led to a large number of mobile users with increasing demands and expectations. Wireless communication exhibits a whole new set of challenges when compared to wired communication. In the case of wireless communication and microcellular data networks, the bandwidth is shared amongst all users within a specific network coverage area. Available bandwidth for a particular mobile user will vary dynamically based on the mobility of the user and the movements of other hosts into and out of the coverage area. Some of the other problems are frequent and lengthy disconnections, high error rates for packets and packet loss. Hence, the need arises for tools to measure and analyze network characteristics to provide knowledge about the wireless environment thus enabling the mobile user to adapt to the changes in the environment.
In this study, we discuss several challenges of wireless networks and the design and implementation of a wireless link quality mapper (LQM) which tracks link quality measurements with respect to the location of the mobile user. A GPS device is connected to the mobile unit to provide the location information. The LQM is designed to perform measurements in three different modes namely passive, active and assisted based on the level of feedback required by the user, the availability of power etc. Several network statistics are recorded in these modes of measurement. The history of the measured network statistics along with the time and location of measurement are stored in a database. Comparison of these statistics over time or location provides valuable information to the mobile user. The dynamically varying bandwidth and the obstacles in the mobile users environment may cause drastic changes in the link quality. Hence, using the history of information collected, the user may determine if the disconnection or poor link quality at a location is temporary or persistent. The LQM is implemented using the Java programming language and the measurements are displayed in several graphical formats such as histograms and map representations that would serve as value adds to the user. The design and implementation of a network emulator used for testing the LQM is also discussed.