Event
M.S. Thesis Defense: Sangjin Han
Wednesday, April 23, 2014
10:00 a.m.
2328 AVW
Maria Hoo
301 405 3681
mch@umd.edu
ANNOUNCEMENT: M.S. Thesis Defense
Name: Sangjin Han
Committee
Professor Ashok Agrawala (CS): Advisor/Chair
Professor Charles Silio (ECE)
Professor Bobby Bhattacharjee (CS)
Date/Time: April 23, 2014 at 10:00 AM to 12:00 PM
Place: AVW 2328 (Seminar reservation follows at the end of this email.)
Title and abstract:
Title of thesis: CLOCK SYNCHRONIZATION AND TARGET LOCATION DETERMINATION IN WIRELESS NETWORKS
In a distributed system most nodes maintain a local oscillator to derive time information for synchronization with other nodes. A number of clock synchronization techniques have been presented in the literature (e.g. NTP, PTP) which rely on the exchange of messages among nodes to share timing information and to adjust the o?set or skew of the clocks. We present an approach which does not require any adjustments to the local clocks, but relies on achieving synchronization through clock mapping functions which map the time at one node to the time at another node. We further show how closed paths in a graph of nodes can be used to estimate the synchronization tolerance. Through experimental results using piecewise linear functions, we demonstrate the feasibility of this approach and show how clock synchronization of better than 100 ps can be achieved in Wi-Fi environments.
Using the techniques and relying on the hardware of SMiLE3 board, we also demonstrate the ability to measure distance with accuracy of a few inches and thereby the localization to accuracy better than one foot. Results of experiments conducted for localization are also presented.
