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Title:Producing Artificial Frequently Shifts Using Piezoelectric Actuators
Author(s):El Bassiouny, Omar A.
Contributor(s):Bernhard, J.T.; Veeravalli, V.V.
piezoelectric actuators
frequency shift
vibrating reflectors
wireless communication
Abstract:The Doppler shift is a natural phenomenon that is an effect of the relative movement between a transmitter and a receiver. By measuring it one can extract suffi cient information to discern the speed and direction of this relative motion. Consequently, the ability to manipulate the Doppler shift allows for direct control over the propagation of such information. The purpose of this research is to develop a method to produce prescribed frequency shifts by introducing vibrating reflectors to a wireless environment. A vibrating reflector implemented using piezoelectric actuators, adds extra time-varying delay to an incident signal which translates into a frequency shift. Piezoelectric actuators are devices that expand and contract in proportion to an applied voltage. Advances in the development of piezoelectric materials have enabled them to produce high frequency movement, which is necessary to create realistic frequency shifts. By adjusting the speed of the actuators, one can obtain different frequency shifts depending on the frequency of the incident signal. This method to produce artificial frequency shifts can be used to compensate for the reduced frequency shifts experienced by mobiles moving at limited speeds in wireless testbeds implemented in confined spaces. The Wireless Wind Tunnel (WWT) is a testbed for implementing down-scaled versions of wireless networks inside an anechoic chamber at the University of Illinois at Urbana-Champaign. It allows for accurate, controlled and repeatable evaluation of wireless protocols. Vibrating reflectors can generate large enough shifts to enable the testing of realistic scenarios.
Issue Date:2008-12
Publication Status:unpublished
Peer Reviewed:not peer reviewed
Date Available in IDEALS:2014-03-11

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