Experimental Dynamical Evolution of the Brillouin Precursor for Broadband Wire- Less Communication through Vegetation

In this paper, we report experimental results on detecting and analyzing the Brillouin precursor through vegetation at frequencies from 500 MHz to 3GHz. An experimental method to collect data is reported. The outcomes in terms of energy and time-spreading are presented using modulated rectangular and Gaussian pulses, as well as a sequence of rectangular pulses. Using field-collected data, this study shows the estimated dynamical evolution of the Brillouin precursor fields for wideband wireless systems, such as those represented by IEEE 802.16. The advantages of Brillouin precursors in terms of power spectrum density and bit energy are discussed. Complex relative permittivity is extracted from the experimental data and is used in theoretical formulation to analyze dispersive propagation for any kind of input waveform. Finally, a near-optimal pulse is proposed to achieve maximum propagation distance and/or signal-to-noise ratio for the transmission of bit stream sequences through vegetation.