Analysis of Brillouin Precursor Propagation Through Foliage for Digital Sequences of Pulses

Experimental Dynamical Evolution of the Brillouin Precursor for Broadband Wireless Communication Through Vegetation

“…10, the total average propagated field E T (t, z) follows an algebraically decaying peak amplitude, governed by 0.48 · ∆z −7/9 and 0.44 · ∆z −7/8 , for V V and HH polarizations, respectively. This may be compared with the theoretical simulation in [10] using the Maetzler dielectric model indicating the peak amplitude decay governed by 0.5 · ∆z −2/3 . It may be reasonable to assume that this difference is mainly due to the effects of the polidispersive nature of the vegetation medium that cannot be modeled as a homogeneous space.…”

“…The estimated dielectric permittivity can then be used to predict the behavior of any input signal. In [10], we have introduced a formulation to predict the precursor formation and its evolution within a given dispersive medium [15]. This formulation is based on the fact that a bandlimited sine-modulated pulse x(t) can be re-constructed in the timedomain considering only a limited set of 2M + 1 orthogonal frequency components around its carrier frequency, f 0 , as in (4):…”

“…10 that the Brillouin precursor formed in the leading and trailing edges of each pulse produces a deformation of the sequence if a bit phase change transition occurs. The phases of the two adjacent bits will determine the peak level cancellation or reinforcement of the two adjacent precursors: cancelled if bit phase continuity takes place and added if bit phase transition occurs [10].…”

“…Therefore, typical theoretical vegetation models, such as the Maetzler model [10,19], assuming a continuous vegetation may not be suitable for the case Figure 10.…”

“…These data were also used to calculate the complex relative dielectric permittivity ε r (ω) of the underlying dispersive material [8,9]. The estimated permittivityε r (ω) together with the theoretical formulation in [10] was used to predict the dynamical evolution of any kind of input pulse traveling through the material. Both theoretical and experimental methods have been used to detect and analyze the Brillouin precursor corresponding to sine-modulated rectangular and Gaussian pulses, as well as for a modulated sequence of rectangular pulses.…”