THE RAINFALL INTENSITY EFFECTS ON 1-13 GHZ ULTRAWIDEBAND PROPAGATION AT TROPICAL AREAS

• Main Author: SURYANA (NIM : 33204015); Tim Pembimbing : Andriyan Bayu Suksmono,PhD; Dr. Ir. Sugihartono; Dr, JOKO
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/16185
• Institution: Institut Teknologi Bandung

The performance of UWB systems predominantly depends on impulse response of the end to end channel between transmitter and receiver. When the effects of outdoor UWB channel distort the received pulse waveforms significantly, the probability of unsuccessful symbol detection will increase. In such cases, the phase nonlinearity and magnitude variability profiles of antenna and channel will responsible for UWB pulse distortions. Taking into account the channel effects, this dissertation also reported the contribution on tropical outdoor channel characterization in UWB 1-13 GHz band by theoretical modelling approach as well as performing the outdoor channel measurements with rain intensity as the most important variable, i.e from 20 mm/h to 200 mm/h. Rain-filled medium channel model is developed by Mie scattering approach of multiple raindrops whose drop size is distributed as Marshall-Palmer distribution with Liebe’s complex permittivity . A numerical computation of UWB pulse distortions has also been evaluated, in terms of amplitude, duration and their associated time delay on several rain intensities. Numerical computation results show that pulse broadening and waveform distortion completely depend on the rain intensity as well as the distance between TX and Rx. These numerical computation results have also been validated with the 1-13 GHz outdoor channel measurements by using rain simulator which was developed in our laboratory. To achieve better understanding of UWB communication performance due to pulse distortion by antenna and tropical outdoor effects, a BER formulation with matched filter and correlator-based receivers are also derived. The BER simulation results show that increasing the rainfall intensity will degrade the UWB performance. At no rain conditions, BER 10-6 will be attained with S/N 5 dB, but when the highest rainfall intensity 200 mm/h, the BER will fall to 10-2 for matched filter and 5.10-2 for correlator receivers. An adaptive nonlinear phase equalizer is also proposed for achieving better BER. The proposed equalizer adopts multiple allpass biquad IIR filters combined with low-order FIR filter for compensating non linearity phase and differential attenuation of magnitude responses due to antenna and channel effects. Simulation results show that UWB system has worked successfully with BER 10-6 during on R0.01 rain intensity or 99.99% availability. In addition, at rainfall rate 120 mm/h, the proposed non-linear phase equalizer can give 9 dB signal improvement better than UWB system without phase compensator.