Analysis and implementation of prediction models for the design of fixed terrestrial point-to-point systems
In this study, propagation link analysis and implementation of prediction models for the design of fixed terrestrial point-to-point systems are aimed. Different propagation models in the literature are examined as case studies and comparisons are made. Rec. ITU-R P.530 Model is analyzed in detail. The worst month link availability is investigated for terrestrial microwave LOS/NLOS radio links operating in NATO Band 3+ (1350-2690 MHz) and NATO Band 4 (4400- 5000 MHz) frequency bands. The calculation of Bullington model of diffraction loss is extended for LOS path case and determination of reflection points on the terrain profile is improved. Several terrestrial microwave LOS/NLOS radio links are analyzed using the propagation parameters such as TX (transmitter) and RX (receiver) station coordinates, path length, frequency, antenna heights above ground level, antenna gains, polarization, radio refractivity gradient, time percentage, target SNR (Signal to Noise Ratio), bandwidth, digital terrain elevation and climate data. The calculation of the received power with the effect of the ground reflection is developed to calculate the fade margin in the defined microwave LOS/NLOS radio links. Received power is calculated by taking into consideration the attenuation due to rain and atmospheric gases, diffraction loss and the effect of multipath fading due to reflection. The validity of the implementation of link analysis is justified by comparison with the commercial ATDI ICS telecom software and the measurement data existing in the literature over sample microwave LOS/NLOS radio links.