ITU-R P.530-13 PDF
P Draft revision of Recommendation ITU-R P – Propagation data and prediction methods required for the design of terrestrial. ITU-R WP3M Contribution Title: On the development of Recommendation ITU-R P – Prediction of autage intensity for digital line-of-sight systems. ITU-R P 4. 1. 0. – B. D. Ad. – 1. 0. 1. – – GHz 2. % ke.. (dB) h/F1. B.: D.: GHz 6,5. 4/3 = ke. Ad.: (2) h.
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Da Silva Mello, L. User Username Password Remember me. Pdf the effect of terrain roughness in the microwave line.
Propagation data and prediction methods required for the. Effective path length for slant paths The model for the effective path length can be extended for the slant path case by considering the rain height.
Other methods characterize the statistical rain profile simply by p5.30-13 reduction coefficient, which may be derived from the spatial correlation function of rainfall, from measurements using rapid response rain gauges spaced along iu-r line  or from p.503-13 semi-empirical law. Spartial temporal structure of rain, 2nd Edition, Propagation of Radio Waves.
The methods for the prediction of rain attenuation in slant path links and terrestrial links currently recommended by the ITU-R are based on simplified models for the rain field affecting the propagation path. The dependence of the effective rainfall rate with the point rainfall rate, the slant path length the elevation iut-r and the rain height found in the experimental data is shown in Figs.
The expression obtained is given in 6. Another important limitation is that, when tested against the experimental data now available, the terrestrial prediction method shows significant underestimation of the measured attenuations.
The examination of version 13 shows that there are two major modi?
Unified method for the prediction of rain attenuation in satellite and terrestrial links
The numerical coefficients in the method were derived by multiple non-linear regressions using the experimental data of rain attenuation in terrestrial links currently available in the ITU-R data banks. In this paper, a semi-empirical method for the prediction of rain attenuation in slant paths and terrestrial links is proposed.
The cumulative distribution of rain attenuation is obtained from the distribution of rainfall rate in the links region by. A correction factor r p was ituu-r not only for 0. A modified method has been proposed  that addresses some of the problems found in the current ITU-R method but retains the general expression for d effwhich is the o.530-13 of the model, and uses the full rainfall rate distribution at the links region as input for the prediction of the o.530-13 distribution of rain attenuation.
Propagation data and prediction methods required for the design of terrestrial line-of-sight systems, Transmission analysis of a single hop for microwave link.
Table I shows the average values, standard deviations and the r.
Link Calculation » ALCOMA
Measurement and prediction curves have similar tendency. Consistency between the terrestrial and the slant path itj-r was also achieved, which is not present in any of the methods tested. Some methods derive the statistical profile of rain along p.530-3 path assuming a single cell of suitable shape , or a statistical distribution of sizes for cells of a particular shape , , .
The basic assumption in these methods is that an equivalent cell of uniform rainfall rate can model the non-uniform rainfall along the propagation path. The utu-r for this factor is derived using the experimental data on rain attenuation in slant path links currently available in the ITU-R data bank.
The performance is essentially equivalent to that of the method proposed by China, which presents inconsistencies from the physical point of view. This empirical model introduces a more precise model than the traditional models.
For percentages of time between 0. It is usually found that, to correct the underestimation simply by refitting the method against the larger database of experimental data now available, it would be necessary to allow for effective path lengths longer than the actual path length.
This means that the method will provide the same results for two sites that have the same p530-13 for the rainfall rate exceeded at 0. Even considering that the attenuation dependence with these two variables is weaker, it is expected from a physical point of view and they were included in the method. An alternative, semi-empirical method for the p.5301-3 of rain attenuation in terrestrial links was recently proposed , which addresses the problems observed in the current ITU-R method.
This concept of an effective path length, to take into account the non-uniform profile of rain intensity along a given path in the prediction of the rain attenuation cumulative distribution on radio links, is presently used in attenuation prediction methods such as that in Recommendation ITU-R P.
The new method proposed for the prediction of rain attenuation in terrestrial and slant path is. Matricciani, “Global formulation of the Synthetic Storm Technique to calculate rain attenuation only from rain rate probability distributions”, Antennas and Propagation Symposium, Propagation data and prediction methods required for the design itur- terrestrial line-of-sight systems”, 11 April The test results indicate that, for the terrestrial case, the proposed method provides a large improvement over the method currently recommended by the ITU-R.
These functions have been developed as curve-fittings to power-law coefficients derived from scattering calculations. Also, the slant path and terrestrial prediction methods are not consistent, as different expressions for the horizontal path reduction factor are used in each case.