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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Medhurst, itur attenuation of centimeter waves: Download free trial mlinkplanner is allinone software for microwave point to point link planning. Other methods characterize the statistical rain profile simply by a reduction coefficient, which may be derived from the spatial correlation function of rainfall, from measurements using rapid response rain gauges spaced along a line  or from a semi-empirical law. The main difference in the various methods developed for predicting rain attenuation statistics from rainfall rate measurements is in the models used to describe the time-space structure of rainfall rate.
The basic assumption in the method is that an equivalent cell of uniform rainfall ktu-r and length d 0randomly positioned in the great circle plane, can represent the effect of the non-uniform rainfall along the propagation path.
An alternative, semi-empirical method for the prediction of rain attenuation in terrestrial links was recently proposed , which itur the problems observed in the current ITU-R method.
Itu r p 530 13 pdf file
Lin, “A method for calculating rain attenuation distributions ituu-r microwave paths”, Bell Syst. The presence of hydrometeors, particularly rain, in the propagation path causes scattering and absorption of the propagating wave.
Flat fading modeling in fixed microwave radio links based. Rain attenuation effective path length”, 17 May This empirical model introduces a more precise model than the traditional models.
Acquisition, presentation and analysis of data in studies of tropospheric propagation, 10 The results can be summarized as follows. The raindrops behave as dissipative dielectric media to the incident wave.
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From 12 to 13, there is a radical change in the expression of the geoclimatic K factor and the worst month probability of unavailability. Propagation data and prediction methods required for the. An improved prediction method of rain attenuation for terrestrial light-of-sight path”, 19 September The validation of each new revision is confronted to measurements data collected over the world and available in SG3 database.
These observations indicate that both parameters have an opposite in? For the equivalent cell diameter d 0it was found that a power-law could provide better results than the exponential law used in the current ITU-R method.
The expression obtained is given in 6. Infrared Milli Terahz Waves, vol. Unavailability as function of dN1 P. Weather radar observations show small areas of higher rain rate imbedded in larger regions of lighter rain , .
Unified method for the prediction of rain attenuation in satellite and terrestrial links
The combination of these two effects causes attenuation, which depends the drops conductivity and shape. Locations and main parameters of links. Unified method for the prediction of rain attenuation in satellite and terrestrial links. The recommendation deals only with effects related to the wanted signal.
Assuming that this equivalent rain cell may intercept iut-r link at any position with equal probability, the expression for an effective path length is calculated. Modified prediction method for terrestrial links 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 ith-rwhich is the basis of the model, and uses the full rainfall rate distribution at the links region as input for the prediction of the cumulative distribution of rain attenuation.
Table II and Figs. Rain attenuation statistics over a terrestrial link at Such observations are typical of all occurrences of rain in all climate regions. Iu-r radio signature is useful to quantify the impact of selective fading in broadband systems.
For the slant path case, the data used to test the prediction methods includes concurrent measurements of rainfall rate and rain attenuation in received satellite beacon signals, also available in the ITU-R databank , l.530-13 a total of year-stations from 68 sites in 24 countries. Computation in accordance with the recommendations itu r sm.
However, applying the diversity techniques in particular space diversity e? Section 3 presents p.530–13 studies carried out using our prediction tool, Microwave link simulator, to determine the critical parameters a? The horizontal path reduction factor previously obtained from terrestrial measurements is kept, what ensures consistence between the slant path and terrestrial links cases.
The numerical coefficients in the method’s expressions were derived by multiple non-linear regressions using the experimental data currently available in the ITU-R data banks.
Climatic conditions are also taken into account using local rain database. Theoretical Prediction curve is an upper bound which is validated during the link measurement duration 2 years.
The new method proposed for the prediction of rain attenuation in terrestrial and slant path is.