CHAPTER 3 – Brief Guide to ITU-R P-Series propagation effects and methods 9 3.1 Introduction 9 3.2 Propagation terminology 9 3.3 Guide to RF propagation prediction methods of ITU-R P-Series Recommendations useful for interference analysis 10 3.4 ITU-R P-Series specific RF propagation phenomena 15 3.4.1 ITU-R P-Series specific propagation effects 15 3.5 ITU-R P-Series RF propagation path requirements 19 Chapter 4 – Radiowave propagation phenomena 25 4.1 Introduction 25 4.2 Statistical nature of radio propagation 25 4.3 Interference protection criteria 30 Chapter 5 – Application of ITU-R P-Series propagation models and methods for sharing and interference assessments 33 5.1 Introduction 33
TABLE 3.31 Radiowave propagation prediction methods from selected ITU-R P-Series Recommendations (modified version of Table in Rec. ITU-R P.1144-6) Method Application Type Output Frequency Distance % time % location Terminal height Principle input data Rec. ITU-R P.452 Services employing stations on the surface of the Earth; interference Point-to-point Path loss 100 MHz to 50 GHz Not specified but up to and beyond the radio horizon 0.001 to 50 Average year and worst month Not applicable No limits specified, within the surface layer of the atmosphere. (Not suitable for aeronautical applications) Path profile data Frequency Percentage time Tx antenna height Rx antenna height Latitude and longitude of Tx Latitude and longitude of Rx Meteorological data Rec. ITU-R P.528 Evaluation of basic transmission losses likely to be encountered in the aeronautical services Point-to-area Path loss 125 MHz to 15.5 GHz 0 to 1800 km (for aeronautical applications, 0 km horizontal distance does not mean 0 km path length) 1 to 95 Not applicable H1: 1.5 m to 20 km H2: 1 to 20 km Distance Tx height Frequency Rx height Percentage time Rec. ITU-R P.533 Method for the prediction of the performance characteristics for the prediction of skywave propagation Point-to-point Basic MUF Sky-wave field strength Available receiver power Signal to noise ratio LUF Circuit reliability 2 − 30 MHz Up to 40 000 km All percentages Not applicable Not applicable Latitude and longitude of Tx Latitude and longitude of Rx Sunspot number Time(s) of day Frequency Tx power Tx antenna type Rx antenna type Method Application Type Output Frequency Distance % time % location Terminal height Principle Input data
Rec. ITU-R P.619 Evaluation of interference between stations in space and those on the surface of Earth Point-to-point Interference power level 100 MHz to 30 GHz Not specified Not specified Not applicable No limits specified Path profile data Frequency Percentage time Tx antenna height Rx antenna height Latitude and longitude of Tx Latitude and longitude of Rx Meteorological data Rec. ITU-R P.620 Earth station frequency coordination Coordination distance Distance of the required propagation loss is achieved 100 MHz to 105 GHz Up to 1 200 km 0.001 to 50 Not applicable No limits specified within the surface area of the atmosphere (not suitable for aeronautical applications) Minimum basic transmission loss Frequency Percentage of time Earthstation elevation angle Principle antenna beam 3 dB beamwidth Rec. ITU-R P.1546 Terrestrial services Tropospheric radio circuits over land paths, sea paths, mixed land/sea paths Pointtoarea Field strength 30 to 3 000 MHz 1 to 1 000 km 1 to 50 1 to 99 Tx/base: effective height from less than 0 m to 3 000 m Rx/mobile:> 1 m Terrain heights and ground cover (optional) Path classification Distance Tx antenna height Frequency Percentage time Rx antenna height Terrain clearance angle Percentage locations Refractivity gradient Rec. ITU-R P.1812 Terrestrial services Point-to-point Pointtoarea Field strength 30 MHz to 3 GHz Not specified but up and beyond the radio horizon 1 to 50 1 to 99 No limits specified, within the surface layer of the atmosphere (not suitable for aeronautical applications) Path profile data Frequency Percentage time Tx antenna height Rx antenna height Latitude and longitude of Tx Latitude and longitude of Rx Meteorological data
TABLE 3.4-1 Propagation effects in different frequency bands Frequency band Atmospheric influence Terrestrial influence Applications Comments ELF < 3 kHz Waveguide and cavity propagation with ionosphere as upper boundary Earth forms lower boundary of waveguide, waves propagate deep into earth or sea Longrange communication with submarines, underground remote sensing, etc. Very antennas, very low data rate VLF 330 kHz Waveguide propagation with Dregion as boundary Earth forms lower boundary Worldwide telegraphic services with ships, fixed longrange services, navigational aids, time standards Very large antennas, low data rate LF kHz below D region up to 100 kHz, sky waves distinct from ground waves above 100 kHz Ground waves follow Earth Longrange communication with ships, medium distance navigation systems Large antennas, difficult to make it directional MF 3003 000 kHz Sky waves for longer distances and higher frequencies Surface waves for shorter distances and lower frequencies, ground reflections Broadcasting, navigational aids, other mobile and fixed services Large but efficient antennas, service area about 100 km during day, much longer distances possible at night HF 330 MHz Ionospheric beyond skip distance (6-30 MHz) Surface waves only at short distance (3-6 MHz), reflection, scatter Fixed point-to-point, land, maritime and aeronautical mobile, long distance broadcasting Curtain arrays, vertical whips, log periodic arrays VHF 30300 MHz Tropospheric waves sporadic E cause interference Terrestrial LOS and BLOS with diffraction, multipath effects due to reflection Broadcasting, land, aeronautical and maritime mobile, cordless telephones, radionavigation Yagi, and helixes used UHF 300-3 000 MHz Refraction, reflection at lower and ducting at higher frequencies, troposcatter above about 500 MHz Terrestrial and Earthspace LOS and slightly BLOS, screening by hills and buildings TV broadcasting, radars, fixed point-to-point, mobile, MSS, BSS, FSS, cellular radio, cordless telephones Both wideband and high gain antennas used
TABLE 3.4-1 (end) Frequency band Atmospheric influence Terrestrial influence Applications Comments SHF 3-30 GHz Refraction and ducting, attenuation due to rain etc., scintillation, ducting may interference, multipath cause fading, absorption by rain, snow, fog, cloud and gases Terrestrial and Earthspace LOS, diffraction and screening due to buildings, scatter and reflection from buildings, terrain, trees and sea Fixed terrestrial and satellite services, mobile, future MSS, radar remote sensing High gain parabolic dishes and horns MILLIMETRIC EHF 30-300 GHz Refractive index gradient, rain etc. cause attenuation and scatter, absorption by water vapour and oxygen, scintillation Terrestrial short distance LOS, screening by buildings and foliage Shortrange and mobile communication systems, satellite applications, remote sensing, radars Small parabolic dishes SUBMILLIMETR 300-3 000 GHz Localized refractive index gradient, rain etc. cause severe attenuation, absorption by gases, scintillation Very short range LOS, screening by trees Shortrange communications, remote sensing Mirror or lens antennas, equipment lacking INFRARED AND OPTICAL 3-430 THz and 430-860 THz Localized refractive gradient, rain etc. cause very severe attenuation, absorption by gases, scintillation LOS, screening by small objects Shortrange and indoor for farinfrared, alarms, smoke detectors, remote control and spectrometry for nearinfrared, optical LOS links Mirrors and lenses for antennas
As a prelude to subsequent discussion, it will be useful to introduce the concept of the deviation. We want to compute the quantiles of transmission loss at distance ,. The distributions involved are nearly normal, so it simplifies the calculation to express the fractions in terms of standard normal deviates. The complementary normal distribution is given by: (4.1) and the standard normal deviate, z, is obtained from the inverse function: (4.2) If the field strength, E (dB), is a normally distributed random variable with mean (also equal to its median) and standard deviation , then its quantiles are given by: . (4.3) Note the convention that the positive direction of deviation corresponds to an increase in field strength, hence a decrease in loss. To obtain the twofold quantile of basic transmission loss,, we write: (4.4) the overall median value, , and the deviations, YL and YT, may be written: (4.5a) for (4.5b) and where the “pseudostandard deviation” of the time variability, , is a function of the distance, x. A method for computing the “pseudostandard deviation” of the time variability, , is given below, since it is not explicitly given in the Recommendations. For certain interference and/or sharing studies involving mobile services, it may be necessary to calculate the combined time and location variability. In those cases, the root sum square approximation may be used to the combined variability. To obtain the “pseudostandard deviation” of the time variability,, use the 10% time and 50% time quantiles of the field strengths [dB]: (4.6a) or, in terms of the corresponding quantiles of basic transmission losses in dB,
Space research service deep-space: space-to-Earth I ≤ −222 dB(W/Hz) in bands near 2 GHz I ≤ −221 dB(W/Hz) in bands near 8 GHz I ≤ −220 dB(W/Hz) in bands near 13 GHz I ≤ −217 dB(W/Hz) in near 32 GHz ITU-R SA.1157 research service deep-space: Earth-to-space I ≤ −193 dB(W/20 Hz) in bands near 2 GHz I ≤ −190 dB(W/20 Hz) in bands near 7 GHz I ≤ −186 dB(W/20 Hz) in near 17 GHz I ≤ −183 dB(W/20 Hz) in bands near 34 GHz ITU-R SA.1157 Space research service 37 and 40 GHz bands links) I/N≤−6 dB ITU-R SA.1396 Space research service 37 and 40 GHz bands (Earth-to-space links) I/N≤ 0 dB ITU-R SA.1396 Data satellite outside S-Band I ≤−178 dBW ITU-R SA.1155 Data relay satellite in S-Band I ≤−181 dBW ITU-R SA.1274 operation systems space-to-Earth links I ≤−184 dBW ITU-R SA.363 Space operation systems Earth-to-space links C/I ≥ 20 dB