1、 Recommendation ITU-R P.1546-5(09/2013)Method for point-to-area predictions for terrestrial services in the frequency range 30 MHz to 3 000 MHzP SeriesRadiowave propagationii Rec. ITU-R P.1546-5 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and ec
2、onomical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed
3、by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be
4、used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found.
5、Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiode
6、termination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG
7、Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2013 ITU 2013 All rights reserved. No part of this p
8、ublication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R P.1546-5 1 RECOMMENDATION ITU-R P.1546-5 Method for point-to-area predictions for terrestrial services in the frequency range 30 MHz to 3 000 MHz (2001-2003-2005-2007-2009-2013) Scope This Recommenda
9、tion describes a method for point-to-area radio propagation predictions for terrestrial services in the frequency range 30 MHz to 3 000 MHz. It is intended for use on tropospheric radio circuits over land paths, sea paths and/or mixed land-sea paths up to 1 000 km length for effective transmitting a
10、ntenna heights less than 3 000 m. The method is based on interpolation/extrapolation from empirically derived field-strength curves as functions of distance, antenna height, frequency and percentage time. The calculation procedure also includes corrections to the results obtained from this interpola
11、tion/extrapolation to account for terrain clearance and terminal clutter obstructions. The ITU Radiocommunication Assembly, considering a) that there is a need to give guidance to engineers in the planning of terrestrial radiocommunication services in the VHF and UHF bands; b) that, for stations wor
12、king in the same or adjacent frequency channels, the determination of the minimum geographical distance of separation required to avoid unacceptable interference due to long-distance tropospheric propagation is a matter of great importance; c) that the curves that appear in Annexes 2, 3 and 4 are ba
13、sed on the statistical analysis of experimental data, noting a) that Recommendation ITU-R P.528 provides guidance on the prediction of point-to-area path loss for the aeronautical mobile service for the frequency range 125 MHz to 15.5 GHz and the distance range up to 1 800 km; b) that Recommendation
14、 ITU-R P.452 provides guidance on the detailed evaluation of microwave interference between stations on the surface of the Earth at frequencies above about 0.1 GHz; c) that Recommendation ITU-R P.617 provides guidance on the prediction of point-to-point (P-P) path loss for trans-horizon radio-relay
15、systems for the frequency range above 30 MHz and for the distance range 100 to 1 000 km; d) that Recommendation ITU-R P.1411 provides guidance on prediction for short-range (up to 1 km) outdoor services; e) that Recommendation ITU-R P.530 provides guidance on the prediction of P-P path loss for terr
16、estrial line-of-sight systems; f) that Recommendation ITU-R P.2001 provides a wide-range terrestrial propagation model for the frequency range 30 MHz to 50 GHz including both fading and enhancement statistics, 2 Rec. ITU-R P.1546-5 recommends that the procedures given in Annexes 1 to 8 should be use
17、d for point-to-area prediction of field strength for the broadcasting, land mobile, maritime mobile and certain fixed services (e.g. those employing point-to-multipoint (P-MP) systems) in the frequency range 30 MHz to 3 000 MHz and for distances up to 1 000 km. NOTE Long range propagation paths may
18、also occur at VHF via the ionosphere. These modes are summarized in Recommendation ITU-R P.844. Annex 1 Introduction 1 The propagation curves The propagation curves in Annexes 2, 3 and 4 represent field-strength values for 1 kW effective radiated power (e.r.p.) at nominal frequencies of 100, 600 and
19、 2 000 MHz, respectively, as a function of various parameters; some curves refer to land paths, others refer to sea paths. Interpolation or extrapolation of the values obtained for these nominal frequency values should be used to obtain field-strength values for any given required frequency using th
20、e method given in Annex 5, 6. The curves are based on measurement data mainly relating to mean climatic conditions in temperate regions containing cold and warm seas, e.g. the North Sea and the Mediterranean Sea. The land-path curves were prepared from data obtained mainly from temperate climates as
21、 encountered in Europe and North America. The sea-path curves were prepared from data obtained mainly from the Mediterranean and the North Sea regions. Extensive studies reveal that propagation conditions in certain areas of super-refractivity bounded by hot seas are substantially different. However
22、, the methods for interpolation and extrapolation between the families of field-strength curves are general. Therefore, if families of curves exist for regions with different climates which experience substantially different prevailing radio propagation conditions, accurate characterization of radio
23、 propagation in these regions may be attained using the methods found in this Recommendation. This Recommendation is not specific to a particular polarization. 2 Maximum field strengths The curves have upper limits on the possible value of field strength which may be obtained under any conditions. T
24、hese limits are defined in Annex 5, 2 and appear as dashed lines on the graphs reproduced in Annexes 2, 3, and 4. Rec. ITU-R P.1546-5 3 3 Computer-based tabulations Although field strengths may be read directly from the curves presented as figures in Annexes 2, 3 and 4 of this Recommendation, it is
25、intended that computer implementations of the method will use tabulated field strengths available from the Radiocommunication Bureau. See that part of the ITU-R website dealing with Radiocommunication Study Group 3. 4 Step-by-step method The detailed step-by-step procedure to be used in the applicat
26、ion of this Recommendation is given in Annex 6. 5 Designation of antennas In this Recommendation, the term “transmitting/base antenna” is used to deal with both the concept of transmitting antenna as used in the broadcasting service and the concept of base station antenna as used in the terrestrial
27、mobile services. Similarly, the term “receiving/mobile antenna” is used to deal with the concept of a receiving antenna as used in the broadcasting service and a mobile antenna as used in the terrestrial mobile services. More information on the designation of the terminals can be found in Annex 5, 1
28、.1. 6 Transmitting/base antenna height The method takes account of the effective height of the transmitting/base antenna, which is the height of the antenna above terrain height averaged between distances of 3 to 15 km in the direction of the receiving/mobile antenna. The transmitting/base antenna h
29、eight, h1, to be used for calculations is obtained using the method given in Annex 5, 3. 7 Transmitting/base antenna heights used for curves The field strength versus distance curves in Annexes 2, 3 and 4, and the associated tabulations, are given for values of h1of 10, 20, 37.5, 75, 150, 300, 600 a
30、nd 1 200 m. For any values of h1in the range 10 m to 3 000 m an interpolation or extrapolation from the appropriate two curves should be used, as described in Annex 5, 4.1. For h1below 10 m, the extrapolation to be applied is given in Annex 5, 4.2. It is possible for the value of h1to be negative, i
31、n which case the method given in Annex 5, 4.3 should be used. 8 Time variability The propagation curves represent the field-strength values exceeded for 50%, 10% and 1% of time. A method for interpolating between these values is given in Annex 5, 7. This Recommendation is not valid for field strengt
32、hs exceeded for percentage times outside the range from 1% to 50%. 9 Mixed-path method In cases where the radio path is over both land and sea the estimate of mixed-path field strength should be made using the method given in Annex 5, 8. 4 Rec. ITU-R P.1546-5 10 Receiving/mobile antenna height For l
33、and paths the curves give field-strength values for a receiving/mobile antenna height above ground, h2(m), equal to either the representative height of ground cover around the receiving/mobile antenna location, or 10 m, whichever is the higher. For sea paths the curves give field-strength values for
34、 h2= 10 m. To allow for values of h2different from the height represented by a curve a correction should be applied according to the environment of the receiving/mobile antenna. The method for calculating this correction is given in Annex 5, 9. 11 Effect of clutter shielding transmitting/base antenn
35、a If the transmitting/base antenna is over or adjacent to land on which there is clutter, the correction given in Annex 5, 10 should be applied, irrespective of the transmitting/base antenna height above ground. 12 Terrain clearance angle correction For land paths, improved accuracy of predicted fie
36、ld strengths can be obtained by taking into account terrain near the receiving/mobile antenna, if available, by means of a terrain clearance angle. When a calculation for a mixed path has been made, this correction should be included if the receiving/mobile antenna is adjacent to a land section of t
37、he path. More information on the terrain clearance angle correction is given in Annex 5, 11. 13 Location variability The propagation curves represent the field-strength values exceeded at 50% of locations within any area of typically 500 m by 500 m. For more information on location variability and t
38、he method for calculating the correction required for percentages of location other than 50%, see Annex 5, 12. 14 Correction based on tropospheric scattering Annex 5, 13 gives a method for taking tropospheric scattering into account to be used if terrain information is available. In principle the cu
39、rves should reflect the effect of any significant troposcatter signals, but it is not certain that sufficient measurements were conducted at the long distances required to capture such effects. The correction in Annex 5, 13 is intended to make it unlikely that a field strength will be seriously unde
40、r-predicted due to the curves not adequately representing tropo-scatter effects. 15 Correction for antenna height difference Annex 5, 14 gives a correction to account for the difference between the two antenna heights above ground. 16 Horizontal distances less than 1 km The field strength curves cov
41、er horizontal distances from 1 km to 1 000 km. Annex 5, 15 describes the method for horizontal distances less than 1 km. Rec. ITU-R P.1546-5 5 17 Equivalent basic transmission loss Annex 5, 17 gives a method for converting from field strength for 1 kW e.r.p. to the equivalent basic transmission loss
42、. 18 Variability of atmospheric refractive index It is known that median field strength and its variability over time varies in different climatic regions. The field strength curves given in Annexes 2, 3 and 4 apply to temperate climates. Annex 7 gives a method of adjusting the curves for different
43、regions of the world based on the vertical atmospheric refractivity gradient data associated with Recommendation ITU-R P.453. 19 Compatibility with the Okumura-Hata method Annex 8 gives the Hata equations for field strength prediction for mobile services in an urban environment, and describes the co
44、nditions under which this Recommendation gives compatible results. Annex 2 Frequency range 30 MHz to 300 MHz 1 The field strength versus distance curves shown in this Annex are for a frequency of 100 MHz. They may be used for frequencies in the range 30 MHz to 300 MHz but the procedure given in Anne
45、x 5, 6 should be used to obtain improved accuracy. The same procedure should be used when the tabulated values of field strength versus distance (see Annex 1, 3) are employed. 2 The curves in Figs 1 to 3 represent field-strength values exceeded at 50% of the locations within any area of approximatel
46、y 500 m by 500 m and for 50%, 10% and 1% of the time for land paths. 3 The field strength distribution as a function of percentage location may be calculated using the information in Annex 5, 12. 4 The curves in Figs 4 to 8 represent field-strength values exceeded at 50% of the locations for 50%, 10
47、% and 1% of the time for sea paths in cold seas and warm seas, for example, those observed in the North Sea and the Mediterranean, respectively. 5 In areas subject to pronounced super-refraction phenomena, account should be taken of the information contained in Annex 1, 18. 6 The ionosphere, primari
48、ly through the effects of sporadic-E ionization, can influence propagation in the lower part of the VHF band, particularly at frequencies below about 90 MHz. In some circumstances this mode of propagation may influence the field strength exceeded for small percentages of the time at distances beyond
49、 some 500 km. Near the magnetic equator and in the auroral zone, higher percentages of the time may be involved. However, these ionospheric effects can usually be ignored in most applications covered by this Recommendation and the propagation curves of this Annex have been prepared on this assumption. (Recommendation ITU-R P.534 provides guidance on sporadic-E propagation.) 6 Rec. ITU-R P.1546-5 FIGURE 1 100 MHz, land path, 50% time P.1546-011 200 m600 m300 m150 m75 m20 m10 m1201101009080706050403020100102030405060708010 100 1 000h1= 1
