1、 Recommendation ITU-R P.620-7 (06/2017) Propagation data required for the evaluation of coordination distances in the frequency range 100 MHz to 105 GHz P Series Radiowave propagation ii Rec. ITU-R P.620-7 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, effic
2、ient and economical 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
3、 performed 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. F
4、orms to be 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
5、 be found. 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 Mobi
6、le, radiodetermination, 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 mana
7、gement SNG 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, 2017 ITU 2017 All rights reserved. No par
8、t of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R P.620-7 1 RECOMMENDATION ITU-R P.620-7* Propagation data required for the evaluation of coordination distances in the frequency range 100 MHz to 105 GHz (Question ITU-R 208/3) (1986-1992-1
9、995-1997-1999-2003-2005-2017) Scope This Recommendation contains a prediction method for the determination of the coordination area around an earth station in the frequency range 100 MHz to 105 GHz. Prediction methods are provided to calculate the coordination area during periods of both clear air a
10、nd scatter from hydrometeors (e.g. rain scatter). Keywords Coordination area, Coordination distance, Clear air, Hydrometeor scatter The ITU Radiocommunication Assembly, considering a) that the coordination area is that area, around an earth station, so defined that any interference between the earth
11、 station in question and terrestrial stations outside this area may be considered as negligible; b) that the determination of the coordination area should be based on the best propagation data available and should be adequately conservative; c) that the World Radiocommunication Conference (Istanbul,
12、 2000) (WRC-2000) approved a revision of Appendix 7 of the Radio Regulations (most recently updated at WRC-15) based on material in Recommendation ITU-R SM.1448 which in turn is based on material in Recommendation ITU-R P.620 covering the frequency range 100 MHz to 105 GHz; d) that Resolution 74 (WR
13、C-03) describes a process to keep the technical bases of Appendix 7 current, recommends that, for the determination of the coordination area with respect to frequencies above 100 MHz, administrations use the propagation calculation methods set out in Annex 1. * This Recommendation should be brought
14、to the attention of Radiocommunication Study Group 1. 2 Rec. ITU-R P.620-7 Annex 1 1 Introduction This Annex provides propagation data for use in the calculation of a coordination area and sets out a straightforward method for the assessment of the propagation factors concerned in the determination
15、of coordination distances. The coordination area represents the area outside of which interference between an earth station and terrestrial stations (or between bidirectionally operating earth stations), operating within the conservative assumptions given elsewhere, may be considered negligible. In
16、the remainder of this Recommendation the words terrestrial stations may also represent bidirectionally operating earth stations. The determination of coordination distance therefore necessitates the comparison of the required transmission loss (minimum permissible basic transmission loss, Lb( p) (dB
17、), not exceeded for a given annual percentage time p), based on system and interference model considerations, with the transmission loss contributed by the propagation medium. The required coordination distance is that at which these two losses become equal. Various propagation models are provided t
18、o cover different frequency ranges and to take account of different propagation mechanisms. These models predict propagation loss as a function of distance. Coordination distances are determined by calculating propagation loss iteratively with distance until either the required transmission loss is
19、achieved or a limiting distance is reached. It is important to note that the coordination area does not represent a zone within which the sharing of frequencies between the earth station and the terrestrial station is excluded. Such sharing is often possible, and the coordination area serves to assi
20、st this arrangement by indicating where the potential for interference between the earth station and any terrestrial stations needs to be evaluated using a more detailed analysis based on the relevant ITU-R Recommendations. In addition to providing the method of calculation for the coordination cont
21、our, this Recommendation also provides information that enables the preparation of auxiliary contours to assist in the rapid elimination of the majority of potential interference cases during the subsequent coordination analysis for terrestrial stations falling within the coordination contour. 2 Str
22、ucture of the Recommendation The structure of the Recommendation is as follows: Annex 1: The overall methodology for determining the coordination area Attachment 1 to Annex 1: The definition of the input parameters Attachments 2 and 3 to Annex 1: The equations required to calculate the coordination
23、contours Attachment 4 to Annex 1: A reference radiation pattern for line-of-sight radio-relay system antennas Attachment 5 to Annex 1: The definition of all parameters. 3 General considerations 3.1 Assumptions The determination of coordination distance propagation characteristics for an earth statio
24、n is based on the assumption that: Rec. ITU-R P.620-7 3 the locations of terrestrial stations with which coordination is to be sought are not known; in the interference path geometry, only information pertaining to the earth station is available; for the geometry over the remainder of the interferen
25、ce path, cautious limiting assumptions must be made as shown in the following text. In this Annex, propagation phenomena are classified into two modes as follows: mode (1): propagation phenomena in clear air: affected by the presence of the Earths surface (diffraction, refraction, ducting and layer
26、reflection/refraction), and via tropospheric scatter. These phenomena are confined to propagation along the great-circle path; mode (2): hydrometeor scatter, which is not limited to the great-circle path, but is, as dealt with in this Annex, limited to earth stations operating with geostationary sat
27、ellites. For each azimuth from the earth station, and for each of the above two modes of propagation, it is necessary to determine a distance which gives a propagation loss equal to the required minimum permissible basic transmission loss. This distance (coordination distance) will be the greater of
28、 the two distances found. The iteration method can always use a uniform step size, 1 km being recommended. In the case of mode (1) the functions defining propagation loss are monotonic with distance and, if preferred, a more efficient iteration procedure may be used. 3.2 Overview of propagation mode
29、ls For the determination of coordination distances for propagation mode (1), the applicable frequency range has been divided into three parts: for VHF/UHF frequencies between 100 MHz and 790 MHz the model is based on an empirical fit to measured data; from 790 MHz to 60 GHz a propagation model takin
30、g account of tropospheric scatter, ducting and layer reflection/refraction is used; from 60 GHz to 105 GHz a millimetric model, based upon free-space loss and a conservative estimate of gaseous absorption, plus an allowance for signal enhancements at small time percentages, is used. The parameter in
31、put ranges for each of the propagation mode (1) model mechanisms are in general different. For the determination of coordination distances for propagation mode (2), isotropic scattering from hydrometeors in the common volume formed by the main beams of the potentially interfering stations is modelle
32、d. For the purposes of frequency coordination at frequencies below 1 GHz and above 40.5 GHz interference produced by hydrometeor scatter can be ignored. Below 1 GHz the level of the scattered signal is very low and above 40.5 GHz, although significant scattering occurs, the scattered signal is then
33、highly attenuated on the path from the scatter volume to the terrestrial station. For mode (1) the distance is incremented from a specified minimum which varies according to propagation factors relevant to each frequency range. For mode (2) distance is decremented from a maximum given in Table 2. Fo
34、r auxiliary mode (2), distance is decremented from the main mode (2) coordination distance for the same azimuth. 4 Rec. ITU-R P.620-7 The loss due to shielding by terrain around an earth station should be calculated by the method described in 1 of Attachment 2 according to the horizon elevation angl
35、es along different radials from the earth station. For all frequencies between 100 MHz and 105 GHz this additional loss should be taken into account. 4 Radio-climatic information 4.1 Radio-climatic data For the calculation of the coordination distance for propagation mode (1), the world has been cla
36、ssified in terms of radio-climatic zones (see 4.2) and a radiometeorological parameter, p, which reflects the relative incidence of clear-air anomalous propagation conditions. The value of p is latitude dependent. The latitude to be used in determining the correct value for p is given by: 8.1f o r0
37、8.1f o r8.1rb)1()a1( where is earth station latitude (degrees). p is then determined using: 70orf17.4 70orf01 015.067.1rrp r )b2( )a2( For frequencies between 790 MHz and 60 GHz the path centre sea level surface refractivity, N0, is used in the propagation mode (1) calculations. This can be calculat
38、ed using: 27.32 20 e6.62330 N (3) 4.2 Radio-climatic zones In the calculation of coordination distance for propagation mode (1), the world is divided into four basic radio-climatic zones. These zones are defined as follows: Zone A1: coastal land and shore areas, i.e. land adjacent to a Zone B or Zon
39、e C area (see below), up to an altitude of 100 m relative to mean sea or water level, but limited to a maximum distance of 50 km from the nearest Zone B or Zone C area as the case may be; in the absence of precise information on the 100 m contour, an approximation (e.g. 300 feet) may be used; Zone A
40、2: all land, other than coastal land and shore defined as Zone A1 above; Zone B: cold seas, oceans and large bodies of inland water situated at latitudes above 30, with the exception of the Mediterranean and the Black Sea; Zone C: warm seas, oceans and large bodies of inland water situated at latitu
41、des below 30, as well as the Mediterranean and the Black Sea. The following zone distance parameters are required in the various frequency models: dlm (km): longest continuous inland distance, Zone A2, within the current path distance; dtm (km): longest continuous land (i.e. inland coastal) distance
42、, Zone A1 Zone A2 within the current path distance. Rec. ITU-R P.620-7 5 Where necessary, these distances must be re-evaluated for each total path distance within the iteration loops of the propagation models. Large bodies of inland water A large body of inland water, to be considered as lying in Zo
43、ne B or Zone C as appropriate, is defined for the administrative purpose of coordination as one having an area of at least 7 800 km2, but excluding the area of rivers. Islands within such bodies of water are to be included as water within the calculation of this area if they have elevations lower th
44、an 100 m above the mean water level for more than 90% of their area. Islands that do not meet these criteria should be classified as land for the purposes of the water area calculation. Large inland lake or wetland areas Large inland areas of greater than 7 800 km2 which contain many small lakes or
45、a river network should be declared as coastal Zone A1 by administrations if the area comprises more than 50% water, and more than 90% of the land is less than 100 m above the mean water level. Climatic regions pertaining to Zone A1, large inland bodies of water and large inland lake and wetland regi
46、ons are difficult to determine unambiguously. Therefore administrations are invited to register with the ITU Radiocommunication Bureau (BR) those regions within their territorial boundaries that they wish identified as belonging to one of these categories. In the absence of registered information to
47、 the contrary, all land areas will be considered as pertaining to climate Zone A2. 4.3 Use of radio-climatic information from other Recommendations In certain sections for both mode (1) and mode (2) calculations, reference is made to radio-climatic information obtained from other ITU-R Recommendatio
48、ns. These are: a) Recommendation ITU-R P.836 for water vapour density; b) Recommendation ITU-R P.837 for rain rate; c) Recommendation ITU-R P.839 for rain height. These Recommendations are referenced where necessary to obtain a radio-climatic parameter for a particular location defined by longitude
49、and latitude. In other parts of the mode (1) and mode (2) calculations constant values of some radio-climatic parameters are used. In these cases no reference is needed to the other Recommendations. 5 Distance limits 5.1 Minimum distance limits The coordination distance in any given direction is determined by a number of factors set out above and, based on propagation factors alone, the distances could extend from relatively close-in to the earth station to many hundreds of kilometres. However, for pr
