1、STD-CEPT ERC REPORT 39-ENGL 399b 9 2326434 0035521 858 ERC REPORT 39 European Radiocommunications Committee (ERC) within the European Conference of Postal and Telecommunications Administrations (CER) .,. -. _-. POSSIBILITY OF SHARING BETWEEN FIXED LINKS AND SNG IN THE 14.25 - 14.5 GHz BAND Rome, Oct
2、ober 1996 STD-CEPT ERC REPORT 39-ENGL 399b 232b414 0035522 794 = Copyright 1996 the European Conference of Postal and Telecommunications Administrations (CEPT) STD.CEPT ERC REPORT 39-ENGL 199b 232h414 0015523 620 ERC REPORT 39 Page 1 POSSIBILITY OF SHARING BETWEEN FIXED LINKS AND SNG IN THE 14.25 -
3、14.5 GHz BAND 1. BACKGROUND The frequency band 14.25 - 14.5 GHz is allocated in Europe with a primary status to the Fixed Service together with the Fixed Satellite Service (uplink). There are at least four CEPT countries currently using this band for FS: France, Germany, Italy and UK. Germany announ
4、ced that they intend to relocate. their transportable fixed links in another band in case of unacceptable interference to the fixed service. It has been envisaged that VSAT and SNG be used in this band. In particular, SNG operators are keen to have the opportunity of using EBU transponders operating
5、 in this frequency band. A SE19 report and a French contribution previously presented at SE meetings concluded that the shkng between FS and uncoordinated VSAT or SNG was not feasible. On the other hand, interfering distances were considered sufficiently short to enable the operation of SNG in coord
6、inated or precoordinated sites. 2. COORDINATION PROCEDURES BETWEEN SNG AND THE FIXED SERVICE Two countries, France and UK, have successfully defined coordination procedures enabling SNG to coordinate with fixed links. The French procedure aims to coordinate regularly used sites. In the case of speci
7、al events not in regularly used sites, but which are known in advance, the same procedure applies. The UK procedure will also enable SNG to operate if they are outside coordination zones surrounding all FS receivers. Additionally, SNG operations could be allowed from within a coordination zone when
8、sufficient path loss exists between the SNG transmitter and the FS receiver. This path loss will be assessed from measurements of the power received at the SNG location, emitted by the FS transmitter. The detailed French and UK procedures are provided in Annex 1 and Annex 2. 3. CHANNEL ARRANGEMENTS
9、Included within this report in Annex 3 is a possible radio frequency channel mangement for the band 14.25 - 14.5 GHz, which has been adopted by some countries. This channel plan will assist in the sharing and compatibility studies with other services. 4. CONCLUSION Despite their differences, these t
10、wo coordination procedures are demonstrating that it is possible to arrange sharing between SNG and the Fixed Service in the 14.25 - 14.5 GHz band. The coordination procedures applied to SNC could also be applied to VSATs. It can therefore be concluded that coordinated VSATs can also share the 14.25
11、 - 14.5 GHz band. ERC REPORT 39 Page 3 ANNEX 1 DESCRIFTION OF FRENCH METHOD OF COORDINATION 1. INTRODUCTION A steadily increasing network of more than 600 digital fixed links (FL) in the band 14.25 - 14.5 GHz implemented all over the country made compulsory a coordination procedure when it was decid
12、ed in France to authorise, in the same band, the operation of transmitting earth stations (ES) for satellite news gathering (SNG). 2. THE DIFFERENT STEPS IN THE PROCEDURE The aim followed here is to identify regularly or permanently used or envisaged SNG sites and clear them to transmit in the band
13、14.25 - 14.5 GHz providing they meet the specifications established for the protection of the reception of existing or pkinned fixed links in the same band. 2.1. In this context the first step was made by the DGPT, the French regulatory body, which sent a questionnaire to all the operators likely to
14、 be interested in SNG operation, asking them to indicate the concerned events which would need the use of SNGs with detailed information on location, duration, vatellites and frequencies envisaged. The information provided by the interested operators enabled the DGPT to draw a list of sites, sorted
15、by date of occurrence of the programmed events. For example, the rss events on the list are the Cannes festival (05/95), Roland Garros tennis tournament (04/95), Palais de Elyse in Paris / Presidentid elections (05/9$). 2.2. Because the interested operators are rarely able to provide precise informa
16、tion about the exact location from which the ES will transmit, a visit of the site by the team working for the DGPT is almost always necessary. In this manner, more information is obtained from the authority responsible for the organisation of the event about the location of the area dedicated to th
17、e installation of the transmitting equipment. GPS is then used to confirm the coordinates given by the operator (to 100 m accuracy) and a precise elevation of the horizon in all azimuths (from o“ to 359“) from the specified area(s) is established. When necessary, pictures of important azimuths are t
18、aken. 2.3. By use of purpose designed software, a calculation is then carried out. It enables the identification of all the FLs potentially interfered by the planned ES and the consequent constraints concerning the satellites that can be identified, Le.: the range of frequencies; the maximum E.I.R.P
19、. (including the diameter of the ES antenna); and the dedicated area while transmitting. 2.4. This information forms the basic elements of the response sent by the DGPT to the applicant. In the case of a permanent clearance given to the site, this information will also be used to establish the offic
20、ial documents which will be the requirements any SNG operator must meet. Hence, any extension of the existing FL network will take into account the presence and the characteristics of the ES, considered as permanent. 3. NECESSARY TECHNICAL PARAMETERS In order to calculate the potential interference
21、caused to the FL receivers by the transmitting ES certain technical parameters concerning each service (FS and FSS) have to be entered in the software. ERC REPORT 39 Page 4 3.1. ES parameters Unless different parameters are given by the applicant operator, the set of parameters concerning the ES use
22、d for the calculation is described below: antenna diameter maximum antenna gain antenna pattern maximum antenna height maximum E.I.R.P. maximum bandwith frequency range pointing 2.4 m 48 dBi meets ETSI ETS 300 327 requirements 8 meters above ground 78 dBW 36 MHz GE0 arc from 50“W to 63“E 14250 - 145
23、00 MHz Coordinates and altitude of the site including elevation of the horizon in all azimuths are also introduced in the software. 3.2. FLs parameters All the existing and planned fixed links are described in the database connected with the software. So, the parameters attached to them used during
24、the calculation are not generic but correspond to the reality. The main characteristics are listed below: coordinates and altitude of the FL transmitting and receiving stations antenna diameter antenna gain antenna diagram antenna height above the ground feeder losses connection losses attenuator (i
25、f used) FKTB of the receiving equipment carrier frequency and bandwidth 3.3. Geographical parameters The data terrain model from the National Geographic Institute is also used to determine the influence of the natural masks, when they exist, between the ES and the interfered FI. 4. CALCULATION PROCE
26、SS The rule followed to determine if a FL receiver is harmfully interfered by the planned ES is to check that the level of interference arriving at its flange is at least 10 dB lower than the FKTB. ITU-R 847 and 526 are mainly used in this process. In the first step, only the free space propagation
27、model on a supposed flat earth is used. This lists all the potentially interfered fixed links, taking into account the antennas discrimination, connection and feeder losses. In the second step, the calculation takes into account the additional attenuation linked to the correction due to the effectiv
28、e angle of horizon in the direction of the interfered FL receivers and provides modified levels of interfe- rence. STD*CEPT ERC REPORT 39-ENGL 197b 232b41Y 001552b 33T D ERC REPORT 39 Page 5 If it appears that a FL would suffer interference, the use of data terrain model gives the value in dB of the
29、 loss from natural obstacles between the ES and the receiver of the FL. In this case, the correction due to the angle of the horizon is no longer taken into account. The initial levels of interference are consequently modified. If it still appears that a FL receiver would suffer interference, it bec
30、omes necessary to determine the less stringent constraints for the applicant. Depending on the case, it can affect the frequency range, the pointing range on the CEO arc, the maximum E.I.R.P., etc. The ES and its parameters (including the eventual constraints) are registered in the data base and wil
31、l be taken into account if any extension of the FLS network is to be planned. 5. FIRST RESULTS Up to April 1995, about ten sites had been successfully studied, mainly in the region of Paris. In only two cases, relatively minor restrictions concerning the E.I.R.P. or the pointing range had to be spec
32、ified to the applicants. Some of the ESs are already in action, and no quality impairment of the FLs has been reported. These first encouraging results are mainly due to the presence of a relatively high protection provided by artificial masks (buildings) around the planned sites. 6. CONCLUSION The
33、coordination process described here is one of the solutions enabling FLs and programmed SNG transmitting ESs to share the band 14.25 - 14.5 GHz. The first results give the feeling that this method works well, providing that some elementary engineering rules applied to ESs are respected, particularly
34、 in looking for sites surrounded by natural or artificial obstacles. STD-CEPT ERC REPORT 39-ENGL 1996 - 2326414 0015527 27b = 1. 2. 2.1. 2.2. 3. 3.1. ERC REPORT 39 Page 7 ANNEX 2 DESCRIPTION OF UK METHOD OF COORDINATION INTRODUCTION The frequency band 14.25 - 14.5 GHz is used in the LJK for point-to
35、-point terrestrial Fixed Links (FLs) and for satellite uplinks from permanent and Transportable Earth Stations (TESs). Arrangements already exist to coordi- nate permanent earth stations with FLs, but there is potential for TESs to cause interference to FL receivers. This document describes the proc
36、edures to be adopted by the Radiocommunications Agency (RA) and K TES operators to minimise the risks of causing interference. REGULARLY USED TES SITES Some sites are used by TES operators on a regular, predictable basis. Exampies of such sites are racecourses and sports stadiums. The RA will clear
37、these sites for TES operation and fixed links will be coordinated with the site as if a permanent earth station existed. Generic TES parameters A generic set of TES parameters are required to coordinate Regularly Used Sites. Antenna gain pattern Antenna gain E.I.R.P. Max power density into antenna M
38、ax bandwidth Frequency range Antenna height Pointing RE. ITU-R S.465 47 dBi 12 dBW 40.5 dBW/Hz 36 MHz 4m agl Whole GE0 arc above 20“ elevation 14.0 - 14.5 Gfi Treatment of Regularly Used Sites A site defined as “Regularly Used“ will be coordinated with existing fixed links in the conventional manner
39、. New fixed links will need to coordinate with the Regularly Used Site assuming the generic TES parameters. New fixed links may still be licensed even if it is predicted that the FL receiver would suffer interference bom a TES. The FL operator could choose to accept such an allocation, but cannot ex
40、pect protection from the TES operating within the generic TES parameters. UNPREDICTABLE TES SITES A large number of TES sites cannot be coordinated in advance. For applications such as Satellite News Gathering, clearance is required quickly at new and unpredictable sites. To perform this task, the R
41、A rapid clearance system will coordinate proposed TES sites with fixed link receivers. Space Coordiiiation The clearance procedure will be implemented on the RA rapid clearance system. The coordination with fixed links will be performed using a software tool TLATCO“. FLATCO (Fixed Jjnk and ES -ordin
42、ation) is the name given to the software tool which the RA coordinator will use to assist in coordination of TESs with fixed links. This tool is currently being developed. STD=CEPT ERC REPORT 39-ENGL 1996 - 2326414 0015528 102 W so ERC REPORT 39 Page 8 I l I I I SI The TES operator will include the
43、following parameters in his application to the RA I Intended location (National Grid Reference) Frequency Transmission bandwidth Analogue or digital modulation The RA coordinator Will enter the TES parameters into FLATCO and will be shown a map of the surrounding Xed indicating the proposed position
44、 of the TES and coordination zones of nearby, affected fKed links. If the proposed TES position is within a coordination zone, the TES operator may choose to try a different transmission frequency or try a different location. The coordinator will be able to suggest alternative sites. Using an assume
45、d antenna mask of 32 - 25 log cp (dBi) and a minimum elevation of 20”, the TES antenna gain in the direction of any fixed link is assumed to be -0.5 dBi. If the TES is using analogue modulation, the e.i.r.p. density in the direction of any fixed link is assumed to be -40 dBW/Hz. If the TES is using
46、digital modulation, the e.i.r.p. density is assumed to be -49 dBW/Hz. The interference criterion for the futed link has been determined, noting that the TES transmits from any location for short periods of time. The critenon for most fixed links is a I/N threshold of 9 dB. (For a few links with a fd
47、de margin less than 16 dB, the threshold is reduced). The actual sidelobe performance of a fixed antenna is often much better than the mask in the type approval specification. Manufacturers guaranteed antenna masks will be used where possible. An implementation of Recommendation ITU-R PN.452 will be
48、 used for the propagation model. This will include an addition for clutter loss, dependent on the type of terrain. 3.2. Frequency Coordination Another coordination method is the ability of the TES operator to select a transmission kequency which purposefully avoids the nearby Fi, receiver frequencie
49、s. It is recognised that a choice of frequency is not available to most TES operators. However, judicious frequency selection is a simple and effective coordination method and full advantage should be taken where possible. Tables are available (in the RAS MP specifications) which model the performance of the fixed link receiver filter in combination with the interfering signal spectrum. These tables can be used to estimate the isolation introduced by a frequency offset between wanted and unwanted carrier. An example is shown in Figure 1. dB I I I I ! I I Figure 1
