1、ITU-R RECMN*S. 1063 94 4855212 0523446 444 260 Rec. ITU-R S.1063 RECOMMENDATION ITU-R S. 1063 CRITERIA FOR SHARING BETWEEN BSS FEEDER LINKS AND OTHER EARTH-TO-SPACE OR SPACE-TO-EARTH LINKS OF THE FSS (Question ITU-R 210/4) (1994) The ITU Radiocommunication Assembly, considering a) broadcasting-satel
2、lite service (BSS) are part of the fixed-satellite service (FSS); that under the Radio Regulations (RR) the Earth-to-space links used as feeder links to satellites in the b) that the frequency and technical characteristics of such feeder links may depend on the technical characteristics of systems u
3、sing the broadcasting satellite, but that risks of interference with satellites in the FSS providing links between specified points on the Earth should also be taken into account; c) for links between earth stations; that the system constraints of the BSS may affect the efficiency with which the FSS
4、 frequency bands are used d) that the following Earth-to-space FSS frequency bands have been identified for use by BSS feeder links; 10.7-11.7 GHz (Region l), 14.5-14.8 GHz (all Regions except Europe), 17.3-17.8 GHz (Region 2 also allocated to the BSS), 17.3-18.1 GHz (Regions 1 and 3), 18.1-18.4 GHz
5、 (ali Regions by Footnotes RR 870A and 870B), 24.75-25.25 GHz (Regions 2 and 3), 27.5-30.0 GHz (all Regions); e) Appendix 30, that certain BSS feeder links are planned as in RR Appendix 30A to pair with the BSS Plan of RR recommends 1. 1.1 that when considering sharing between the FSS and BSS feeder
6、 links: the requirements and constraints of both systems should be taken into account; z.2 1.3 reducing the required bandwidth of the feeder links should be considered; suitable interference calculations should be performed and results compared against required protection ratios; 2. that the factors
7、 and examples given in Annex 1 be considered to help facilitate 9 1. ANNEX 1 Criteria for sharing between BSS feeder links and other Earth-to-space or space-to-Earth links of the FSS 1. Introduction Frequency bands allocated to the BSS are, by definition, in the space-to-Earth direction. Feeder link
8、s to broadcasting satellites, operating in any frequency band must, under the current provisions of the Radio Regulations, use the Earth-to-space allocations of the FSS. For the purpose of this Annex, the term “fixed-satellite service” is as defined in the Radio Regulations, but excludes feeder link
9、s to broadcasting satellites. ITU-R RECMN*S= Lab3 74 4655232 O523447 380 = Rec. ITU-R S.1063 261 The World Administrative Radio Conference (Geneva, 1979) (WARC-79), and subsequently the World Administrative Radio Conference for Dealing with Frequency Allocations in Certain Parts of the Spectrum (Mal
10、aga-Torremolinos, 1992) (WARC-92), allocated a number of Earth-to-space bands for use by feeder links for the BSS. These bands are: 10.7-1 1.7 GHz (Region l), 14.5-14.8 GHz (all Regions except Europe), 17.3-17.8 GHz (Region 2, this band is also allocated to the BSS), 17.3-18.1 GHz (Regions 1 and 3),
11、 18.1-18.4 GHz (all Regions by Footnotes RR 870A and 870B), 24.75-25.25 GHz (Regions 2 and 3), 27.5-30.0 GHz (all Regions). Since, however, the up-link requirements of the BSS, particularly around 12 GHz, are expected to be fairly substantial and feeder links for broadcasting satellites may be drawn
12、 from any fixed-satellite Earth-to-space allocation (though subject to coordination in bands not exclusively designated for feeder links), and since the higher frequency bands for that purpose may be unattractive to some administrations, the problem of using Earth-to-space allocations by both the FS
13、S and the BSS remains a matter of concern. The simultaneous use of the 14 to 14.5 GHz band by broadcasting-satellite systems and around 12 GHz by the FSS having different space-to-Earth allocations will be a problem in congested parts of the orbit. In addition to individual and community type BSSs i
14、n the 12 GHz band, it is envisioned that interactive services (voice, data and video) may be provided through the use of earth stations with small aperture antennas. This may place additional requirements and constraints on both services. This Annex evaluates the impact of sharing, associated with u
15、sing fixed satellite allocations for feeder links to broadcasting satellites with regard to the Plans developed by the World Administrative Radio Conference for the Planning of the Broadcasting-Satellite Service, (Geneva, 1977) (Regions 1 and 3) (WARC BS-77), the related subsequent Regional Administ
16、rative Radio Conference for the Planning of the Broadcasting-Satellite Service in Region 2 (RARC SAT-R2) (Geneva, 1983), and the BSS feeder-link plan for Regions 1 and 3 developed at the Second Session of the World Administrative Radio Conference on the Use of the Geostationary-Satellite Orbit and o
17、n the Planning of Space Services Utilizing It (Geneva, 1988) (WARC ORB-88). 2. Technical and operational characteristics required for feeder links to broadcasting satellites 2.1 Broadcasting-satellite systems around 12 GHz The WARC BS-77 established certain technical standards which affect the feede
18、r links for Regions 1 and 3. One important requirement is that the reduction in the quality in the down-link due to thermal noise in the feeder link is taken to be equivalent to a degradation in the down-link CIN not exceeding 0.5 dB for 99% of the worst month. To limit the impairment to this value,
19、 the CIN on the feeder link must be about 10 dB higher than that required for the down-link CIN, which in this case would mean a feeder link CIN of up to 24 dB, if the modulation indices were the same. WARC BS-77 also established a value of 30 dB as the total protection ratio to which each broadcast
20、ing satellite transmission must be protected. Similarly, with the division of overall performance requirements, the total protection ratio of the feeder link of a broadcasting satellite may have to be of the order of 40 dB, with a single-entry protection ratio which may be as high as 45 dB. Standard
21、s for either of these two latter values have not yet been established. For interference caused by the adjacent channels, recent simulation experiments have shown that the operation of broadcasting-satellite power tubes at saturation reduces interference received from the adjacent channels by about 4
22、 dB relative to that observed under reduced-drive conditions of the power tube. This improvement may also benefit adjacent-channel interference planning of feeder links in Regions 1 and 3. For Region 2, the RARC SAT-R2 concluded that an overall co-channel protection ratio of 28 dB is required, and t
23、hat is reflected in the development of the Region 2 Plan. Also, it was decided that, for feeder links, a noise temperature increase of 10% at satellite receiver input should be the threshold which, if exceeded by actual interfering emissions, would require coordination. Further information is to be
24、found in Recommendations ITU-R B0.793, ITU-R B0.794 and ITU-R B0.795 in RR Appendix 30, and in the Final Acts of the RARC SAT-R2 (Geneva, 1983). ITU-R RECMNxS. I1063 94 = 4855232 0523448 237 262 Rec. ITU-R 5.1063 3. Feeder link bandwidth requirements 3.1 Down-link allocations The feeder link bandwid
25、th requirement has to be viewed in the context of the overall bandwidth allocated to the BSS. These are summarized in Table 1 TABLE 1 Bandwidth allocated to the BSS below 40 GHz Part of the spectrum 700 MHz 2.5 GHz 12 GHz 17 GHz 21 GHz Amount of bandwidth (MHz) 170 190 800 (Region 1) 500 (Region2) 5
26、00 + 250 (Region 3) 500 (Region 2) 600 (Regions 1 and 3) 3.2 Reduction of bandwidth required for feeder links to 12 GHz broadcasting satellites Substantial bandwidth has been allocated to the BSS for its space-to-Earth links, and it is foreseen that these bands will ultimately be used extensively fo
27、r television with frequency re-use obtained by means of high-gain satellite transmitting antennas and the use of cross-polarization techniques. A similar measure of frequency re-use will, no doubt, be obtained in the feeder link direction by means of high-gain satellite receiving antennas, but it is
28、 doubtful whether this technique can provide a significantly greater degree of frequency re-use in the feeder link than in the downlink, in parts of the world where broadcasting coverage areas are relatively small. The usage of the fixed-satellite Earth-to-space bands for broadcasting satellite feed
29、er links could be reduced if means could be found for a further measure of frequency re-use in the feeder link. Four possible ways of achieving this have been identified: - Feeder link frequency re-use using the higher directivity of the transmitting earth-station antenna, relative to broadcast rece
30、iving antennas. - Dual polarization. - Alternative modulation methods for the feeder links. - Integrated sound-vision systems. 4. Feasibility of sharing allocations to the FSS (Earth-to-space) with feeder links for the BSS 4.1 Use of the 14.0 to 14.5 GHz band An example is used to demonstrate interf
31、erence by a broadcasting-satellite service feeder-link transmission to a satellite with INTELSAT-V characteristics, and the reverse situation of interference by a fixed-satellite service up-link transmission to a broadcasting-satellite feeder link. The interfering signais are assumed to be Co-freque
32、ncy and Co-polarized. ITU-R RECMNrS. Lob3 94 = 4855232 0523449 153 Satellite receiving system Rec. ITU-R S.1063 Transmit earth station 263 Beam edge GIT (WK-) 6 O -6 The following are the system assumptions made in the example for the two interfering signals; Regarding the broadcasting-satellite up-
33、link transmissions: Satellite receive antennas beamwidths: Satellite receiving system noise temperature: Transmit earth station diameter: Uplink carrierhoise ratio: 25 dB RF bandwidth: 27 MHz Energy dispersal: 600 kHz peak-to-peak These assumptions result in the following consequential system parame
34、ters (at 14 GHz): 1 O, 2“, 4“ 3 000 K 2,4, 8 m Power into antenna (W 2m 4m 8m 72.7 3 80 97 24 78.7 1500 380 97 84.7 6000 1500 380 e.i.r.p. (dBW TABLE 2 Antenna beamwidth (degrees) I 1 2 4 I Type Modulation A FDM-FM B FDM-FM C CQPSK-TDMA e.i.r.p. Protection ratio (dBW (dB) Capacity 24 channels 69 29(
35、) 972 channels 81 33() 120 Mbitls 82 30(*) Regarding the INTELSAT system, three representative transmission types will be assumed, with the following characteristics: TABLE 3 (I) To produce 600 pWOp of noise power in the worst channel due to interference from an analogue FM-TV (2) Minimum permissibl
36、e for a single entry from any high power transmission contained within the occupied transmission. band of 72 MHz. Assuming coincident or overlapping 14 GHz space station receive antenna coverages of both a broadcasting-satellite and an INTELSAT-V, and assuming further that the earth stations transmi
37、tting to the broadcasting-satellite meet the ITU-R reference earth-station antenna pattern; compliance with the required protection ratios given above would necessitate the geocentric angular separations, as given in Table 4, between the broadcasting-satellite and an INTELSAT-V: The advantages of de
38、creased broadcasting-satellite receiving antenna beamwidth in reducing interference conditions are clearly shown, however, the reduced coverage could prevent transmission to the broadcasting-satellite from certain areas within the boundaries of the service area, or from outside the service area. ITU
39、-R RECMN*S. LO63 9Y m YB55212 0523Y50 775 m Characteristics of the broadcasting-satellite system Satellite antenna receive Transmitting earth beamwidth station antenna diameter (degrees) (m) 2 1 4 8 2 2 4 8 2 4 4 8 264 Rec. ITU-R S.1063 Spacings for interfered-with satellites INTELSAT carrier types
40、(degrees) A B C 24 channels 972 channels Q-CPSK FDM-FM FDM-FM 120 Mbih 5.0 2.4 1.7 2.9 1.4 1.0 1.7 1.0 1.0 8.7 4.2 2.9 5.0 2.4 1.7 2.8 1.4 1.0 15.1 7.2 5.0 8.7 4.2 2.9 5.0 2.4 1.7 TABLE 4 Broadcasting satellite received beamwidth (degrees) 1 2 4 Satellite spacings for different INTELSAT transmit ear
41、th-station diameters (degrees) 8m 12 m 16 m 11.6 8.8 6.8 6.7 5.0 4.0 3.8 3.0 2.3 Present INTELSAT planning provides for an appreciable number of FDM-FM carriers of only 24 channels capacity with numerous FDM-FM carriers having capacities anywhere between 24 and 972 channels. The geocentric angular s
42、eparations required between a broadcasting-satellite and an INTELSAT-V are, for such carriers, appreciable. They might be achievable if broadcasting-satellites were spaced from each other by twice the above angles, but that would result in only just one fixed-service satellite location alternating w
43、ith one broadcasting-satellite location. Where a ratio of n fixed-service satellites to one broadcasting-satellite would be desirable, the broadcasting-satellite spacing would have to be further increased by n - 1 times the spacing required between the fixed-service satellites. One could, with the I
44、NTELSAT system, take advantage of the fact that it provides currently only limited up-link (14 GHz) coverage and use for broadcasting-satellite feeder links, satellite receive beams of less than 1“ beamwidth, and transmit earth stations of greater than 8 m antenna diameter to alleviate the problem,
45、but this could be a severe constraint on the broadcasting-satellite service and may not be acceptable. Alternatively, one might align carrier frequencies between broadcasting-satellite feeder links and INTELSAT-V carriers, or attempt to realize some up-link polarization discriminations. In the other
46、 direction, interference from fixed-satellite service earth stations into broadcasting-satellites is far from negligible. With the parameters for the INTELSAT 972-channel carrier and an assumed required single entry protection ratio of 45 dB in the broadcasting-satellite service feeder links, the fo
47、llowing geocentric satellite separations would be required at 14 GHz: TABLE 5 - ITU-R RECMNxS- 3063 74 4855232 0523453 BOL = Rec. ITU-R S.1063 265 The system parameters given in this section for the FSS are those of INTELSAT-V. Other systems in the FSS, particularly those intended for domestic and r
48、egional service, may require greater spacings than those indicated in the tables. In this case an increase in the sensitivity of the broadcasting-satellite receiver correspondingly increases its sensitivity to interference from transmissions of earth stations in the FSS, and may result in increased
49、satellite spacing requirements. It may be concluded that interference problems could arise between up-links of FSS systems and feeder links to broadcasting-satellites when they use a common frequency band. However, specific solutions to these problems may be available through frequency coordination and the use of appropriate technology. It is concluded that individual cases of sharing between networks in the FSS and broadcasting-satellite feeder links require detailed examination, taking into account the projected design and operating parameters. Two additional examples are given
