1、 Rec. ITU-R S.1780 1 RECOMMENDATION ITU-R S.1780*Coordination between geostationary-satellite orbit fixed-satellite service networks and broadcasting-satellite service networks in the band 17.3-17.8 GHz (2007) Scope This Recommendation addresses the issue of inter-system coordination between broadca
2、sting-satellite service (BSS) networks serving Region 2 and fixed-satellite service (FSS) networks serving Regions 1 and/or 3 in all or part of the frequency band 17.3-17.8 GHz. This issue arises as a consequence of the introduction of the primary BSS allocation in Region 2 as of 1 April 2007, and t
3、he existing primary space-to-Earth FSS allocation in Region 1 (17.3-17.8 GHz) and Region 3 (17.7-17.8 GHz). Representative FSS and BSS system characteristics are considered in order to perform a technical analysis of the coordination requirements. The ITU Radiocommunication Assembly, considering a)
4、that, per No. 5.517 of the Radio Regulations (RR), as of 1 April 2007 the broadcasting-satellite service (BSS) allocation in Region 2 in the band 17.3-17.8 GHz is in effect; b) that there is a requirement for identifying the need for coordination between fixed-satellite service (FSS) networks servin
5、g Regions 1 and/or 3, and BSS networks serving Region 2; c) that simple methods for identifying the need to coordinate between FSS and BSS networks would accelerate the coordination process, in fulfilment of the objectives of Resolution 86 of the Plenipotentiary Conference (Marrakesh, 2002); d) that
6、 typical network characteristics of BSS and FSS networks can be assumed for the RR establishment of a coordination arc to be applied between such networks; e) that, when a coordination arc applies for the determination of coordination requirements, administrations can request, under the provisions o
7、f RR No. 9.41, to be included in the coordination process for networks outside the established coordination arc defined in RR Appendix 5; f) that, in the cases referred to in considering e), administrations requesting to be included in the coordination process may need some information in order to h
8、elp them in conducting this coordination, noting a) that, per RR No. 5.517, starting from 1 April 2007 the FSS (space-to-Earth) in Region 2 in the band 17.7-17.8 GHz shall not cause harmful interference to, nor claim protection from, the BSS in this band, *This Recommendation should be brought to th
9、e attention of Working Party 6S. 2 Rec. ITU-R S.1780 recommends 1 that administrations, when conducting coordination under the provisions of RR No. 9.7, between assignments pertaining to a GSO BSS network serving Region 2 in the frequency band 17.3-17.8 GHz and assignments pertaining to a GSO FSS ne
10、twork serving Regions 1 and/or 3 in the same frequency band, take into consideration the material provided in Annex 1 in order to facilitate this coordination. Annex 1 Coordination between Region 2 GSO BSS networks (space-to-Earth) and GSO FSS networks (space-to-Earth) in the band 17.3-17.8 GHz Purs
11、uant to Resolution 901 (WRC-03), ITU-R reviewed the possible coordination arc value in the band 17.3-17.8 GHz. This band is totally or partially allocated, inter alia, to the BSS in Region 2 and to the FSS in the space-to-Earth direction. RR No. 5.516B applies with regard to the FSS downlink allocat
12、ion in Region 1. This Annex gathers the results of the studies conducted on the coordination of Region 2 GSO BSS networks with regard to FSS networks whose service areas are limited to Region 1 (reciprocal studies were also conducted within ITU-R and reached the same conclusion as in this Annex). Th
13、e results given in this Annex are a consequence of the natural geographical isolation between land masses of both Regions. The conclusions of this Annex may be extended to FSS networks in Region 3, taking into account the geographical isolation between Regions 2 and 3. 1 Methodology The methodology
14、to study the appropriate possible coordination arc value was derived from the method described in RR Appendix 8 as prescribed by RR Appendix 5 for requests for coordination under RR No. 9.7. The purpose of the study was: to assess the e.i.r.p. which could be radiated over Region 1 by a BSS network w
15、ithout triggering coordination with an FSS network depending on the orbital separation between the two networks; to compare the values found in the studies described in the above paragraph with technical parameters of BSS systems intended to be deployed in the band 17.3-17.8 GHz. 1.1 Derivation of m
16、aximum e.i.r.p. radiated without triggering coordination From the receiving system noise temperature and the interference criterion, an interference density was computed. The e.i.r.p. density towards a Region was then computed from this interference density taking into account only free space loss:
17、e.i.r.p.(density) = 10 log()tESdESgklttTRec. ITU-R S.1780 3 where: e.i.r.p.(density): e.i.r.p. density radiated by a satellite towards a Region (dB(W/Hz) TES: receiving earth station system noise temperature at antenna output (K) t/t: interference criterion k: Boltzmanns constant (1.38 1023J/K) ld:
18、downlink free space loss gES(t): receiving earth station antenna gain towards the interfering satellite t: topocentric angle between wanted and interfering satellites. The free-space loss was computed assuming a distance of 38 650 km and a frequency of 17.3 GHz. It was further assumed that the topoc
19、entric angle is 10% larger than the geocentric angle. No polarization advantage was taken into account. 2 Technical parameters of BSS and FSS networks 2.1 BSS networks This section presents BSS parameters (mainly maximum satellite e.i.r.p. and geographic separation) of systems intended to be deploye
20、d in the band 17.3-17.8 GHz. Thus a comparison can be drawn between these parameters and the ones found in 3, that will not trigger coordination between BSS and FSS networks. 2.1.1 Maximum satellite e.i.r.p. density Appendix 1 indicates that, for one system, the maximum satellite e.i.r.p. will be 57
21、.2 dBW/25 MHz (i.e. 16.8 dB(W/Hz) if an evenly spread power distribution is assumed) and, for the second one, the maximum satellite e.i.r.p. ranges from 64.2 dBW to 68.5 dBW (the associated channel bandwidths range from 25 MHz to 500 MHz). For this second network, it is not clear whether the higher
22、e.i.r.p. relates to the larger channel: in such a case, the e.i.r.p. densities vary from 9.8 dB(W/Hz) to 18.5 dB(W/Hz) if an evenly spread power distribution is assumed. Other studies within ITU-R included the following examples of BSS maximal e.i.r.p. values: for a general coverage beam, a peak e.i
23、.r.p. of 58 dBW/27 MHz (16.3 dB(W/Hz); for a spot beam, a maximum e.i.r.p. of 70 dBW/27 MHz (4.3 dB(W/Hz). 2.1.2 Geographical isolation Appendix 2 contains representative BSS satellite footprints (or envelopes). From these examples, it can be seen that the geographical isolation between Region 2 and
24、 Region 1 ranges from a little more than 10 dB to as much as 35 dB. For the purpose of this study, a parametric assessment was therefore made by using values of 10 dB, 15 dB and 20 dB as geographical isolation. 2.2 FSS networks 2.2.1 Interference criterion The criterion was derived from the section
25、of RR Appendix 5 dealing with RR No. 9.7 under which FSS systems in the band 17.3-17.8 GHz are coordinated: %6=TT4 Rec. ITU-R S.1780 2.2.2 Receiving earth station characteristics This section presents FSS receiving earth station characteristics which are representative of those planned to be deploye
26、d in adjacent bands (namely 17.7-20.2 GHz). The following was thus assumed: antenna diameter: 45, 60, 90 and 120 cm1; antenna radiation pattern: four antenna patterns were considered, namely Annex III of Appendix 8, Recommendation ITU-R S.465 (complemented by Appendix 8 for the main beam), Recommend
27、ation ITU-R S.580 (complemented by Appendix 8 for the main beam) and Recommendation ITU-R BO.1213; receiving system noise temperature at the output of FSS earth station antenna: 140 K. 3 Interference from GSO BSS networks into GSO FSS networks Section 2.1 presented some typical e.i.r.p. densities wh
28、ich would be radiated by BSS networks over Region 2. Table 1 summarizes the minimum orbital separation required to transmit a certain e.i.r.p. density without triggering coordination depending on FSS antenna patterns. 1Larger antennas may be used for gateways. Nevertheless, as the band is identified
29、 for HDFSS (see RR No. 5.516B), small antennas were primarily considered. Rec. ITU-R S.1780 5 TABLE 1 Orbital separation required for not triggering coordination with FSS networks Geographical isolation 10 dB 10 dB 10 dB 15 dB 15 dB 15 dB 20 dB 20 dB 20 dB BSS satellite e.i.r.p. over Region 2 5 dB(W
30、/Hz) 10 dB(W/Hz) 15 dB(W/Hz) 5 dB(W/Hz) 10 dB(W/Hz) 15 dB(W/Hz) 5 dB(W/Hz) 10 dB(W/Hz) 15 dB(W/Hz) RR Appendix 8 19.4 12.2 7.7 12.2 7.7 4.8 7.7 4.8 2.7 Recommendation ITU-R S.465 11.3 7.1 4.5 7.1 4.5 3.4 4.5 3.4 2.6 Recommendation ITU-R S.580 8.6 5.4 3.4 5.4 3.4 3.4 3.4 3.4 2.6 FSS antenna patterns
31、Recommendation ITU-R BO.1213 8.6 5.4 3.4 5.4 3.4 2.8 3.4 2.8 2.3 6 Rec. ITU-R S.1780 1.4 Conclusion This Annex shows that a coordination arc value of 8 would generally suffice to trigger coordination of BSS networks serving Region 2 with FSS networks serving Region 1. It should be noted that the sam
32、e geographical discrimination between Regions 2 and 3 as for between Regions 2 and 1 can be assumed. Therefore, the same conclusion can be extended to the case of coordination between BSS networks serving Region 2 and FSS networks serving Region 3. Appendix 1 to Annex 1 Examples of system parameters
33、 of unplanned BSS systems and associated feeder links in frequency bands 17.3-17.8 GHz and 24.75-25.25 GHz The following table contains a summary of representative coordination information for Region 2 BSS systems submitted to the Radiocommunication Bureau. These systems are considered representativ
34、e examples of the types of systems that can be expected to operate under the Region 2 BSS allocation. System characteristics System A System B Orbit GSO GSO Position 95.0 W 101.0 W Uplink 24.75-25.25 GHz 24.75-25.25 GHz Frequency Downlink 17.3-17.8 GHz 17.3-17.8 GHz Broadcast Coverage North America
35、North America Assigned channel bandwidth 25 MHz 25-500 MHz Uplink Satellite receive antenna gain 35 dBi 49.4 dBi Earth station transmit antenna size 5.6 m, 3.5 m 5-13 m Earth station transmit antenna gain (maximum) 61.1 dBi, 57.0 dBi 60.5-68.8 dBi Receiving satellite system noise temperature 730 K 8
36、10 K Earth station transmit antenna pattern RR AP 4 A, B, C, D, parameters: 29, 25, 32, 25, 7 Rec. ITU-R S.465 Polarization Circular left Circular left Maximum power supplied to the input of Earth station transmitting antenna 22.2 dBW 21.2-29.5 dBW Downlink Satellite transmit antenna gain 35 dBi 49.
37、4 dBi Earth station receive antenna size 0.45-1.4 m 0.45-1.2 m Earth station receive antenna gain 36.1-46.0 dBi 36.5-45.0 dBi Rec. ITU-R S.1780 7 System A System B Polarization Circular right Circular right Earth station receive noise temperature 170 K 140 K Earth station receive antenna pattern See
38、 detailed pattern following this table Rec. ITU-R S.465 Maximum power supplied to the input of satellite transmitting antenna 22.2 dBW 14.8-19.1 dBW Eb/N06.5 dB No Information C/N threshold 6.6 dB No Information Required C/N (clear-sky) 9.0 dB Uplink 17.4 dB, Downlink 6-17.6 dB System A only Forward
39、 link Coverage Visible Earth Channel bandwidth 25 MHz Uplink Satellite receive antenna gain 44.5 dBi Earth station transmit antenna size 5.6 m, 3.5 m Earth station transmit antenna gain (maximum) 61.1 dBi, 57.0 dBi Receiving satellite system noise temperature 730 K Earth station transmit antenna pat
40、tern RR AP 4 A, B, C, D, parameters: 29, 25, 32, 25, 7 Polarization Circular left Maximum power supplied to the input of Earth station transmitting antenna 18.0 dBW Downlink Satellite transmit antenna gain 44.5 dBi Earth station receive antenna size 0.45-1.4 m Earth station receive antenna gain 36.1
41、-46.0 dBi Polarization Circular right Earth station receive noise temperature 170 K Earth station receive antenna pattern See detailed pattern following this table Maximum power supplied to the input of satellite transmitting antenna 21.0 dBW Eb/N06.5 dB C/N threshold 6.6 dB Required C/N (clear-sky)
42、 11.0 dB Return link Coverage Visible Earth Channel bandwidth 55 MHz, 113 MHz Uplink Satellite receive antenna gain 44.5 dBi 8 Rec. ITU-R S.1780 System A System B Earth station transmit antenna size 0.45-1.4 m Earth station transmit antenna gain (maximum) 39.2-49.1 dBi Receiving satellite system noi
43、se temperature 730 K Earth station transmit antenna pattern Rec. ITU-R S.465 Uplink polarization Circular left, circular right Maximum power supplied to the input of Earth station transmitting antenna 36.4 dBW, 39.7 MHz Downlink Satellite transmit antenna gain 44.5 dBi Earth station receive antenna
44、size 5.6 m, 3.5 m Earth station receive antenna gain 58.0 dBi, 54 dBi Downlink polarization Circular right, circular left Earth station receive noise temperature 185 K Earth station receive antenna pattern RR AP 4 A, B, C, D, parameters: 29, 25, 32, 25, 7 Maximum power supplied to the input of satel
45、lite transmitting antenna 21.2 dBW Eb/N06.5 dB C/N threshold 6.6 dB Required C/N (clear-sky) 10.0 dB System A earth station receive antenna pattern Earth station receiving antenna pattern: Gco() = Gmax 2.5 1032Dfor 0 mwhere m= 0025.01GGDmaxGco() = G1= 29 25 log10rfor m rwhere r= 95 DGco() = 29-25 lo
46、g10 for r 7 Gco() = 7.9 dBi for 7 9.2 Gco() = 32-25 log10 for 9.2 48 Gco() = 10 dBi for 48 180 where: Gco:co-polar gain (dBi) Gmax: maximum isotropic gain of the antenna (dBi) : off-axis angle (degrees) D: antenna diameter (m) : wavelength (m). Rec. ITU-R S.1780 9 Appendix 2 to Annex 1 Examples of BSS satellite antenna patterns 10 Rec. ITU-R S.1780
