1、 STD-ITU-R RECMN S.1327-ENGL 1997 m 4855212 0530448 443 m Rec. ITU-R S.1327 1 RECOMMENDATION ITU-R S.1327 REQUIREMENTS AND SUITABLE BANDS FOR OPERATION OF THE INTER-SATELLITE SERVICE WITHIN THE RANGE 50.2-71 GHZ (Question ITU-R 246/4) (1 997) The ITU Radiocommunication Assembly, considering a) that
2、Resolution 643 of the World Radiocommunication Conference (Geneva, 1995) (WRC-95) instructs the ITU-R to carry out the necessary studies to identi the bands most suitable for the inter-satellite service (ISS) in order to enable the World Radiocommunication Conference (Geneva, 1997) (WRC-97) to make
3、appropriate allocations to that service; b) that the technical and operational requirements of the ISS in the frequency range 50.2-71 GHz are identified in Annex 2 of this Recommendation; c) that the networks identified in Annex 2 typically require wide bandwidths, and typically form high data rate
4、trunk links for the space segments of networks; d) e) exploration-satellite service (EESS) (passive) in this range; f) the range 65-71 GHz; g) improve sharing conditions with terrestrial stations of other services; h) feasible (see Annex 3), that there is extensive planned use of the ISS in the rang
5、e 50.2-71 GHz; that there is a potential for unacceptable interference from large numbers of inter-satellite links into the Earth that there are no known existing or currently planned terrestrial or space systems in the current allocations in that the absorption characteristics of the atmosphere to
6、radio waves, within the range under consideration, may that studies have confirmed that sharing between the ISS and terrestrial services in the band 66-71 GHz is I recommends 1 - that the bands most suitable for the ISS in the range 50.2-71 GHz include: 54.25-58.2 GHz, limited to networks employing
7、geostationary-satellite orbit (GSO) satellites in accordance with Recommendation ITU-R S.Doc. 4/1005; - 59-64GHz; - 65-71 GHz, 2 that the allocations to the ISS in this frequency range be contiguous bands of sufficient width to accommodate the unique needs of the ISS. NOTE 1 - Recommendations ITU-R
8、S.Doc. 4/1005 and ITU-R 7C/43 address feasibility of sharing between the ISS and spaceborne passive sensors in the frequency range 50-65 GHz. NOTE 2 - Recommendation ITU-R S. 1326 addresses sharing between the fixed-satellite service (FSS) and the ISS in the NOTE 3 -Annex 1 to this Recommendation su
9、mmarizes the sharing potential of the ISS with other services in the frequency range 50.2-11 GHz. band 50.4-5 1.4 GHz. ANNEX 1 This Annex summarizes potential for the ISS sharing with the following services: a) Fixed service in the bands 50.2-51.4, 54.25-58.2 and 59-64 GHz - STD-ITU-R RECMN S-1327-E
10、NGL 1797 W 4855212 0530449 38T m 2 Rec. ITU-R S.1327 Sharing is feasible in these bands. However, the band 50.2-51.4 GHz may not be of sufficient bandwidth to accommodate ISS requirements. STD-ITU-R RECMN S.1327-ENGL 1777 4855212 0530450 OT1 3 Rec. ITU-R S.1327 b) FSS in the band 50.4-5 1.4 GHz Stud
11、ies have shown that sharing between GSO ISS and GSO FSS in this band would be feasible with certain mitigation techniques. However, sharing between other systems, such as GSO and non-GSO FSS sharing with non-GSO ISS may be difficult and requires further study (see Recommendation IT-R S. 1326). c) St
12、udies have shown that oxygen absorption, as well as antenna discrimination, will attenuate signals to an extent which will allow sharing with these systems. d) EESS (passive) and space research service (SRS) (passive) in the bands 50.2-50.4 GHz, 5 1.4-59 GHz, 59-64 GHz, and 64-65 GHz Mobile service
13、in the bands 50.2-5 1.4,54.25-58.2,59-64 and 66-71 GHz Studies have shown that there is potential for unacceptable interference from non-GSO systems utilizing the ISS in these bands. Sharing between GSO ISS or Hybrid ISS and EESS (passive) is feasible, and sharing conditions are given in Recommendat
14、ion ITU-R S.Doc. 4/1005. In the band 59-64 GHz, existing non-GSO ISS systems could also cause harmful interference and possibly even damage to EESS (passive) sensors. It is recommended that passive sensors be made aware of the potential for interference from existing systems. It is also noted that t
15、here are no requirements for the EESS (passive) or SRS (passive) in the band 64-65 GHz, therefore, this band may be suitable for non-GSO ISS. However, this band is also allocated by footnote to the radio astronomy service (RAS), and no sharing studies have been carried out on the feasibility of the
16、ISS to share with the RAS. e) Studies have shown that oxygen absorption, as well as antenna discrimination will attenuate signals to an extent which could allow sharing between these systems. Information is required on the RNS service to enable firm conclusions to be drawn. f) Studies have shown tha
17、t an interference potential would exist from the ISS into MSS spacebome receivers for systems with similar orbital heights. However, sharing at similar orbital heights may also be possible if use is made of polarization discrimination. other potential interference situations exist as the MSS has a b
18、idirectional allocation. Interference between these systems requires further study. g) Studies have shown that an interference potential would exist from the ISS into RNSS spacebome receivers for systems with similar orbital heights. However, sharing at similar orbital heights may also be possible i
19、f use is made of polarization discrimination. Other potential interference situations exist as the RNSS has a bidirectional allocation. Interference between these systems requires further study. h) Radionavigation service (RNS) in the band 66-7 1 GHz Mobile-satellite service (MSS) in the bands 66-7
20、1 GHz Radionavigation-satellite service (RNSS) in the band 66-71 GHz SRS and the EESS in the band 65-66 GHz This band will not be used for spacebome passive sensing; it is intended to be used for the transmission of data in the space-to-Earth direction. Liaison within the ITU-R revealed that there a
21、re no current plans for EESS or SRS systems in the band. Sharing between satellite networks in the EESS (space-to-Earth) and SRS (space-to-Earth), and those of the ISS is not expected to be difficult. ANNEX 2 Characteristics and requirements of systems planning to use the ISS near 60 GHz 1 This Anne
22、x identifies systems operating, or planning to operate, in the ISS near 60 GHz. A distinguishing characteristic of these systems is the requirement for large bandwidths. ISS users typically form high data rate trunk links for the space segments of networks. A typical user of the networks might be a
23、user of the FSS, or the MSS. STD-ITU-R RECMN S.1327-ENGL 1977 m 4855232 0530Li5L 738 m 4 Rec. ITU-R S.1327 The typical user might be serviced by a 2.4 kbit/s voice link, or a 1.544 Mbit/s data link, and there might be as many as 250 O00 end voice users on a single 1 Gbit/s inter-satellite link (ISL)
24、. 2 Estimated bandwidth requirements for ISS for systems near 60 GHz In order to estimate the bandwidth required for operation of the GSO ISS, a survey of existing and planned GSO ISS systems was conducted. As of end-1996 there are ten GSO ISS systems planned for operation near 60 GHz, with 74 satel
25、lites and up to 178 GSO ISLs. Many of the planned GSO locations are crowded over regions of Europe and the United States of America. There are four proposed non-GSO ISS systems, with close to 1 O00 satellites and nearly 8 O00 links. Most of these systems are low-Earth orbiting systems. 2.1 Short ISL
26、s (short links) Short ISLs (system angle of 10“ or less) are estimated to require up to 10“ of orbital separation from co-frequency GSO ISS systems. Each node in a short link requires up to 2 GHz of bandwidth. With 10 of orbital separation required between each Co-frequency short link, and 2“ of orb
27、ital separation between any two GSO satellites, a factor of 5 is estimated to provide adequate spectrum for GSO ISS short links, for a total of 10 GHz. 2.2 Long ISLs (long links) For long inter-satellite links (orbital separation greater than lo“), 2 of orbital separation between co-frequency GSO IS
28、S systems is enough to achieve the performance criterion of CII 2 30 dB. Under these conditions, 4 GHz of spectrum is sufficient for frequency re-use, since at least one GSO ISS system is designed for a minimum of 4 GHz. However, there is no guarantee that 2“ orbital separations can be maintained, e
29、specially in the crowded areas of the geostationary arc. A separation of 1 between systems would imply that twice as much spectrum is needed, as much as 8 GHz. 2.3 Growth The above analysis does not account for the growth of GSO ISS systems. A growth factor of 1.5 can be used to estimate potential g
30、rowth of the ISS in the near future (1 0-20 years). Applying the growth factor yields an estimated requirement of 15 GHz for short links, or 12 GHz for long link GSO ISS systems. 2.4 Estimated bandwidth requirements for non-GSO ISS for systems near 60 GHz The total bandwidth estimated for the propos
31、ed non-GSO systems is 8.2 GHz. Allowing for a growth factor of 1.5, the estimated requirement for non-GSO systems is near 12 GHz. 2.5 Summary Due to the orbital separations required between GSO ISS systems with short inter-satellite links, and to overcrowded conditions in certain regions of the geos
32、tationary arc, the estimated requirement for full use of planned and future GSO ISS systems is 15 GHz. For non-GSO systems, about 12 GHz is the estimate. 3 Additional work to be done These data rates can be associated with the hypothetical digital reference path (HDRP) standards, to allow meaningful
33、 sensitivity to interference to be defined. STD-ITU-R RECMN S.1327-ENGL 1997 W 4855232 0530452 774 = Peak power (dBW) Peak e.i.r.p. (dBW) Rec. ITU-R S.1327 16 71.3 75 5 63.3 TABLE 1 GSO system characteristics 62.1 68.7 75 55.7 53.5 Antenna gain (dBi) Antenna diameter (m) 58.5 60.3 1.8 2 System noise
34、 temperature (K) Rx GIT (dB(K-) 468.4 800 Non-GSO systems LEOSAT 1 w-2c W-2d w-9 No. of planes No. of satellites per plane Period (average) (min) 21 10 12 12 44 1 1 6 98.77 718.03 I 05 113 Inclination (average) (degrees) Ascending node spacing (degrees) 98.16 63.4 55-1 10 47 9.5 Various Various 30 E
35、ccentricity 0.72 various 0.0013 No. of Tx/Rx pairs per satellite Total bandwidth required (GHz) Peak power (dBW) Peak e.i.r.p. (dBW) Bandwidth of each beam (GHz) 8 2 2 4 1 3.2 3.2 1.5 2 3.2 3.2 3 7.4 16 16 4 55.4 75 75 59.9 Antenna gain (dBi) Antenna diameter (m) System noise temperature (K) Maximum
36、 geocentric separation angle (degrees) 48 60.3 60.3 55.9 0.5 2 2 1.2 438 800 800 501 30 19 - - W-2b () No. of satellites 131 4 15 2 No. of Tx/Rx Daifs oer satellite I 2 I 2 Bandwidth (GHz) I 1 I 3.2 0.04 I I 3.2 Total bandwidth required (GH4 0.08 1 1.76 * 13 I 13 I 13 I 21 -1 57 46t55.5 I 6:; 1 0.41
37、1.2 58 2 034 24.9 23.4 I 23.4 I 27.4 I 24.5 I 19128.5 19.8125.9 I 145 I 163 Largest longitudinal separation angle (degrees) I 63 (1 Any of the W-2 system nodes can communicate with other W-2 nodes TABLE 2 Non-GSO system characteristics STD-ITU-R RECMN S-3327-ENGL 3777 m 4855232 0530453 800 rn Rec. I
38、TU-R S.1327 7 ANNEX 3 Assessment of potential allocation of the ISS in the 66-71 GHz band 1 Introduction The ISS has a CO-primary allocation in the 54.25-58.2 GHz band which is used by the EESS for passive sensing. Microwave sensors on board operational spacecraft can provide environmental and clima
39、tic data which are increasingly important for monitoring the temperature of the Earths atmosphere. he atmospheric temperature profiles are of fundamental importance for initialization of numerical weather prediction models, and for retrieval of other important scientific data. The global user commun
40、ity, including the World Meteorological Organization, the Global Climate Observing System and the World Climate Research Programme, have defmed satellite dah requirements for atmospheric parameters including temperature and water vapour profiles, ozone concentration, and other radiative and chemical
41、ly active trace gases, which can only be met by satellite passive sensors. Oxygen absorption lines in the 50.2-66 GHz region are unique natural resources used for all-weather passive microwave remote sensing of the atmosphere. An alternative is not available in other frequency bands. The fiequency b
42、and 54.25-58.2 GHz is shared between EESS (passive), fmed, mobile and ISSs. It has been concluded in earlier studies that inter-satellite systems with a significant number of Iow-Earth orbiting satellites can produce unacceptable levels of interference to passive microwave sensors. The Space Frequen
43、cy Coordination Group (SFCG) has resolved that it would be very desirable to make the relevant fiequency band exclusive for passive services and to re-allocate the ISS in the fiequency range 66-71 GHz, except for the 56.9 to 57 GHz band, to ensure the ability to make atmospheric temperature measurem
44、ents and to avoid a need for constraints on the parameters for active services. The 66-71 GHz band provides 5 GHz of bandwidth compared to 3.95 GHz in the 54.25-582 GHz band and should thus be an attractive alternative to the current allocation. This study concentrates on the sharing assessment betw
45、een ISS and ail primary services allocated in the 66-7 1 GHz band. 2 ISS system characteristics It is difficult to make general predictions on characteristics for ISS systems which would use frequencies above 50 GHz. There is, however, one system already in an advanced planning stage which can be us
46、ed as a representative case for a sharing assessment. The proposed non-GSO type system is referred to as LEOSAT-1 and consists of 924 low-Earth orbiting satellites (840 active satellites and 84 spares) which are planned to provide basic voice services, multimedia conferencing, tele-medicine, distanc
47、e learning and video telephony on a global basis. The inter-satellite links are designed in such a way that each satellite is connected to the closest four satellites in the same orbit plane and to two others each in the two adjacent planes. Transmissions are planned to be effected at 56 and 59 GHz,
48、 left-hand circular and right-hand circular, in order to reduce mutual intederence. Typical technical characteristics of a potential future system, for which Appendix 3 to the Radio Regulations information was submitted to the IT in 1995 are given in Table 3. Each satellite is connected to eight oth
49、er satellites so that eight transmissions per satellite have to be considered in total. The links between the various satellites are shown in Fig. 1. For the purpose of this study, it is assumed that the 56 GHz transmissions can be moved to frequencies around 66 GHz and the 59 GHz transmissions to 70 GHz. Regarding atmospheric attenuation, the 70 GHz case is the more critical one because attenuation due to dry air is significantly higher at 66 GHz and results consequently in lower interference signal levels at the Earths surface. In order to
