1、 Rec. ITU-R SA.1277-0 1 RECOMMENDATION ITU-R SA.1277-0*, * SHARING IN THE 8 025-8 400 MHz FREQUENCY BAND BETWEEN THE EARTH EXPLORATION-SATELLITE SERVICE AND THE FIXED, FIXED-SATELLITE, METEOROLOGICAL-SATELLITE AND MOBILE SERVICES IN REGIONS 1, 2 AND 3 (Question ITU-R 214/7) (1997) Rec. ITU-R SA.1277
2、 The ITU Radiocommunication Assembly, considering a) that fixed services (FS), fixed-satellite services (FSS) and mobile services are allocated on a primary basis in the 8 025-8 400 MHz frequency band in the three Regions; b) that the meteorological-satellite (METSAT) service is allocated on a prima
3、ry basis in the 8 175-8 215 MHz frequency band in the three Regions; c) that the Earth exploration-satellite service (EESS) is allocated on a primary basis in Region 2, and on a secondary basis in Regions 1 and 3 in the 8 025-8 400 MHz frequency band; d) that no interference can be caused by the EES
4、S to the FS and the mobile service when the power flux-density (pfd) limits imposed by the Radio Regulations (RR) No. S21.16 are respected (see 1 of Annex 1); e) that no interference can be caused by the EESS to the FSS and the METSAT when the pfd limits at the geostationary orbit, imposed by the RR
5、 No. S22.5, are respected (see 2 of Annex 1); f) that the study in 2 of Annex 2 shows that there exists extensive possibilities for siting of EESS earth stations among a network of fixed stations; g) that considering f) may be extended also for siting EESS earth stations with respect to fixed-satell
6、ite and meteorological earth stations (see 3 of Annex 2); h) that the study in 4 of Annex 2 shows that, as in considering f), there exists extensive possibilities for siting of EESS earth stations among mobile stations; j) that from the experience gained over the last 20 years, it is demonstrated th
7、at no frequency sharing problems can be encountered between the EESS and the FS, the FSS, the METSAT and mobile services in the three Regions; k) that the effective planning and development of future EESS networks with global coverage require a primary allocation status in the three Regions, recomme
8、nds 1 that sharing between the EESS and the FS, the FSS, the METSAT and the mobile services in the 8 025-8 400 MHz band is feasible subject to the following conditions: RR No. S22.5 and RR No. S21.16 provisions apply; the method described in Annex 2 be used to calculate separation distances between
9、earth stations of the EESS and terrestrial stations or earth stations of the other services. (Separation distance refers to the distance that could be achieved in coordination). _ * This Recommendation should be brought to the attention of Radiocommunication Study Groups 4, 8 and 9. * Radiocommunica
10、tion Study Group 7 made editorial amendments to this Recommendation in the year 2017 in accordance with Resolution ITU-R 1. 2 Rec. ITU-R SA.1277-0 ANNEX 1 Analysis of interference from the EESS to other services in the frequency band 8 025-8 400 MHz 1 Interference potentiality from space stations of
11、 the EESS to terrestrial stations of the FS and the mobile service The RR No. S21.16 imposes pfd limits at the ground level relative to the space stations emissions. These limits are given in Table 1 for the 8 025-8 400 MHz frequency band in 4 kHz bandwidth. TABLE 1 pfd limits in the 8 025-8 400 MHz
12、 frequency band In so far as the transmitters of the Earth exploration-satellite stations respect these constraints, the FS and mobile service receivers are protected because these limits have been set so as to avoid the interferences from space stations transmitters to terrestrial services. 2 Inter
13、ference from space stations of the EESS to space stations of the FSS and the METSAT service The relative position of the near-polar circular orbit of an EESS satellite and the GSO is shown in Fig. 1. The EESS satellite directs its maximum e.i.r.p. to the horizon of its coverage. The worst case occur
14、s when this satellite, the horizon of its coverage and a geostationary satellite (FS or meteorological service) are in alignment as shown in Fig. 2. According to RR No. S22.5 the pfd at the GSO shall not exceed 174 dB(W/m2) in any 4 kHz bandwidth. With typical EESS satellite characteristics, as give
15、n in Table 2, the actual pfd produced at GSO in the worst case is 183 dB(W/m2) in 4 kHz. The effect of such pfd on the FSS and on the METSAT service is illustrated here below. To estimate the worst-case interference from the EESS satellite to the geostationary-satellite receiver we can express the r
16、atio between the received powers at the input of this receiver, from the earth stations transmitting to the geostationary satellite and the EESS satellite respectively: C/I (Ptw Gtw) (Ptu Gtu) Lp 10 log (Bu/Bw) where: Ptw : transmitter power of the earth station (dBW) Gtw : antenna gain of the earth
17、 station (dBi) Ptu : transmitter power of the EESS satellite (dBW) Gtu : antenna gain of the EESS satellite to the horizon of its coverage (dBi) Lp : differential path loss between the desired and undesired signals (dB) Bu : emission bandwidth of the unwanted signal (Hz) Bw : emission bandwidth of t
18、he desired signal (Hz). Arrival angle, pfd limit (dB(W/(m2.4 kHz) 0 5 150 5 25 150 ( 5) / 2 25 90 140 Rec. ITU-R SA.1277-0 3 1 2 7 7 - 0 1F I G U R E 1R e l a t i v e p o s i t i o n s o f t h e G S O a n d t h e n e a r - p o l a r o r b i to f a n E E S S s a t e l l i t e ( 1 0 0 r e t r o g r a
19、d e )G S OE E S S s a t e l l i t e o r b i tE q u a t o rFIGURE 1/SA.1277.D01 = 3 CM 1 2 7 7 - 0 23 5 7 8 6 k m6 3 7 8 k mF I G U R E 2R e p r e s e n t a t i o n o f t h e w o r s t c a s e o f i n t e r f e r e n c e f r o m a n E E S S s a t e l l i t et o a F S o r a M E T S A T s e r v i c eG
20、e o s t a t i o n a r y s a t e l l i t eE E S S s a t e l l i t e6 0 0 k mFIGURE 2/SA.1277.D02 = 3 CM In this formula it is assumed that the emission bandwidth of the unwanted signal is greater than or equal to the emission bandwidth of the desired signal and that the spectrum of the unwanted signa
21、l completely recovers the desired signal one. Then we can replace the previous formula by the formula below: C/I ptw Gtw (ptu Gtu) Lp where: ptw : average transmitter power density of the desired signal (dB/Hz) ptu : average transmitter power density of the undesired signal in the band of the desire
22、d signal (dB/Hz). We can evaluate the term Lp for a worst case with an EESS satellite orbit altitude of 600 km and an earth station located at the nadir of the geostationary satellite: Lp 20 log 35 786 6 378 6 378 6 378 600 6 37835 7862 2 2 2 namely: Lp 1.9 dB 4 Rec. ITU-R SA.1277-0 Table 2 gives th
23、e technical characteristics of the EESS satellites SPOT 1/2/3/4. The spectral power density is the maximal density (i.e. at the centre of the QPSK signal) that represents the worst case of the interference. TABLE 2 Main characteristics of the EESS satellites SPOT 1/2/3/4 Table 3 gives the technical
24、characteristics of the earth stations transmitting to a governmental telecommunication satellite in the 8 025-8 400 MHz frequency band, as well the C/I ratios obtained for the telecommunication satellite with the characteristics of the EESS satellite given in Table 2. TABLE 3 Main technical characte
25、ristics of earth stations transmitting to a governmental telecommunication satellite in the 8 025-8 400 MHz frequency band and C/I ratios obtained for thetelecom munication satellite with the characteristics of the EESS satellite given in Table 2 Table 4 gives the main technical characteristics of t
26、he METSAT earth stations and the C/I ratios obtained for the meteorological satellite with the characteristics of the EESS satellite given in Table 2. TABLE 4 Characteristics of a METSAT earth station and C/I ratios obtained for the meteorological satellite with the characteristics of the EESS satel
27、lite given in Table 2 Modulation Bit rate (Mbit/s) Power (dBW) Maximal spectral power density (dB(W/Hz) Maximal gain (dB) QPSK 50 12.5 61.5 6.2 Earth station category Antenna diameter (m) Maximum antenna gain (dBi) Maximum power density (dB(W/Hz)(1) Bandwidth (MHz) C/I (dB) G 18 61 43.5 60 74.7 H 8
28、54 34 60 77.2 I 3 44.5 44 40 57.7 J 1.5 39.5 44 40 52.7 K 1.3 38.5 38 40 57.7 L 0.9 35 38.8 80 53.2 L 0.9 34.5 38.8 80 52.9 (1) In the worst case 4 kHz band. Antenna gain (dBi) Maximum transmitter power (dB) e.i.r.p. (dBW) Bandwidth (MHz) power density (dB(W/Hz) C/I (dB) 44 30 74 0.960 29.6 71.6 44
29、20 64 0.018 22.6 78.6 44 13 57 0.0024 20.8 80.4 44 17 61 0.0004 9.0 92.2 Rec. ITU-R SA.1277-0 5 We conclude that there would not be interference from the EESS space stations with characteristics similar to those ones given in Table 2 to the fixed-satellite or METSAT receivers. ANNEX 2 Analysis of in
30、terference to the EESS from other services in the frequency band 8 025-8 400 MHz Method for calculating separation distances between earth stations of the EESS and terrestrial stations or earth stations of the other services 1 Introduction This Annex concerns the a priori evaluation of the order of
31、magnitude for acceptable separation distances between an EESS earth station on one hand and a fixed, fixed-satellite, METSAT or mobile station on the other hand, as a function of given parameters. It is precised that the following calculation does not replace the method given in Appendix S7 of the R
32、R and it is not intended to use it for evaluation of coordination distances. The calculation of the attenuation over the interference path is not based on the worst case but on an average case, which only refers to diffraction caused by an obstacle located between the two stations. The separation di
33、stances calculated here gives a realistic idea of practical sharing possibilities between EESS and FS, FSS, METSAT or mobile services. 2 Interference from terrestrial fixed service transmitters to EESS earth station receivers The sharing criterion for this interference path is a coordination distanc
34、e required to ensure adequate separation between the terrestrial service transmitters and the EESS earth station receivers. The minimum permissible basic transmission loss to protect the earth station can be stated as: Lb( p%) Pt Gt (t) (Pi Gr (r) where: Pt : terrestrial service transmitter power (d
35、BW) Gt (t) : terrestrial service antenna gain in the direction of the earth station (dBi) Gr (r): gain of the earth station antenna in the direction of the terrestrial station (dBi) Pi : maximum permissible interference at the earth station receiver input (dBW) t : angle between the terrestrial serv
36、ice antenna axis and the interference path (degrees) r : angle between the EESS antenna axis and the interference path (degrees) Lb( p%): the value of minimum acceptable basic transmission loss to be exceeded for all but p% of the time along the interference path between the terrestrial transmitter
37、and the earth station receiver (dB). The values of Pi and p are defined by Recommendation ITU-R SA.1027 and given in Table 5 for the 8 025-8 400 MHz frequency band. 6 Rec. ITU-R SA.1277-0 TABLE 5 Sharing criteria for space-to-Earth data transmission systems operating in the EESS using satellites in
38、low-Earth orbit, according to Recommendation ITU-R SA.1027 The values of gain Gr (r) for the worst case, i.e. when the earth station antenna is plotted in azimuth to the undesired signal and at 5 of elevation can be obtained from the formulas below given in the Appendix S7 of the RR: for D/ 100: Gr(
39、r) 32 25 log r for n r 48Gr(r) 10 dBi for 48 r 180 for D/ 100: Gr(r) = Gmax 2.5 10-3( )2 for 0 r m Gr(r) = G1 for m r 100 /D Gr(r) = 52 10 log(D/) 25 log r for 100 /D r 48o Gr(r) = 10 10 log(D/) for 48o r 180o where: nm m a xDD G GG D1 5 .8 5 ( /( /)/ l o g )0 .611202 15The value r is given by: r 5
40、r where: r : the elevation of the earth stations physical horizon in the direction of the terrestrial station. The values of Gr(r) for a 55.2 dBic antenna (for recorded data acquisition) and for a 36.4 dBic antenna (for direct data readout) are given in Tables 6 and 7. EESS earth station category Re
41、ference bandwidth (MHz) Interfering signal power to be exceeded for no more than 20% of the time at elevation angles 5(dBW) Interfering signal power to be exceeded for no more than p% of the time at elevation angles 5(dBW) 55.2 dBic antenna, for recorded data acquisition 100 130 117 p 0.010 36.4 dBi
42、c antenna, for direct data readout 40 134 126 p 0.011 Rec. ITU-R SA.1277-0 7 TABLE 6 Earth station receiving antenna gains (55.2 dBic,* for recorded data acquisition) pointed in azimuth to the undesired signal and at 5 elevation towards the undesired signal TABLE 7 Earth station receiving antenna ga
43、ins (36.4 dBic, for direct data readout) pointed in azimuth to the undesired signal land at 5 elevation towards the undesired signal Table 9 gives the minimum permissible basic transmission losses along the interference path evaluated from the data given in Table 5 corresponding to p 0.025% of the t
44、ime and the radio-relay system characteristics given in Table 8, for various offset angles between the radio-relay antenna axis and the direction of the EESS Earth station antenna and for the horizon elevation angles 0.5 and 3 (see Fig. 3). TABLE 8 Characteristics of a radio-relay transmitter Elevat
45、ion angle, r (degrees) Minimum separation angle between the antenna axis and the arrival direction, r 5 r (degrees) Maximum gain for an antenna plotted at 5 elevation angle 5 (dBi) 0.5 4.5 15.7 1 4 16.9 2 3 20.1 3 2 24.5 4 1 32.0 * dBic refers to the gain of an isotropic antenna with circular polari
46、zation. Elevation angle, r (degrees) Minimum separation angle between the antenna axis and the arrival direction r 5 r (degrees) Maximum gain for an antenna plotted at 5 elevation angle (dBi) 0.5 4.5 21.3 1 4 22.6 2 3 23.6 3 2 28.6 4 1 34.2 Power transmitted per channel (dBW) 0 to 2 Channel bandwidt
47、h (MHz) 25 Number of channels in 100 MHz 3 Pt1 Power transmitted in 100 MHz (dBW) 5 to 7 Number of channels in 40 MHz 2 Pt2 Power transmitted in 40 MHz (dBW) 3 to 5 Gt (0) Antenna gain in the axis (dBi) 43 Gt (10) Antenna gain at 10 of the axis (dBi) 11 Gt (45) Antenna gain at 45 of the axis (dBi) 2
48、 Gt (90) Antenna gain at 90 of the axis (dBi) 2 8 Rec. ITU-R SA.1277-0 TABLE 9 Minimum permissible basic transmission losses (dB) along the interference path to protect the EESS Earth station from the emissions of the radio-relay transmitter described in Table 8 1 2 7 7 - 0 3rrtE E S S E a r t h s t a t i o nF i x e d o r m o b i l e s e r v i c e s t a t i o n F i x e d o r m o b i l e s e r v i c e s t a t i o nF I G U R E 3R e p r e s e n t a t i o n o f i n t e r f e r e n c e f r o m a F S o r m o b i l es e r v i c e s t a t i o n t o a n E E S S E a
