Recommendation itu-r s. 1433 uplink and inter-satellite equivalent power flux-density radiated by non-gso fss systems




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Rec. ITU-R S.1433

RECOMMENDATION ITU-R S.1433

UPLINK AND INTER-SATELLITE EQUIVALENT POWER FLUX-DENSITY
RADIATED BY NON-GSO FSS SYSTEMS

(2000)

Rec. ITU-R S.1433
The ITU Radiocommunication Assembly,

considering

a) the limits on the power flux-density (pfd) received at the GSO from Earth-to-space or space-to-Earth transmission within non-GSO FSS networks in the frequency band covered by Resolution 130 (WRC-97) should provide protection for GSO FSS networks;

b) that such limits should be established taking into account the geostationary satellite receiving antenna characteristics;

c) that these limits should take account of all the earth stations or space stations, as appropriate, of a non GSO FSS network within visibility of the geostationary satellite;

d) that the discriminating characteristics of the geostationary satellite antenna should be included in the definition of the limit;

e) that such limits to the uplink equivalent power flux-density (epfdup) should apply in FSS (Earth-to-space) allocations at 12.5 13.25 GHz, 13.75 14.5 GHz, 27.5-28.6 GHz and 29.5-30.0 GHz in accordance with Resolution 130 (WRC-97);

f) that such limits to the inter-satellite equivalent power flux-density (epfdis) should apply in FSS (space-to-Earth) allocations used by non-GSO FSS which are shared with GSO FSS Earth-to-space in the bands 10.7 11.7 GHz, 12.5 12.75 GHz and 17.8-18.4 GHz;

g) that designers of non-GSO FSS systems need a definition of the limits of their transmissions at the GSO arc;

h) that the operators of GSO FSS satellites will accept interference from non-geostationary co channel systems when they meet certain epfdup or epfdis limits,

recommends

1 that when considering the design of non-GSO FSS systems the definition for epfdup or epfdis should be used as indicated in Annex 1;

2 that when determining epfdup or epfdis radiated by their systems, non-GSO system designers should consider that the normalized GSO FSS space station receive antenna pattern is:

2.1 for the frequency bands 10.7-11.7 GHz, 12.5-13.25 GHz, 13.75-14.5 GHz and 17.8 18.4 GHz: Recommendation ITU-R S.672 with a gain of 32.4 dBi, a side-lobe level of –20 dB, and a half-power beamwidth of 4º;

2.2 for the frequency bands 27.5-28.6 GHz and 29.5-30.0 GHz: Recommendation ITU-R S.672 with a gain of 40.7 dBi, a side-lobe level of –10 dB, and a half-power beamwidth of 1.55°;

3 that the epfdup and epfdis limits indicated in Annex 2 should not be exceeded by non-GSO FSS systems using the allocations indicated in considering e) and f) above and are considered by GSO FSS systems as meeting the requirements of Article S22 of the RR;

4 that in designing GSO FSS networks, administrations should take into account interference from non-GSO FSS systems produced at the levels in Annex 2 so that this interference is acceptable.

ANNEX 1


Common definition of epfdup and epfdis

The epfdup is defined as the weighed sum of the pfd produced at the geostationary orbit by all the transmit earth stations within a non geostationary-satellite system. epfdis is defined as the weighed sum of the pfd produced at transmit space station within a non-GSO system. In both definitions the off-axis discrimination of a reference receiving antenna assumed to be pointing in its nominal direction is taken into account. The epfd is calculated using the following formula:



where:


epfd : computed equivalent power flux-density (dB(W/m2)) in the reference bandwidth

Na : number of transmit stations in the non-geostationary-satellite system that are visible from the GSO receive space station, considered on the Earth's surface or in the geostationary orbit, as appropriate

i : index of the transmit station considered in the non geostationary-satellite system

Pi : RF power at the input of the antenna of the transmit station, that gets radiated, considered in the non geostationary-satellite system (dBW) in the reference bandwidth

i : off-axis angle between the boresight of the transmit station considered in the non geostationary-satellite system and the direction of the GSO receive station

Gt(i)  : transmit antenna gain (as a ratio) of the station considered in the non geostationary-satellite system in the direction of the GSO receive station

di : distance (m) between the transmit station considered in the non geostationary-satellite system and the GSO receive station

i : off-axis angle between the boresight of the antenna of the GSO receive station and the direction of the ith transmit station considered in the non geostationary-satellite system

Gr(i)  : receive antenna gain (as a ratio) of the GSO receive station in the direction of the ith transmit station considered in the non-geostationary-satellite system

Gr,max : maximum gain (as a ratio) of the antenna of the GSO receive station.
ANNEX 2

epfdup and epfdis limits for certain FSS allocations

The epfdup produced at any point in the GSO by emissions from all the earth stations in a non-geostationary-satellite system in the FSS in the frequency bands listed in Table 1, for all conditions and for all methods of modulation, should not exceed the limits given in Table 1 for the specified percentages of time. These limits relate to the epfd which would be obtained under free-space propagation conditions, into a reference antenna and in the reference bandwidth specified in RR Table S22-1, for all pointing directions towards the Earth's surface visible from the GSO.

TABLE 1

Limits to the epfdup radiated by non-GSO FSS systems
in certain frequency bands


Frequency band
(GHz)

epfdup
(dB(W/m2))

Percentage of time during which epfd level may not be exceeded

Reference bandwidth
(kHz)

Reference GSO space station antenna beamwidth and reference radiation pattern

12,5-12,75
12,75-13,25
13,75-14,5

–160

100

40


Rec. ITU-R S.672, Ls  –20(1)

27.5-28.6
29.5-30.0

–162

100

40

1.55°
Rec. ITU-R S.672, Ls  –10(1)

(1) For the case of Ls  –10, the values a  1.83 and b  6.32 should be used in the equations in Annex 1 of Recommen­dation ITU R S.672 for single-feed circulars beams. In all cases of Ls, the parabolic main beam equation should start at zero.

The epfdis, produced at any point in the GSO orbit by emissions from all the space stations in a non-geostationary-satellite system in the FSS in the frequency bands listed in Table 2, including emissions from a reflecting satellite, for all conditions and for all methods of modulation, should not exceed the limits given in RR Table S22-2 for the specified percentages of time. These limits relate to the epfd which would be obtained under free-space propagation conditions into a reference antenna and in the reference bandwidth specified in Table 2, for all pointing directions towards the Earth's surface visible from the GSO.



TABLE 2

Limits to the epfdis radiated by non-GSO FSS systems
in certain frequency bands


Frequency band
(GHz)

epfdis
(dB(W/m2))

Percentage of time during which epfd level may not be exceeded

Reference bandwidth
(kHz)

Reference GSO space station antenna beamwidth and reference radiation pattern

10.7-11.7 in Region 1
12.5-12.75 in Region 1
12.7-12.75 in Region 2
17.8-18.4

–160

100

40


Rec. ITU-R S.672, Ls  –20




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