CEPT
ECC/CPG15
ECC
CPG PTB(2013)055
Electronic Communications Committee
3rd meeting CPG-15 PTB
Copenhagen, 21-23 August 2013
Date issued:
09 August 2013
Source:
Luxembourg
A.I. 1.6 – Compatibility studies related to the band 13.25-13.75 GHz
between EESS (active) / SRS and FSS (E-s)
N
Password protection required:
Subject:
Summary:
This study shows the results of compatibility studies from a new FSS (E-s) allocation in the band 13.25-13.75
GHz towards EESS (active) / SRS networks current and future.
Considering the deployment model developed by the WP4A to be used for statistical and dynamic simulations,
considering the adequate number of FSS stations deployed worldwide, the dynamic simulations presented in
this document depict situations where the EESS (active) protection criteria is never exceeded for all kinds of
sensors considered, with a positive margin ranging from 4.4 to 39 dB. This therefore confirms that FSS (Earthto-space) and EESS (active) seem to be compatible.
Considering the protection of the ACES system operating under the SRS allocation, under similar scenario, the
protection criterion defined in the liaison statement from 7B to 4A for the protection of the ACES system is
exceeded by only 0.5 dB considering the worst case situation (i.e. one transponders of 125 MHz). The level of
protection criteria of the ACES system (i.e. -125 dBW/125 MHz) is respected for 0.106% instead 0.1%.
Considering a practical situation (e.g. 4 transponders of 26 MHz in 125 MHz), this level of protection falls
down to -125.4 dBW/125 MHz which is 0.4 dB below the required criteria. This therefore confirms that FSS
(Earth-to-space) and SRS seem to be compatible.
Proposal:
In view of these study results, CPG PTB is invited to consider the band 13.25-13.75 GHz as a potential band for
FSS (Earth-to-space) allocations under WRC-15 Agenda item 1.6.
1
1. Introduction
At the last PT B meeting (March 2013), ESA made a contribution (i.e. doc. CPG PTB(2013)019 “Agenda item 1.6 –
Sharing studies with EESS (active) and SRS”) showing dynamic analyses with FSS (Earth-to-space) and all types of
active sensors used in the EESS (active). As highlighted in the minutes of the meeting (i.e. doc. CPG PTB(2013)042),
“some concerns were expressed regarding assumptions used for these sharing studies (e.g. VSAT deployment model,
limitation to only 1 type of FSS uplink antenna)”.
On this subject, WP4A May 2013 meeting developed a more detailed FSS deployment model to be used for statistical
and dynamic analyses. In complement to this model, a contribution to this meeting (i.e. doc. CPG PTB(2013)046)
provide a frequency reuse factor level based on the current fleet of a Luxembourgish operator.
This contribution reproduces the dynamic analyses with FSS (E-s) and all types of active sensors used in the EESS
(active) as performed by ESA at the last meeting using the up-to-date FSS deployment model.
2. FSS deployment model
Documents 4A/242 Annex 5 and CPG PTB(2013)046 give characteristics of FSS deployment model provided by two
satellite operators based on current deployment observed on their own Ku FSS fleet. Due to some missing information
on the model proposed by the FSS1 operator, only the deployment model proposed by the FFS2 operator was retained
to be taken into account in sharing and compatibility studies performed in this document. These parameters are
reproduced in Table 1 below.
Transmit earth station
diameter (DES)
TABLE 1
FSS2 deployment model
Average
Percentage of
bandwidth
total
(MHz)
bandwidth
Average power
density
(dBW/Hz)
DES <= 75 cm
2.2
0.3%
–55.0
75 cm < DES <= 1.2 m
0.6
9.4%
–53.8
1.2 m < DES <= 1.8 m
0.5
3.4%
–56.1
1.8 m < DES <= 2.4 m
4.5
35.2%
–56.8
2.4 m < DES <= 4.5 m
26.2
8.7%
–54.8
4.5 m < DES <= 9 m
23.9
26.3%
–59.9
DES > 9 m
9.4
16.7%
–67.6
2
3. EESS(active) and SRS characteristics
These characteristics are exactly the same as used in the doc. CPG PTB(2013)019 and they are summarized in
Table 2 for 3 different types of sensors and ACES system located on the International Space Station (ISS).
TABLE 2
Characteristics of current flying spaceborne active sensors in the 13.25-13.75 GHz band
Parameters
Active sensor type and mission
Altimeter
JASON-1/2/3
SENTINEL-3
Scatterometer
QuickSCAT Seawinds
Precipitation radar
TRMM/
Orbit altitude, km
1 336 (JASON)
815 (SENTINEL-3)
803
350
Orbit inclination, deg
66 (JASON)
98 (SENTINEL-3)
98.2
35
Antenna type
1.2 m diameter parabolic
dish
1 m diameter parabolic
dish
Planar array
Antenna polarization
Linear
Horizontal (inner),
Vertical (outer)
Horizontal
Antenna peak gain, dBi
43.9
41.0
47.7
Antenna elevation
beamwidth, deg
1.28
1.6 (inner),
1.4 (outer)
0.71
Antenna azimuth
beamwidth, deg
1.28
1.8 (inner),
1.7 (outer)
0.71
Antenna beam look
angle, deg
0
40 (inner),
46 (outer)
–17 to +17
Antenna scan range, deg
0
0 to 360
–17 to +17 (cross track)
Antenna scan period, sec
0
3.33 (18 rpm)
0.7
Antenna pointing
Fixed at nadir
Circular scanning in
azimuth
Scanning across nadir
track
Centre RF frequency,
GHz
13.575 GHz and 13.285
GHz (JASON)
13.575 GHz (SENTINEL3)
13.402
13.597-13.796 GHz
13.603-13.802 GHz
Receiver bandwidth,
MHz
320 to 350
0.40
1
Protection criterion
–142 dBW/MHz
–195 dBW/Hz or
–135 dBW/MHz
–150 dBW/600 kHz
(for I/N of –10 dB) or
– 147.8 dBW/MHz
Comments
Nadir looking
Rotating dish antenna
with two spot beams
sweeping a circular
pattern. QuickSCAT has
4 look angles and the
resolution in conical
scan mode is 50 km.
Two channel frequency
agility; cross track
antenna scanning
The percentage of time associated with the protection criterion is 1% for the altimeter and scatterometer (systematic
interference), and 0.2% for the precipitation radar, according to recommendation ITU-R RS.1166.
3
TABLE 3
Characteristics of SRS in the band 13.4-1.75 GHz
Parameter
Value
Orbit altitude, km
356
Orbit inclination, deg
51.64
Frequency band
13.4-13.75 GHz
Center frequency
13.475 GHz
Occupied bandwidth
125 MHz
E/S emission power
3 dBW
Maximum E/S power spectral density
-79.5 dBW/Hz
E/S Feeder loss
1.5 dB
Maximum E/S antenna gain
32 dBi
Spacecraft receiver noise temperature
730 K
Spacecraft antenna gain
+6.5 dBic max. to >-0.2dBic for ±70°
Polarization
LHCP
Protection Criteria
Recommendations ITU-R SA.609 and ITU-R SA.1743
Recommendation ITU-R SA.609 recommends a protection level of -177 dBW/kHz to be exceeded less than
0.1% of the time. This is based on an I/N of -6 dB. Keeping this I/N ratio and considering a band of 125 MHz
with a noise temperature of 730 K and no apportionment would lead to a protection level of -125 dBW in 125
MHz.
4. Simulations for altimeters SENTINEL-3 and JASON
According to the deployment model used and a frequency reuse factor of 1.2, 10,090 FSS Earth stations have
been deployed worldwide in a frequency band of 250 MHz (see Figure 1). Each FSS Earth station is pointing to
one GSO satellite chosen randomly between a total of 120 GSO satellites, one each 3 degrees, provided that a
minimum elevation angle of 10° is respected. The Table 4 is an embedded excel file which contains all formula.
FIGURE 1
Location of the 10,090 FSS Earth stations
4
TABLE 4
FSS antenna characteristics used in simulations for altimeters (Worst case)
FSS2 Data
Nyquist
Average Power
Occupied Bandwidth allocated
Antenna Diameter
% of total
Average Tx
Number of
bandwidth
Density
bandwidth
to each type of
type
(m)
Bandwidth
Power (dBW)
antenna
(MHz)
(dBW/Hz)
(MHz)
antenna (MHz)
Type 1
0.6
2.2
0.3%
-55
8.4
2.64
108
41
Type 2
1
0.6
9.4%
-53.8
4.0
0.72
3384
4,700
Type 3
1.5
0.5
3.4%
-56.1
0.9
0.6
1224
2,040
Type 4
2.1
4.5
35.2%
-56.8
9.7
5.4
12672
2,347
Type 5
3.5
26.2
8.7%
-54.8
19.4
31.44
3132
100
Type 6
7
23.9
26.3%
-59.9
13.9
28.68
9468
330
Type 7
10
9.4
16.7%
-67.6
2.1
11.28
6012
533
Total
10,090
The SENTINEL-3 and JASON orbits are simulated during 27 days with a time step of 1 minute.
The antenna patterns used for JASON and SENTINEL-3 are the same as used in the documents CPG
PTB(2013)019 and 4A/168.
As shown in figure 2, the 10,090 FSS Earth stations create an interference level of -133.5 dBW for 1% of the
time in SENTINEL-3 SRAL receiver and -134.4 dBW for 1% of the time in JASON SRAL receiver, therefore
below the protection criterion of -117 dBW/320 MHz by more than 17 dB.
FIGURE 2
Cdf of interference received on SENTINEL-3 & JASON (Worst case)
For these simulations, an FSS transponder with a bandwidth of 250 MHz is assumed (worst case situation). In
practice, based on the type of service offer, this 250 MHz could be split in 8 transponders of 26 MHz or 6
transponders of 36 MHz or 4 transponders of 54 MHz or 3 transponders of 72 MHz or a mixt. Therefore, due to
the required guard band between transponders, in any case the occupied bandwidth will be equal to 250 MHz but
around 210/220 MHz. Therefore, if we consider 8 transponders of 26 MHz, the occupied bandwidth will be
equal to 208 MHz and the maximum number of FSS Earth station which could be deployed worldwide will be
equal to only 8,395, which represent a reduction of around 23% of the total number of Earth station considered
in these simulations.
5
5. Simulations for the scatterometer QuickSCAT
As the protection criteria and wanted carrier are in a bandwidth of 1 MHz, we considered that one Earth station
has a bandwidth of at least 1 MHz. Therefore, as we considered 120 GSO satellites, one each 3 degrees, with a
frequency reuse factor of 1.2, 144 (120 x 1.2) FSS Earth stations (number of GSO satellite x frequency reuse
factor) have been deployed worldwide in a frequency band of 1 MHz (see Figure 3). Each FSS Earth station is
pointing to one GSO satellite chosen randomly between a total of 120 GSO satellites, one each 3 degrees,
provided that a minimum elevation angle of 10° is respected. The same repartition of Antennas deployed in 250
MHz observed in Table 4 is used to assess the number of each type of antenna in 1 MHz. The Table 5 is an
embedded excel file which contains all formula.
FIGURE 3
Location of the 144 FSS Earth stations
TABLE 5
FSS antenna characteristics used in simulations for scatterometer
SES Data
Nyquist
Average Power
Number of
Antenna Diameter
% of total
Average Tx
bandwidth
Density
antenna in
type
(m)
Bandwidth
Power (dBW)
(MHz)
(dBW/Hz)
250 MHz
Type 1
Type 2
Type 3
Type 4
Type 5
Type 6
Type 7
0.6
1
1.5
2.1
3.5
7
10
2.2
0.6
0.5
4.5
26.2
23.9
9.4
0.3%
9.4%
3.4%
35.2%
8.7%
26.3%
16.7%
-55
-53.8
-56.1
-56.8
-54.8
-59.9
-67.6
8.4
4.0
0.9
9.7
19.4
13.9
2.1
Total
41
4,700
2,040
2,347
100
330
533
10,090
Number of antenna
in 1 MHz
Exact
0.58
67.07
29.11
33.49
1.42
4.71
7.61
Arrondi
1
67
29
33
2
5
7
144
The QuickSCAT orbits are simulated during 4 days with a time step of 3.33 second.
The antenna patterns used for QuickSCAT are the same as used in the documents CPG PTB(2013)019.
As shown in figure 4, the 144 FSS Earth stations create an interference level of -163 dBW for 1% of the time in
QuickSCAT receiver, therefore below the protection criterion of -135 dBW/1 MHz by more than 28 dB.
6
FIGURE 4
Cdf of interference received on QuickSCAT generated by all antennas as defined in Table 5
As the number of Earth stations considered in these simulations is relatively low (only 144 compared to the 10,090
in 250 MHz), the statistical antenna type repartition as defined in Table 5 may not be observed in practice. Therefore
similar simulations are performed considering that only 1 type of antenna is used for each of the 144 FSS Earth
stations.
As shown in figure 5 and Table 6, even if only 1 type of antenna is considered, the 144 FSS Earth stations create an
interference level that is below the protection criterion of -135 dBW/1 MHz by between 26 dB up and 39 dB.
FIGURE 5
Cdf of interference received on QuickSCAT generated by each type of antenna
7
TABLE 6
Results of the simulation for each type of antenna
Antenna interference level in dBW
Type
for 1% of the time
Type 1
-161.2
Type 2
-162.1
Type 3
-165.2
Type 4
-163.4
Type 5
-160.9
Type 6
-166.5
Type 7
-173.7
6. Simulations for the precipitation radar
As the frequency bandwidth used to perform the interference evaluation is equal to 1 MHz as used for the
scatterometer, the same FSS antenna characteristics (see Table 5 and Figure 3) are used in these simulations.
Therefore, 144 FSS Earth stations have been deployed worldwide in a frequency band of 1 MHz. Each FSS
Earth station is pointing to one GSO satellite chosen randomly between a total of 120 GSO satellites, one each 3
degrees, provided that a minimum elevation angle of 10° is respected.
The TRMM orbits are simulated during 4 days with a time step of 1 second.
The antenna patterns used for TRMM are the same as used in the documents CPG PTB(2013)019 (i.e. ITU-R
Rec. S. 672-3 with Ln=-30 dB)
As shown in figure 6, the 144 FSS Earth stations create an interference level of -154.3 dBW for 0.2% of the time
in TRMM receiver, therefore below the protection criterion of -147.8 dBW/1 MHz by more than 5 dB.
FIGURE 6
Cdf of interference received on TRMM generated by all antennas as defined in Table 5
As the number of Earth stations considered in these simulations is relatively low (only 144 compared to the 10,090
in 250 MHz), the statistical antenna type repartition as defined in Table 5 may not be observed in practice. Therefore
similar simulations are performed considering only 1 type of antenna for each of the 144 FSS Earth stations.
8
As shown in figure 7 and Table 7, even if only 1 type of antenna is considered, the 144 FSS Earth stations create an
interference level that is below the protection criterion of -147.8 dBW/1 MHz by between 4.4 dB and 17.4 dB.
FIGURE 7
Cdf of interference received on TRMM generated by each type of antenna
TABLE 7
Results of the simulation for each type of antenna
Antenna interference level in dBW
Type
for 0.2% of the time
Type 1
-152.4
Type 2
-153.5
Type 3
-156.6
Type 4
-154.7
Type 5
-152.2
Type 6
-157.8
Type 7
-165.2
9
7. ESA system ACES
According to the deployment model used and a frequency reuse factor of 1.2, 5,045 FSS Earth stations have been
deployed worldwide in a frequency band of 125 MHz (see Figure 8). Each FSS Earth station is pointing to one
GSO satellite chosen randomly between a total of 120 GSO satellites, one each 3 degrees, provided that a
minimum elevation angle of 10° is respected. The Table 8 is an embedded excel file which contains all formula.
FIGURE 8
Location of the 5,045 FSS Earth stations
TABLE 8
FSS antenna characteristics used in simulations for ESA system ACES (Worst case)
SES Data
Nyquist
Average Power
Occupied Bandwidth allocated
Antenna Diameter
% of total
Average Tx
Number of
bandwidth
Density
bandwidth
to each type of
Type
(m)
Bandwidth
Power (dBW)
antenna
(MHz)
(dBW/Hz)
(MHz)
antenna (MHz)
Type 1
0.6
2.2
0.3%
-55
8.4
2.64
54
20
Type 2
1
0.6
9.4%
-53.8
4.0
0.72
1692
2350
Type 3
1.5
0.5
3.4%
-56.1
0.9
0.6
612
1020
Type 4
2.1
4.5
35.2%
-56.8
9.7
5.4
6336
1173
Type 5
3.5
26.2
8.7%
-54.8
19.4
31.44
1566
50
Type 6
7
23.9
26.3%
-59.9
13.9
28.68
4734
165
Type 7
10
9.4
16.7%
-67.6
2.1
11.28
3006
266
Total
5045
The ESA system ACES orbits are simulated during 17 days with a time step of 1 minute.
The antenna patterns used for the ESA system ACES is the same as used in the documents CPG PTB(2013)019
and 4A/168 in Figure 18.
As shown in figure 9, the 5,045 FSS Earth stations create an interference level of -124.5 dBW for 0.1% of the
time in ACES receiver, therefore exceeding the protection criterion of -125 dBW/125 MHz by only 0.5 dB.
The level of protection criteria of the ACES system (i.e. -125 dBW/125 MHz) is respected for 0.106% instead
0.1%.
10
FIGURE 9
Cdf of interference received on ESA system ACES (Worst case)
For these simulations, an FSS transponder with a bandwidth of 125 MHz is assumed (worst case situation). In
practice, based on the type of service offered, these 125 MHz could be split in 4 transponders of 26 MHz or 3
transponders of 36 MHz or 2 transponders of 54 MHz or a mix. Therefore, due to the required guard band
between transponders, in any case the occupied bandwidth will be lower than 125 MHz, around 100/110 MHz.
Therefore, if we consider 4 transponders of 26 MHz, the occupied bandwidth will be equal to 104 MHz and the
maximum number of FSS Earth station which could be deployed worldwide will be equal to only 4,198, which
represent a reduction of around 17% of the total number of Earth station considered in these simulations.
In order to perform a simulation, 4,198 FSS Earth stations have been deployed worldwide in a frequency band of
125 MHz (see Figure 10). Each FSS Earth station is pointing to one GSO satellite chosen randomly between a
total of 120 GSO satellites, one each 3 degrees, provided that a minimum elevation angle of 10° is respected.
The Table 9 is an embedded excel file which contains all formula.
FIGURE 10
Location of the 4,198 FSS Earth stations
11
TABLE 9
FSS antenna characteristics used in simulations for ESA system ACES (Tpxs 26 MHz)
SES Data
Nyquist
Average Power
Occupied Bandwidth allocated
Antenna Diameter
% of total
Average Tx
Number of
bandwidth
Density
bandwidth
to each type of
Type
(m)
Bandwidth
Power (dBW)
antenna
(MHz)
(dBW/Hz)
(MHz)
antenna (MHz)
Type 1
0.6
2.2
0.3%
-55
8.4
2.64
44.928
17
Type 2
1
0.6
9.4%
-53.8
4.0
0.72
1407.744
1955
Type 3
1.5
0.5
3.4%
-56.1
0.9
0.6
509.184
849
Type 4
2.1
4.5
35.2%
-56.8
9.7
5.4
5271.552
976
Type 5
3.5
26.2
8.7%
-54.8
19.4
31.44
1302.912
41
Type 6
7
23.9
26.3%
-59.9
13.9
28.68
3938.688
137
Type 7
10
9.4
16.7%
-67.6
2.1
11.28
2500.992
222
Total
4198
As shown in figure 11, the 4,198 FSS Earth stations create an interference level of -125.4 dBW for 0.1% of the
time in ACES receiver, therefore below the protection criterion of -125 dBW/125 MHz by 0.4 dB.
FIGURE 11
Cdf of interference received on ESA system ACES (Txps 26 MHz)
12
8. Conclusion
Considering the deployment model developed by the WP4A to be used for statistical and dynamic simulations,
considering the adequate number of FSS stations deployed worldwide, the dynamic simulations presented in this
document depict situations where the EESS (active) protection criteria is never exceeded for all kinds of sensors
considered, with a positive margin ranging from 4.4 to 39 dB. This therefore confirms that FSS (Earth-to-space)
and EESS (active) seem to be compatible.
Considering the protection of the ACES system operating under the SRS allocation, under similar scenario, the
protection criterion defined in the liaison statement from 7B to 4A for the protection of the ACES system is
exceeded by only 0.5 dB considering the worst case situation (i.e. one transponders of 125 MHz). The level of
protection criteria of the ACES system (i.e. -125 dBW/125 MHz) is respected for 0.106% instead 0.1%.
Considering a practical situation (e.g. 4 transponders of 26 MHz in 125 MHz), this level of protection falls down
to -125.4 dBW/125 MHz which is 0.4 dB below the required criteria.
It is therefore proposed that the band 13.25-13.75 GHz be considered as a potential band for FSS (Earth-tospace) allocations under WRC-15 Agenda item 1.6.
13