CEPT
ECC
SE19(14)04
Electronic Communications Committee
Project Team SE19
Web-Meeting, 28th November 2013
Source: Orange
Subject: SE19 WI28: Coexistence study between FS and FSS.
Group membership required to read? (Y/N): N
Summary: This document presents a correction to the study assessing compatibility
between fixed service with narrow channels in the L6 band and FSS in the band 5925 MHz –
6425 MHz.
Proposal: SE19 is invited to consider this contribution for potential inclusion in ECC draft
report (to complete or replace the previous study on this matter).
Background: at last SE19 meeting, it was noticed that some calculations provided by Orange
on interferences from FS to FSS had to be corrected.
Methodology
The “ΔT/T” approach derived from ECC Report 68
The study adopted the ΔT/T approach described in Appendix 8 of the ITU Radio Regulations in
order to assess the impact of interference from a large number of FS devices in the field-of-view
of a satellite antenna beam. Although not directly suitable for use in the case of inter-service
sharing, it does provide a very simple method of analysing the impact without much knowledge
of the characteristics of the carriers used on the satellite network requiring protection. In this
technique, the interference from the FS into the satellite receivers is treated as an increase in
thermal noise in the wanted FSS network and hence is converted to a noise temperature (by
considering the interference power per Hz) and compared with tolerable percentage increases
in noise temperature. This approach has the advantage that very few satellite parameters are
required to be known and a detailed link budget for every type of carrier (especially those most
sensitive to interference) is not required for the satellite network requiring protection
Recommendation ITU-R S.1432 deals with the allowable error performance degradations to the
FSS below 30 GHz. For sharing studies with systems having co-primary status, a 6% of the
aggregate interference budget is recommended.
The study takes only into account the uplink case.
The limitation of increase of equivalent noise temperature is expressed by the following
relationship:
(∆Tsat)/Tsat < Y (%)
where,
ΔTsat :
apparent increase in the receiving system noise temperature at the satellite, due to
an interfering emission (K);
Tsat: the receiving system noise temperature at the satellite referred to the output of the
receiving antenna of the satellite (K)
Y : noise increase allowed (6% in case of FS).
In the case under consideration here, ΔTsat is the contribution of aggregate emissions from FS
P-P devices at the input of satellite receiver.
Assuming that FS P-P interference can be treated similarly to thermal noise, the following
relationship can be assumed (linear scale, not dB):
∆Tsat=(EIRP_FS∙Gsat)/(k∙l)
K
where
E.I.R.P_FS : the aggregate E.I.R.P spectral density of the FS P-P transmitters in the satellite
beam and in the direction of the satellite (W*Hz-1);
Gsat: the gain of receiving antenna of the satellite in the direction of FS interferer (linear ratio,
relative to isotropic);
k : Boltzmann’s constant (1.38x10-23 J.K-1);
l : uplink Free Space path loss (linear power ratio). Note that this could also include gaseous
attenuation due to absorption by water vapour and oxygen molecules;
Combining above equations:
EIRP_FS ≤ X∙(Gsat/Tsat)-1∙k∙l
W.Hz-1
where,
X: noise increase allowed (expressed as a fraction of 1, e.g. 0.06 for 6%).
Consideration on the contributions of the different European countries to interferences to
satellites
Just as in the ECC report 68, we have considered the different European countries with their
population. The relative population compared to the total population gives the percentage of
interferences coming from this country (if we consider that the FS number is proportional to the
population). We consider that all the FS are located in one location of the country (actually the
capital of the country). From this location, we derive the elevation between the FS and the
satellite and from this elevation we deduce the antenna gain according to ITU-R F.1245-2.
Horizontal discrimination :
We have no knowledge concerning horizontal orientation of the FS’s antennas in relation to the
direction of the victim satellite.
2
We can assume that all directions of FS are equally probable. We should consider only FS
which give substantial contribution to the aggregated level of interferences to the victim satellite.
Indeed the FS antennas have very sharpened antenna patterns. So we take into account only
FS’s antennas that are pointed in the direction to the victim satellite (it means in an interval of
angles where we consider that the transmitted power may interfere the satellite receiver). We
consider that relative attenuation of the FS antenna radiation pattern at the border of this
interval should be -10 dB. Based on the antenna radiation pattern present in ITU-R F.1245-2 we
found that this -10 dB level is achieved for the angle of 2,65°.
Based on these assumptions the number of FS’s that are really interfering satellites may be
approximated by the ratio of 2*2,65°=5,3° to 360°. This ratio is equal to 0,0147 (which gives 18,3 dB in logarithm scale).
The figure below gives the antenna pattern from ITU-R F.1245-2 on which is based the
horizontal discrimination assumption :
ATPC (Automatic Transmitted Power Control)
In our calculations, we consider the Automatic Transmitted Power Control. The reduction of
power taken into account for this ATPC is here of 9 dB.
The ATPC is for example recommended for fixed services in Recommendation ITU-R F.1247-1
:
“Technical and operational characteristics of systems in the fixed service to facilitate sharing
with the space research, space operation and Earth exploration-satellite services operating in
the bands 2 025-2 110 MHz and 2 200-2 290 MHz”
Here is an excerpt of this recommendation :
3
“[…]
recommends
1
that FS stations in the bands 2 025-2 110 MHz and 2 200-2 290 MHz, where practicable,
use:
1.1 automatic transmit-power control (ATPC) such that the mean power is a minimum 10 dB
below the maximum transmitter power;
[…]
”
Of course, this recommendation is for another frequency band than the 6 GHz band but anyway
it shows that ATPC can be used for this kind of sharing between FS and satellite receivers.
Input parameters used in calculations
Input parameters
values
f [GHz]
d [km]
Y=ΔT/T [%]
B [MHz]
Tx power [dBW]
ATPC [dB]
Feeder loss [dB]
Tx antenna gain [dBi]
FS antenna Horizontal discrimination [dB]
5925
38000
6
0,5
-3
9
2
36
-18,3
Satellite Satellite
Satellite
orbital Maximum
Receiving
position Receive
System
Gain,
Noise
Gsat (dBi) Temperature
Tsat (K)
359o
East
32.8
700
66o East
34.7
700
53o East
26.5
1200
3o East
34
773
Results
In the next table, we give the number of active devices transmitting simultaneously based on the
methodology described above. For each satellite, we can see the number of allowed active FS
P-P ranges from about 15000 to 347000. These figures are very high compared to the order of
magnitude for these FS figures which are about 3000 all over Europe. Therefore it seems that
there wouldn’t be harmful interferences from FS to satellite receivers according to these
calculations especially if these FS would use the ATPC. Note that a ATPC of 9 dB may be a too
high value especially if we consider a lower output transmit power for the FS (e.g. -7 dBW).
4
Satellite
position
orbital Satellite
Receiving
System Figure of
Merit Gsat/Tsat
Max allowable aggregate
EIRP
spectral density
and EIRP
from all FS P-P devices
in one
channel
for
ΔTsat/Tsat=6%
Number N of
active FS P-P
devices
(transmitting
simultaneously
in one channel)
dB/K
dBW/Hz
dBW
E
4,35
-45,7
11,32
94 041
E
6,25
-47,6
9,42
15 026
E
-4,29
-37,0
19,96
347 024
E
5,12
-46,4
10,55
83 317
359o
66o
53o
3o
The next figure gives the number of FS devices versus the Tx output power. For a 2 dBW
power, the minimum number of FS would be 4752. This number is higher than the number of FS
used currently used over Europe in the L band (about 3000). This means that if we set a -7 dBW
output power, the ATPC would even not be necessary to be used (because for 2 dBW, the
equivalent power is 2-9=-7 dBW, where 9 is ATPC). Therefore, according to this figure, if we
consider a -3 dBW output power, the ATPC could be 4 dB.
The next figure gives the number of FS devices versus FS antenna horizontal discrimination. It
shows that at least for -12 dB antenna discrimination, the number of FS devices is still very high
(at least higher than 3000 in the worst case). It would mean that for an angle aperture of 11.3
degrees could be used in the calculations instead of 2.25 degrees. In this case, we would have
360/22.6=15.9 which converted in dB would give 12 dB (to be compared to 18.3 dB).
5
Annex : detail of the calculations
In the table below, we give the location of the capital of each European country. Then we give
the contribution of each country to ∆T/T proportionally to the population of each country.
Latitude Longitude
(⁰)
(⁰)
Austria
(Vienna)
Belgium
(Brussels)
Bulgaria
(Sofia)
Czech
Republic
(Prague)
Denmark
(Copenhagen)
Estonia
(Tallin)
Finland
(Helsinki)
France (Paris)
Germany
(Frankfurt)
Greece
(Athens)
Population
Contribution
to 6%
48,2
16,4
millions
8,2
50,8
4,4
10,3
1,65
0,099
42,7
23,3
7,7
1,23
0,074
50,1
14,4
10,3
1,65
0,099
55,7
12,6
5,4
0,86
0,052
59,5
24,8
1,4
0,22
0,013
60,0
25,0
5,2
0,83
0,050
48,5
50,1
2,4
8,7
59,8
83,0
9,55
13,26
0,573
0,796
38,0
23,7
10,6
1,69
0,102
6
%
1,31
0,079
Hungary
(Budapest)
Ireland
(Dublin)
Israel ( )
Italy (Rome)
Latvia (Riga)
Lithuana
(Vilnius)
Luxmebourg
Netherlands
(Amsterdam)
Norway
(Oslo)
Poland
(Warsaw)
Portugal
(Lisbon)
Romania
(Bucharest)
Slovakia
(Bratislava)
Spain
(Madrid)
Sweden
(Stockholm)
Switzerland
(Zurich)
Turkey
(Ankara)
UK (London)
Ukraine
(Kijev)
Others
47,5
19,1
10,1
1,61
0,097
53,0
-6,3
3,9
0,62
0,037
32,1
41,9
56,9
54,7
34,8
12,1
24,1
25,3
6,0
58,0
2,4
3,6
0,96
9,27
0,38
0,58
0,058
0,556
0,023
0,035
49,6
52,4
6,1
4,9
0,4
16,0
0,06
2,56
0,004
0,153
59,9
10,8
4,5
0,72
0,043
52,3
21,0
39,0
6,23
0,374
38,7
-9,1
10,1
1,61
0,097
44,4
26,1
22,3
3,56
0,214
48,2
17,1
5,4
0,86
0,052
40,3
-3,4
40,0
6,39
0,383
59,3
18,1
8,9
1,42
0,085
47,4
8,5
7,3
1,17
0,070
39,8
31,9
67,3
10,75
0,645
51,5
50,4
0,0
30,6
59,8
48,0
9,55
7,67
0,573
0,460
11,0
1,76
0,105
625,9
100,0
6,0
TOTAL
ΔT/T
Based on the calculation method described above, we can find the number N of acceptable
fixed devices for each of the 4 considered satellites in the 4 different tables below. At first, we
derive the number of acceptable number of FS per country and at the end we add the
contributions of each country in order to find the total number of acceptable FS over the whole
Europe.
Calculation example :
We first calculate the EIRP density allowed at satellite receiver :
EIRP density=( ΔT/T)*k*L*(Gsat/Tsat)-1
EIRP density=10*Log(ΔT/T)+10*Log(k)+10*Log(L)-Gsat(dBi)+10*Log(Tsat)
EIRP
density
(dBW/Hz)=10*Log(0.079/100)+10*Log(1.38.1023)+32.45+20*Log(38000)+20*Log(5925)-34+10*Log(773)
7
0,079 is the contribution to 6 % from Austria (see table above)
Then we calculate the transmitted power of the FS to the satellite receiver
EIRP_channel=Tx power-ATPC+FS antenna gain-feeder losses
EIRP_channel (dBW)=-3-9-6.1-2=-20.1 dBW
then we deduce the number of allowed FS (N_linear) by dividing the EIRP density allowed at
satellite receiver by the power density of a FS (B being the bandwidth of this FS) :
N_linear=[EIRP density/(EIRP_channel/B)]*Horizontal_antenna discrimination
«Horizontal_antenna discrimination» being in linear : 360/5.3=68
We multiply the calculated number by Horizontal_antenna discrimination=360/5.3 to take into
account the fact that only a fraction of the total number of FS will indeed interfere the satellite
receiver due the horizontal discrimination of FS antennas.
Finally we do this calculation for each country and at the end we add the numbers of FS for
each country and we have the total number of allowed FS. We do the same kind of calculation
for each satellite.
Satellite
D
3E
EIRP
density
El.
Angle
dBW/Hz
-65,3
-64,3
-65,5
-64,3
-67,1
-72,9
-67,2
-56,6
-55,2
-64,2
-64,4
-68,5
-66,6
-56,8
-70,6
-68,8
-78,4
-62,4
-67,9
-58,5
-64,4
-60,9
-67,1
[°]
33,2
31,8
36,6
31,6
25,9
20,0
19,4
34,3
32,3
40,9
33,2
28,8
39,4
40,7
22,6
24,5
33,1
30,1
21,7
27,9
43,4
33,9
33,0
FS
Antenna
Gain
dBi
-6,1
-5,6
-7,2
-5,6
-3,4
-0,6
-0,3
-6,5
-5,8
-8,4
-6,1
-4,6
-8,0
-8,3
-1,9
-2,8
-6,1
-5,0
-1,5
-4,2
-9,0
-6,3
-6,0
Eirp
channel
dBW
-20,1
-19,6
-21,2
-19,6
-17,4
-14,6
-14,3
-20,5
-19,8
-22,4
-20,1
-18,6
-22,0
-22,3
-15,9
-16,8
-20,1
-19,0
-15,5
-18,2
-23,0
-20,3
-20,0
N
1029,9
1161,5
1234,0
1143,3
364,6
49,5
170,5
8148,1
9732,0
2242,5
1268,5
343,3
1156,1
12120,8
115,2
211,5
49,9
1572,7
195,2
3171,0
2478,4
2950,7
668,0
8
-58,4
-64,9
-65,8
-56,1
-56,6
-57,6
-64,0
-46,44
Satellite
F
53E
EIRP
density
dBW/Hz
-55,9
-54,9
-56,1
-54,9
-57,7
-63,5
-57,8
-47,2
-45,8
-54,7
-55,0
-59,1
-57,2
-47,4
-61,2
-59,4
-69,0
-53,0
-58,5
-49,1
-55,0
-51,5
-57,7
-49,0
-55,5
-56,4
-46,7
-47,2
-48,2
-54,6
-37,03
43,0
21,4
35,3
35,2
31,0
26,6
31,4
-8,9
-1,3
-6,8
-6,7
-5,4
-3,7
-5,2
-22,9
-15,3
-20,8
-20,7
-19,4
-17,7
-19,2
9590,7
372,9
1068,8
9783,4
6327,4
3463,9
1133,3
83 317
El.
Angle
[°]
24,4
16,3
32,4
22,1
17,1
18,4
17,9
16,5
19,1
36,5
26,3
9,3
47,8
26,4
20,4
22,8
18,0
15,7
13,3
23,3
12,9
32,2
24,8
16,7
16,4
20,8
39,0
13,6
28,4
22,4
FS
Antenna
Gain
dBi
-2,8
1,6
-5,8
-1,7
1,1
0,3
0,6
1,5
-0,1
-7,1
-3,6
7,7
-10,1
-3,6
-0,8
-2,0
0,5
2,0
3,8
-2,3
4,2
-5,8
-2,9
1,4
1,6
-1,0
-7,9
3,6
-4,4
-1,1
EIRP
channel
dBW
-16,8
-12,4
-19,8
-15,7
-12,9
-13,7
-13,4
-12,5
-14,1
-21,1
-17,6
-6,3
-24,1
-17,6
-14,8
-16,0
-13,5
-12,0
-10,2
-16,3
-9,8
-19,8
-16,9
-12,6
-12,4
-15,0
-21,9
-10,4
-18,4
-15,1
N
4163,0
1907,3
7942,8
4082,6
1127,2
351,0
1216,9
11416,5
22844,5
14728,5
6184,9
177,6
16362,2
35855,7
778,8
1542,6
94,9
2697,7
501,1
17643,1
1042,1
22649,8
2855,2
7869,9
1673,5
2486,6
110356,3
7041,6
35617,0
3812,9
347 024
9
Satellite
H
66E
EIRP
density
dBW/Hz
-66,4
-65,4
-66,7
-65,4
-68,2
-74,1
-68,4
-57,8
-56,3
-65,3
-65,5
-69,6
-67,8
-57,9
-71,7
-70,0
-79,5
-63,5
-69,0
-59,6
-65,5
-62,1
-68,2
-59,5
-66,0
-66,9
-57,3
-57,8
-58,7
-65,1
-47,57
Satellite
I
359E
EIRP
density
El.
Angle
[°]
17,3
8,9
24,8
15,1
11,1
14,0
13,7
8,5
11,8
28,0
19,3
1,9
39,8
17,7
15,6
17,7
10,4
8,6
8,0
17,4
2,9
25,4
17,7
7,0
11,5
12,9
32,1
6,0
23,3
15,5
FS
Antenna
Gain
dBi
1,0
8,2
-2,9
2,5
5,8
3,3
3,5
8,7
5,1
-4,3
-0,2
29,9
-8,1
0,7
2,1
0,7
6,5
8,6
9,3
0,9
20,4
-3,2
0,7
10,8
5,4
4,2
-5,7
12,5
-2,3
4,3
EIRP
channel
dBW
-13,0
-5,8
-16,9
-11,5
-8,2
-10,7
-10,5
-5,3
-8,9
-18,3
-14,2
15,9
-22,1
-13,3
-11,9
-13,3
-7,5
-5,4
-4,7
-13,1
6,4
-17,2
-13,3
-3,2
-8,6
-9,8
-19,7
-1,5
-16,3
-9,7
N
155,6
37,1
359,5
139,1
33,8
15,6
55,1
192,0
605,1
670,3
251,9
0,1
913,9
1165,2
35,2
72,3
2,1
52,9
12,4
750,7
2,2
1105,2
108,5
79,0
60,8
66,5
5988,5
80,4
1917,2
97,6
15 026
El.
Angle
FS
Antenna
Gain
EIRP
channel
N
10
dBW/Hz
-64,5
-63,5
-64,8
-63,5
-66,3
-72,2
-66,5
-55,9
-54,4
-63,4
-63,6
-67,7
-65,9
-56,0
-69,8
-68,1
-77,6
-61,6
-67,1
-57,7
-63,6
-60,2
-66,3
-57,6
-64,1
-65,0
-55,4
-55,9
-56,8
-63,2
-45,67
[°]
32,2
31,6
34,9
30,8
25,4
19,0
18,5
34,2
31,8
39,0
32,0
29,2
36,4
39,8
21,5
23,3
32,7
29,9
21,3
26,8
44,4
32,1
32,0
43,4
20,7
34,8
32,9
31,1
25,0
30,6
dBi
-5,8
-5,6
-6,6
-5,3
-3,2
0,0
0,2
-6,4
-5,6
-7,9
-5,7
-4,7
-7,1
-8,1
-1,4
-2,3
-5,9
-5,0
-1,3
-3,8
-9,3
-5,7
-5,7
-9,0
-1,0
-6,6
-6,0
-5,4
-3,0
-4,9
dBW
-19,8
-19,6
-20,6
-19,3
-17,2
-14,0
-13,8
-20,4
-19,6
-21,9
-19,7
-18,7
-21,1
-22,1
-15,4
-16,3
-19,9
-19,0
-15,3
-17,8
-23,3
-19,7
-19,7
-23,0
-15,0
-20,6
-20,0
-19,4
-17,0
-18,9
1138,9
1364,9
1308,0
1280,1
414,5
52,0
180,7
9656,1
11173,3
2376,9
1381,1
424,2
1132,2
13682,7
121,4
222,7
57,7
1846,4
222,4
3423,3
3132,0
3073,3
738,4
11717,1
409,6
1231,1
9863,8
7614,5
3541,0
1260,1
94 041
11