CEPT
ECC PT1(17)094
ECC
Electronic Communications Committee
ECC PT1 # 55
Berlin, Germany, 24-28 April 2017
Date issued:
19th April 2017
Source:
ESA / EUMETSAT / DLR
Examples of exclusion zones that would be required around EESS and
SRS earth stations vs one single 5G base station
Subject:
Group membership required to read? (Y/N)
N
Summary:
This paper provides an update of the preliminary calculation of exclusion zones around EESS and
SRS earth stations in the band 25.5-27 GHz to protect them from harmful interference from one single
5G base station, following the finalization of 5G parameters by WP 5D.
Proposal:
To be considered when dealing with the protection of EESS and SRS. The terrain elevation around
the receiving EESS or SRS earth station is an important factor that will have to be accounted for
when determining the final exclusion zones.
Background:
See below.
1
Introduction
This paper aims at providing examples of calculation of exclusion zones around some existing or
planned EESS or SRS receiving earth stations operated by ESA, EUMETSAT and DLR. It should
be noted that those exclusion zones have been determined assuming a single 5G base station.
2
Single base station static analysis (Scenario 1a)
2.1
5G parameters assumed
Since the EESS and SRS earth stations are usually deployed in rural environment, a base station
in suburban open space hotspot was assumed, with an antenna height of 15 m and a tilt angle of
-15°. This would lead to the worst case separation distance since other types of base stations are
at a lower height.
The antenna panel is assumed to be pointing in the same azimuth as the victim earth station.
The base station input power is 10 dBm per element, or 28 dBm total, with an ohmic loss of 3 dB
and a maximum antenna gain of 23 dBi leading to a maximum EIRP of 48 dBm. The associated
bandwidth is 200 MHz.
Recommendation ITU-R M2101 developed by WP 5D provides an antenna pattern model for both
the BS and UE. The antenna pattern for a 8x8 elements 5G BS is provided below.
When assuming a -2.6° antenna pointing elevation for the BS (corresponding to an antenna height
of 15m, a UE height of 1.5m and a maximum distance of 300m for the BS), a BS antenna downtilt
of 15°, the maximum antenna gain at 0° elevation(horizon) is 22 dBi. The antenna discrimination
towards the horizon would therefore be 1 dB for these assumptions.
No additional cross polarization attenuation has been accounted for.
The overall maximum EIRP towards the horizon is therefore 28 dBm - 3 dB+ 22 dBi = 47 dBm in
200 MHz or 44 dBm/100 MHz, to be compared to the 46 dBm/100 MHz taken in the previous
version of this paper.
2.2
Earth exploration service (NGSO)
2.2.1
Assumptions
The sharing criteria are given in Recommendation ITU-R SA.1027 which latest version has been
approved at Study Group 7 in April.
The long-term protection criterion is a received power of -143 dBW/10 MHz not to be exceeded
more than 20% of the visibility (or contact) time. The short-term criterion is a received power of 116 dBW/10 MHz not to be exceeded more than 0.005% of the visibility (or contact) time.
The protection distances calculations take into account both criteria. The distance retained in
each azimuth represents the maximum of the one obtained using the short-term criterion and the
one obtained using the long-term criterion.
The only parameters needed for the receiving earth station are the longitude, latitude, antenna
height above ground and antenna diameter or maximum gain. The antenna pattern considered to
calculate the gain towards the first obstacle or the horizon is based on RR Appendix 8. The earth
station is then assumed to point at its minimum elevation angle.
2
2.2.2
DLR earth station in Weilheim (Germany)
Parameter
Value
Longitude
11.0810°E
Latitude
47.8815°N
Antenna height
17.1 m
Maximum antenna gain
69.4 dBi
The maximum separation distance is in the order of 65km, expanding into Austria.
2.2.3
DLR earth station in Neustrelitz (Germany)
Parameter
Value
Longitude
13.0691°E
Latitude
53.3298°N
Antenna height
9.6 m
Maximum antenna gain
68.4 dBi
The maximum separation distance is around 26 km.
3
2.2.4
German MoD earth station in Gelsdorf (Germany)
Parameter
Value
Longitude
7.0359°E
Latitude
50.5690°N
Antenna height
4.5 m
Maximum antenna gain
63.1 dBi
The maximum separation distance is around 73 km, encompassing the cities of Bonn and
Cologne.
4
2.2.5
ESA earth station in Kiruna (Sweden)
Parameter
Value
Longitude
20.9644°E
Latitude
67.8572°N
Antenna height
10 m
Maximum antenna gain
70.7 dBi
The maximum separation distance is around 55 km.
5
2.2.6
ESA earth station in Redu (Belgium)
Parameter
Value
5.1453°E
Longitude
50.0003°N
Latitude
Antenna height
7m
Maximum antenna gain
68.7 dBi
The maximum separation distance is around 14 km.
6
2.3
Earth exploration service (GSO)
2.3.1
Assumptions
The sharing criteria for EESS are given in Recommendation ITU-R SA.1161 which latest version
has been approved by Study Group 7 at its April meeting.
The long-term protection criterion is a received power of -147.7 dBW/10 MHz not to be exceeded
more than 20% of the time. The short-term criterion is a received power of -133 dBW/10 MHz not
to be exceeded more than 0.1% of the time.
The protection distances calculations take into account both criteria. The distance retained in
each azimuth represents the maximum of the one obtained using the short-term criterion and the
one obtained using the long-term criterion.
The only parameters needed for the receiving earth station are the longitude, latitude, antenna
height above ground, antenna diameter or maximum gain, and the GSO satellite longitude the
earth station is pointing at. The antenna pattern considered to calculate the gain towards the first
obstacle or the horizon is based on RR Appendix 8.
2.3.2
EUMETSAT earth station in Leuk (Switzerland)
Parameter
Value
7.6469°E
Longitude
46.3181°N
Latitude
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
0°
The maximum separation distance is around 10 km.
7
2.3.3
EUMETSAT earth station in Lario (Italy)
Parameter
Value
9.4094°E
Longitude
46.1572°N
Latitude
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
0°
The station is assumed to be pointed towards the MTG satellite at 0°E. The maximum separation
distance is around 10 km.
8
2.4
Data Relay Satellite (GSO EESS)
2.4.1
Assumptions
The protection criterion is given in Recommendation ITU-R SA.1155 which latest version has
been approved in last Study Group 7 meeting. It is a I0/N0 of -6 dB. Recommendation ITU-R
SA.1414 also under revision gives a system noise temperature of 300 K for EDRS receiving earth
stations leading to a criterion of -149.8 dBW/MHz or -139.8 dBW/10 MHz. The associated
percentage of time is 0.1% for manned and unmanned missions.
The only parameters needed for the receiving earth station are the longitude, latitude, antenna
height above ground, antenna diameter or maximum gain, and the GSO satellite longitude the
earth station is pointing at. The antenna pattern considered to calculate the gain towards the first
obstacle or the horizon is based on RR Appendix 8.
2.4.2
DLR EDRS earth station in Weilheim (Germany)
Parameter
Value
Longitude
11.0816°E
Latitude
47.8820°N
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
9°E
The station is assumed to be pointed towards the EUTELSAT-9B satellite hosting the EDRS-A
payload, at 9°E. The maximum separation distance is around 10 km.
9
2.4.3
DLR earth station in Oberpfaffenhofen (Germany)
Parameter
Value
Longitude
11.2794°E
Latitude
48.0861°N
Antenna height
20 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
25°E
The station is assumed to be pointed towards the ALPHASAT satellite at 25°E which includes a
Ka-band payload to test the technologies used for EDRS. The maximum separation distance is
around 10 km.
10
2.5
Space research service (near-Earth)
2.5.1
Assumptions
The protection criterion criteria are given in Recommendation ITU-R SA.609.
The protection criterion is a received power of -156 dBW/1 MHz not to be exceeded more than
0.1% of the time for unmanned missions such as Lagrangian missions already in operation, or
0.001% of the time for manned missions such as future lunar missions foreseen by ESA. This last
criterion is the worst case.
The only parameters needed for the receiving earth station are the longitude, latitude, antenna
height above ground and antenna diameter or maximum gain. The antenna pattern considered to
calculate the gain towards the first obstacle or the horizon is based on RR Appendix 8.
2.5.2
ESA SRS Earth station in Redu (Belgium - unmanned missions)
Parameter
Value
5.1453°E
Longitude
50.0003°N
Latitude
Antenna height
7m
Maximum antenna gain
68.7 dBi
The maximum separation distance is around 15 km.
11
2.5.3
ESA SRS Earth station in Redu (Belgium - manned missions)
Parameter
Value
5.1453°E
Longitude
50.0003°N
Latitude
Antenna height
7m
Maximum antenna gain
68.7 dBi
The maximum separation distance is around 27 km.
12
2.5.4
ESA SRS Earth station in Cebreros (Spain - manned and unmanned missions)
Parameter
Value
Longitude
4.3676°W
Latitude
40.4527°N
Antenna height
21 m
Maximum antenna gain
78 dBi
The maximum separation distance is around 30 km. For such low distances there is little
difference between the 0.1% and 0.001% cases.
13
2.5.5
NASA SRS Earth station in Robledo (Spain - unmanned missions)
Parameter
Value
Longitude
4.2508°W
Latitude
40.4275°N
Antenna height
21 m
Maximum antenna gain
78 dBi
The maximum separation distance is around 91 km.
14
2.5.6
NASA SRS Earth station in Robledo (Spain - manned missions)
Parameter
Value
Longitude
4.2508°W
Latitude
40.4275°N
Antenna height
21 m
Maximum antenna gain
78 dBi
The maximum separation distance is around 104 km.
15
3
Single user equipment static analysis (Scenario 1b)
The user equipment antenna height is assumed to be 1.5 m. Its antenna panel is assumed to be
pointing in the same azimuth as the victim earth station.
The UE input power is 10 dBm per element, or 22 dBm total, with an ohmic loss of 3 dB and a
maximum antenna gain of 17 dBi leading to a maximum EIRP of 36 dBm. The associated
bandwidth is 200 MHz. An additional body loss of 4 dB is also taken into account.
Recommendation ITU-R M2101 developed by WP 5D provides an antenna pattern model for both
the BS and UE. The UE antenna consists in 4 x 4 elements. No antenna discrimination was
assumed in this worst case study since when a UE is at 300 m from a 15m height BS the elevation
angle is close to 0°.
No additional cross polarization attenuation has been accounted for.
The overall maximum EIRP towards the horizon is therefore 36-4 dBi = 32 dBm in 200 MHz or 29
dBm/100 MHz. This has to be compared to the EIRP of 47 dBm/200 MHz or 44 dBm/100 MHz
taken in section 2. This associated to a lower antenna height in clutter will lead to worst case
separation distances that can only be lower than the ones found in section 2.
4
Single cell static analysis (Scenario 1c)
In this scenario it would be necessary to account for the TDD scheme. In a given cell there can
only be one transmitter, either a BS or a UE at one moment in time (To be confirmed taking into
account the possibility of several beams at the same moment in time).
Because of this, the worst separation distances for a single cell would be lower than the ones
found in section 2.
16
5
Single base station dynamic analysis (Scenario 2)
Since the base station is in fact tracking a UE and the victim earth station tracking either a GSO
or NGSO spacecraft, the worst case which was the basis of the analysis in section 2 only happens
for very low percentages of time. The movements of the antennas and variations in the
propagation loss need to be taken into account to determine a more realistic contour that would
allow to meet both the short-term and long-term protection criteria.
It should be noted that those results should be considered as preliminary only given the
uncertainties on the cell ranges and multi beam possibilities which have not been
documented in the liaison statement from WP 5D.
5.1
Methodology
A modified version of the Time Variable Gain (TVG) methodology given in Annex 6 of Appendix
7 of the RR was used to approximate the convolution of the distributions of the transmitter antenna
gain (base station tracking the UE), the receiver antenna gain (the EESS earth station tracking
an EESS satellite on a typical polar orbit or a SRS earth station tracking the moon or a Lagrange
point), and the propagation model.
The interference level that would be created at the antenna port of an EESS/SRS/METSAT/ISS
earth station is the sum (or difference) of 3 different independant random variables which are the
base station antenna gain, the EESS/SRS/METSAT/ISS antenna gain, and the propagation loss:
𝐼(𝑝) = 𝑃𝑡 + 𝐺𝑡 (𝑝𝑡 ) + 𝐺𝑟 (𝑝𝑟 ) − 𝐿(𝑝𝑣 )
It should be noted that the transmission power itself could be considered as a fourth random
variable, in particular when a User Equipment with power control is considered instead of an IMT
base station. However in this case there may be a relationship between the transmission power
and the transmitter antenna gain that are no longer independant. This has not been considered
in this study.
This equation can be simplified by:
𝐼(𝑝) = 𝑃𝑡 + 𝐺𝑐 (𝑝𝑣 ) − 𝐿(𝑝𝑣 )
Where Gc would be the composite gain Gt+Gr which distribution is the convolution of Gt and Gr
distributions. Once this distribution si known, one can derive the propagation loss and associated
percentage of time associated with the propagation model using these equation:
𝐿(𝑝𝑣 ) = 𝑃𝑡 + 𝐺𝑐 (𝑝𝑣 ) − 𝐼(𝑝)
 100 p / pn

pν  
 50

for pn  2 p
%
for pn  2 p
The limitation to 50% comes from the propagation model used, Recommendation P.452, which
is limited to percentages of time up to 50%.
Once the propagation loss is known the associated separation distance can be determined.
The difficulty comes from the fact that, for each azimuth around the victim earth station, this
calculation has to be performed for all values of the composite gain Gc with a given step, and
their associated percentage of time pv. The separation distance required would then be the
maximum separation distance obtained. For each victim earth station, this required up to 360 x
1000 calculations of distances using P.452.
In order to validate the methodology, an additional conventional Monte Carlo simulation was
performed to verify that some of the points of the contours obtained indeed just meet the short
and long-term criteria for EESS/SRS/METSAT and ISS. Performing a TVG calculation for the
long-term has shown that the obtained separation distance was giving an unnecessary
17
additional margin of 20 to 30 dB with regard to both criteria, while the separation distances were
over estimated, sometimes by a factor of 10. The TVG methodology, which has been designed
originately for coordination involving only a short-term criterion, can therefore not be used o
assess the compliance with a long-term criterion. This Monte Carlo simulation also showed that
if the short-term protection criterion was met, the long-term would also be met. Hence the TVG
calculation was only performed for the short-term.
As an example, the following contour has been determined for the EUMETSAT earth station in
Leuk (Switserland) tracking a METSAT satellite at 0° longitude, using the TVG methodology.
The satellite is located South West of the station which explains the increase of the separation
distance in this direction, due to less antenna discrimination.
The two following curves give the results of Monte Carlo simulations for the azimuth 68° in the
contour above (yellow line), which separation distance has been determined to be 1.7 km. The
first curve gives the result of the Monte Carlo simulation for the point at 1.7 km distance, and the
second one gives the result of the Monte Carlo simulation for the point at 1.6 km, in this
azimuth. In the first case both criteria are largely met, while they are slightly exceeded in the
18
second case
Several tens of such verifications have been done for all possible cases, GSO, NGSO, EESS,
SRS, METSAT or ISS in order to validate the contours obtained.
It can be seen in the following sections, that the separation distances obtained are drastically
reduced compared to the so called static studies in section 2.
5.2
5G parameters
The base station parameters are similar to the ones taken in scenario 1a.
In this case the antenna beam is tracking a User Equipment (This still has to be confirmed) in the
sector. A uniform random distribution in azimuth and a uniform distribution in distance from 0 to
300m from the base station has been assumed. This leads to the following distribution in the
beam elevation.
19
From this an the uniform distribution in azimuth it is possible to determine the antenna gain
distribution towards the victim earth station, using the antenna pattern from recommendation ITUR M.2101 applied to a 8x8 elements antenna.
A 80% TDD factor has also been taken into account.
For an antenna height of 15 m in suburban open space environment, which clutter height would
be 9m, there would be no clutter loss. The separation distance for a base station at 6m height in
clutter is given in another section at the end of this document.
5.3
Earth exploration service (NGSO)
5.3.1
Assumptions
The characteristics of the EESS earth station are similar to the ones taken in section 2.2.
This time the antenna is assumed to be tracking an EESS satellite on a polar orbit at 750 km
altitude. The distribution of azimuth and elevation pointing angles cannot therefore be considered
uniform and will depend on the latitude of the earth station. It has been determined using the STK
software and is given in the next two figures for an earth station located in Germany.
20
The antenna gain distribution towards the base station will depend on azimuth of this base station
as seen from the EESS earth station and is given in the following figure for a particular one.
21
5.3.2
DLR earth station in Weilheim (Germany)
Parameter
Value
Longitude
11.0810°E
Latitude
47.8815°N
Antenna height
17.1 m
Maximum antenna gain
69.4 dBi
The maximum separation distance is in the order of 3.8 km.
22
5.3.3
DLR earth station in Neustrelitz (Germany)
Parameter
Value
Longitude
13.0691°E
Latitude
53.3298°N
Antenna height
9.6 m
Maximum antenna gain
68.4 dBi
The maximum separation distance is around 3.8 km.
5.3.4
German MoD earth station in Gelsdorf (Germany)
Parameter
Value
Longitude
7.0359°E
Latitude
50.5690°N
Antenna height
4.5 m
Maximum antenna gain
63.1 dBi
The maximum separation distance is around 3.9 km.
23
5.3.5
ESA earth station in Kiruna (Sweden)
Parameter
Value
Longitude
20.9644°E
Latitude
67.8572°N
Antenna height
10 m
Maximum antenna gain
70.7 dBi
The maximum separation distance is around 3.7 km.
24
5.3.6
ESA earth station in Redu (Belgium)
Parameter
Value
5.1453°E
Longitude
50.0003°N
Latitude
Antenna height
7m
Maximum antenna gain
68.7 dBi
The maximum separation distance is around 3.6 km.
25
5.4
Earth exploration service (GSO)
5.4.1
Assumptions
The characteristics are similar to the ones in section 2.3. The antenna is pointing in a fixed
direction towards a GSO satellite and the gain towards the base station does not vary in time.
5.4.2
EUMETSAT earth station in Leuk (Switzerland)
Parameter
Value
7.6469°E
Longitude
46.3181°N
Latitude
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
0°
The maximum separation distance is around 3 km.
26
5.4.3
EUMETSAT earth station in Lario (Italy)
Parameter
Value
9.4094°E
Longitude
46.1572°N
Latitude
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
0°
The station is assumed to be pointed towards the MTG satellite at 0°E. The maximum separation
distance is around 2.6 km.
27
5.5
Data Relay Satellite (GSO EESS)
5.5.1
Assumptions
The characteristics are similar to the ones in section 2.4. The antenna is pointing in a fixed
direction towards a GSO satellite and the gain towards the base station does not vary in time.
5.5.2
DLR EDRS earth station in Weilheim (Germany)
Parameter
Value
Longitude
11.0816°E
Latitude
47.8820°N
Antenna height
4.7 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
9°E
The station is assumed to be pointed towards the EUTELSAT-9B satellite hosting the EDRS-A
payload, at 9°E. The maximum separation distance is around 6.5 km.
28
5.5.3
DLR earth station in Oberpfaffenhofen (Germany)
Parameter
Value
Longitude
11.2794°E
Latitude
48.0861°N
Antenna height
20 m
Maximum antenna gain
63.4 dBi
GSO satellite longitude
25°E
The station is assumed to be pointed towards the ALPHASAT satellite at 25°E which includes a
Ka-band payload to test the technologies used for EDRS. The maximum separation distance is
around 6.8 km.
29
5.6
Space research service (near-Earth)
5.6.1
Assumptions
The characteristics are similar to the ones in section 2.5.
The SRS earth station antenna is moving, tracking an SRS spacecraft. For SRS, different types
of orbits are possible, from LEO to Lagrangian missions. In this document, the SRS earth stations
have been assumed to track a Lunar mission, which could be manned missions in the future, and
therefore point towards the Moon. Further work would be required to analyse the impact of other
types of missions.
The azimuth and elevation angles distribution is given in the following figures for the Cebreros
station in Spain.
30
5.6.2
ESA SRS Earth station in Redu (Belgium – manned and unmanned missions)
Parameter
Value
5.1453°E
Longitude
50.0003°N
Latitude
Antenna height
7m
Maximum antenna gain
68.7 dBi
The maximum separation distance is around 7.5 km.
31
5.6.3
ESA SRS Earth station in Cebreros (Spain - manned and unmanned missions)
Parameter
Value
Longitude
4.3676°W
Latitude
40.4527°N
Antenna height
21 m
Maximum antenna gain
78 dBi
The maximum separation distance is around 24 km.
5.6.4
NASA SRS Earth station in Robledo (Spain – manned and unmanned missions)
Parameter
Value
Longitude
4.2508°W
Latitude
40.4275°N
Antenna height
21 m
Maximum antenna gain
78 dBi
The maximum separation distance is around 14 km.
32
6
Discussion on the validity of the results for scenario 2 found in
section 5
6.1
Consideration of other BS eirps
The results obtained in the previous sections and in particular in section 5 take into account a
base station in suburban open space environment with an eirp of 48 dBm. It should be noted that
higher eirp up to 75 dBm are still under discussion in other fora. The consideration of a 75 dBm
eirp would lead to a separation distance multiplied by 10 for the example of Gelsdorf as shown in
the following figure (maximum distance 38 km for the empty contour to be compared to 3.5 km
for the 48 dBm eirp in the filled contour). The eirp of the base station should therefore be limited
to 48 dBm through relevant regulation to ensure such separation distances are not exceeded.
33
6.2
Consideration of multiple beams
In the case of multiple beam forming using only part of the BS antenna panel (e.g. 4 beams with
4 x 4 elements each) on one single frequency, the antenna gain of those beams and hence the
antenna discrimination towards the horizon, would be lower. This combined with the possibility of
4 simultaneous beams would change the results.
6.3
Consideration of BS in urban environment
In the case of a base station in urban environment, the contour would be reduced due to 3 effects:
-
The antenna height is reduced to 6m;
The clutter needs to be taken into account;
The maximum cell range would reduce.
The following curve gives the clutter distribution at 3 km using the clutter model developed by
SG3 in the PDNR ITU-R P.[CLUTTER].
34
It can be seen that while the median value is at 37 dB, the clutter loss would be limited to 20 dB
for few of the BS locations. Since we are addressing a single BS in this document, the value of
20 dB has been considered. This reduces to 15 dB for a separation distance of 0.5 km instead of
3 km.
A cell range of 100 m has been provisionally adopted.
With these assumptions the separation distance for Gelsdorf would reduce to 0.7 km.
7
Conclusions
The analyses in this document provide the calculation distances around a number of
EESS/SRS/ISS/METSAT earth stations locations within Europe, using a fixed antenna gain for
both the interfering and victim station, but also considering the variation of the antenna gain
towards the horizon for both the interfering and victim stations. This last scenario leads to
separation distances which are much shorter, but needs to be refined after all detailed parameters
such as the multiple beams, maximum cell range and distribution of UE within this cell, … have
been determined and agreed upon.
35