Post on 06-Apr-2020
ESA UNCLASSIFIED - For Official Use
Co-existence of GSO and NGSO HTS systems :
technical considerations
Damien ROQUES
16/10/2017
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 2
Broadband systems in FSS bands - GSO (geostationary) “GEO-HTS” systems :
- HTS, multi-beam systems in Ku and Ka band
- 3 Millions consumers worldwide (Euroconsult)
- Example : Eutelsat Ka-Sat, Intelsat Epic, Echostar, Viasat…
- Upcoming NGSO (non-geostationary) “LEO-HTS” broadband systems :
- Constellations of 10s, 100s, 1000s of satellites
- At various stages of maturity
- ESA supports NGSO SATCOM constellations through its ARTES programme, and in particular addresses interference and regulation issues
Summary of broadband systems filed to the FCC in Ku/Ka band in Nov. 2016
ONEWEB TELESAT LEOSAT SPACEX O3B BOEING KEPLER VIASAT SPACE NORWAY
NB Satellites (total) 720 117 108 4425 60 60 140 24 2
Orbit TYPE LEO LEO LEO LEO MEO >25000 kms LEO MEO HEO
Band Ku/Ka Ka Ka Ku/Ka Ka Ka Ku Ka Ku/Ka
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 3
ESA scope of activities
- Sharing frequency resource among broadband systems :
- is an issue of high technical complexity, involving sophisticated regulations
- requires the elaboration of adequate technical solutions
- Under ARTES Future Preparation, part of effort focused on NGSO Interference and Regulations :
• Investigate the issue of Interference between NGSOs and GSOs, as well as between different NGSOs hypothetically sharing the same bands
• Investigate interference mitigation techniques and analyse their impact on the system throughput
• In order to achieve such objectives, an End to End software simulator for assessing performances of Mega Constellations was developed internally.
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 4
How can systems work technically ?
Coordination between GSO systems: - Static geometry - Based on “long term” interference ITU Reco. S.1323 : ∆𝑇
𝑇< 6%
GEO
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 5
How can systems work technically ?
Coordination with NGSO systems - Dynamic geometry - based on “short term” interference
ITU Reco. S.1323 :
𝑎𝑣𝑎𝑣𝑣𝑎𝑣𝑣𝑣𝑣𝑣𝑣 𝑑𝑑𝑑𝑑𝑎𝑑𝑎𝑣𝑣𝑑𝑑 𝑐𝑑𝑐𝑣𝑑𝑑 𝑓𝑑𝑑𝑐 𝑁𝑁𝑁𝑁 𝑠𝑣𝑠𝑣𝑑𝑐𝑠 < 10 %
EPFD limits to respect
- Case # 1 : NGSO / GSO coordination - NGSO GSO EPFD Limits (uplink and downlink) protecting GSO arc
?
- Case # 2 : NGSO / NGSO coordination No framework derived from recommendation
No regulation protection
- GSO NGSO NGSO systems are not protected by regulation
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 6
LEOSIM :
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 7
LEOSIM System simulator : Interference analysis module
Objective :
• quantification of impact : • of NGSO system EPFD limit levels • of GSO systems interferences on NGSO services
• impact on NGSO mission (capacity / coverage)
Impac
t of
inte
rfer
ence
on t
raffic
with a
nd
withou
t m
itig
atio
n t
echniq
ues
NGSO – GSO interference NGSO – NGSO Interference
Objective :
• estimation of frequency of interference events
• simulation of mitigation techniques • impact on NGSO mission (capacity / coverage)
Min
imum
sep
arat
ion a
ngle
in d
egre
es,
for
a giv
en inst
ant
of t
ime,
bet
wee
n 2
con
stel
lation
s
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 8
How can systems work technically
Key interrogations :
- Case #1 : NGSO – GSO coordination : - Interference from NGSO into GSO :
- Respect of EPFD limits ?
- Interference from GSO into NGSO : - Service availability without regulation
protection ?
- Case #2 : NGSO – NGSO coordination
- Best way to coordinate under current regulation ?
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 9
Case #1 : NGSO - GSO coordination
- Questions raised :
- Can new systems, with hundreds of satellite, adapt to current regulations ?
- What are the constraints involved, and the potential losses of capacity / coverage ?
- Simulations realised :
- On a constellation typ. involving hundreds of satellites, with static coverage
- Assessment of EPFD downlink statistic over Earth
- Investigation of mitigation technique for reaching ITU’s EPFD requirements
- Assessment of potential impact on NGSO system service, taking into account realistic user distribution
- Assessment of impact, from the emissions of GSO systems into the NGSO.
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 10
Results of the GSO/NGSO simulation realised
- Current EPFD limits are met with mitigation techniques
• Some marginal non compliance in our (not optimised) simulation
• Mitigation techniques involve realisable operations
- Impact on overall system capacity is limited
• Maintain of a global coverage • Overall throughput difference
rather small • Interference fom GSO into NGSO
needs to be taken into account
-200 -195 -190 -185 -180 -175 -170 -165 -160 -155 -150
epfd Down [dBW/m2 /40kHz]
10 -6
10 -5
10 -4
10 -3
10 -2
10 -1
10 0
Prob
abilit
y th
at E
PFD
is ex
ceed
ed
EPFD Downlink UT 60 cm
ARTICLE 22 Mask
Results - all locations
Results - WCG
Results - LEOSIM Worst Case
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 11
Case #2 : NGSO – NGSO coordination
- Recall : reco S.1323 : maximum availability degradation from NGSO system interference shall not exceed 10%
- FCC has proposed a methodology, based on taking into account in-line events :
- an in line event happens when 2 satellites get physically aligned from a user location point of view, i.e. the angle difference becomes too small to separate them
- Main questions :
- What is the size of the angle ?
- What is the rule applied when an in line event occurs ?
- What needs to be shared between operators to compute in line events ?
Angle difference 1
1 : See FCC notice of proposed rulemaking, DA # 16-170
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 12
minimum angle separation seen on ground between 2 different constellations
LEOSIM SAMPLE OUTPUTS NGSO/NGSO Coordination
Uncoordinated operations Coordinated operations Conclusions - Without sufficient sharing of information, evaluation of interference events is quite pessimistic - Size of the separation angle needs to be carefully determined - In coordinated operations, mutual level of interference is mitigated and impact on capacity (on a global
scale) is limited.
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 13
LEOSIM – NGSO/NGSO coordination comparison of different angles for in-line events
Minimum angle = 10 degrees Minimum angle = 5 degrees Trigger based on ∆T/T
Visualisation of percentage of satellites involved in in-line events, depending on angle defined
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 14
Conclusions
- NGSO systems coordination is a major challenge, to address for an efficient use of spectrum bandwidth
- ESA presented a fully functional system SW for interference analysis - Estimation of interference and mitigation techniques - Analysis of consequences on the service
- First results are promising, although a lot of work remaining
- Interference framework towards GSO systems can be respected - Promising leads shall be investigated for NGSO-NGSO coordination
ESA UNCLASSIFIED - For Official Use Roques, Damien | 02/10/2017 | Slide 15
Next steps - Future enhancements of developed simulator
- Uplink computations - Integration of steerable beams for capacity computing
- Industry oriented activities initiated
• ARTES 3A.087 : Simulator for Managing Interference Between NGSO Constellations and GSO • Initiated : See EMITS AO 8919 • To validate our results, add new functionalities, enhance performances
• ARTES 3A.095 : Flexible resource allocation techniques for NGSO constellations
• pending approval - to be initiated in 2018
- ESA welcomes any feedback from interested parties ! - Contacts :
• Emiliano RE (emiliano.re@esa.int) • Damien ROQUES (damien.roques@esa.int)
Slide Number 1Broadband systems in FSS bandsESA scope of activitiesHow can systems work technically ?How can systems work technically ?Slide Number 6LEOSIM System simulator : Interference analysis moduleHow can systems work technicallyCase #1 : NGSO - GSO coordinationResults of the GSO/NGSO simulation realisedCase #2 : NGSO – NGSO coordinationSlide Number 12LEOSIM – NGSO/NGSO coordination�comparison of different angles for in-line eventsConclusionsNext steps