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Optimisation de la gestion des ressources voieretour
Yoann Couble1,2,3,4, Emmanuel Chaput2, Thibault Deleu3,Cedric Baudoin3, Jean-Baptiste Dupe4, Caroline Bes4 and
Andre-Luc Beylot2
1TeSA 2IRIT, 3TAS, 4CNES
June 12, 2017
Optim. Interf. RL 2017/06/12 Couble Y. TAS, CNES, IRIT, TeSA 1/26
Agenda
La voie RetourDVB-RCS2: Acces dedieBilan de liaison voie retour
Gestion des Interferences4 couleurs2 couleurs
Papier ICCLitteratureModeleResultatsAutres contributions
Conclusion
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Context of Satellite Uplink scheduling
Gateway
Geosta�onnary
Mul�-Beam Satellite
(Transparent)
User terminal
(RCST)
RHCPbeams
LHCPbeams
Q/V
bands
Ka/Kubands
Internet
Figure: System Architecture
I Satellite transparent geostationnaireI Antennes multi-faiseaux et Gateway centralisee
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La voie Retour
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Protocoles de la voie retour (Acces)
Time
Frequency
Ded
icat
ed A
cces
sA
vail
able
Spe
ctru
m
Frame Duration
carrier
...
Random Access Channel
MF-TDMAFrame
Figure: Example of MF-TDMA Frame
DVB-RCS2:
I Canaux a acces aleatoire: CRDSAet autres.
I Canaux a acces dedie:I Demand Assigned Multiple
Access (DAMA)I Multiple Frequency Time Division
Multiple Access (MF-TDMA)
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Principes du DAMA
Gateway
DAMA Req. (VDBC, RDBC, CRA) via RA/DA
DAMA Req. (VDBC, RDBC, CRA) via RA/DA
UT1
UT2
GEO Sat
UT
1
UT
2
UT
3
UT
4
UT
5U
T6
UT
7
cumulated req.
DAMA Manager
Scheduler
freq
timeTB
TP
2Gateway
TBTP2 (broadcast)
1
1
2
3
4
Gateway
Transmission on dedicated slotsUT1
UT2
5freq
time
freq
time
Transmission on dedicated slots5Internet
Figure: Schematic DAMA process
Optim. Interf. RL 2017/06/12 Couble Y. TAS, CNES, IRIT, TeSA 6/26
Hypotheses
Frequen
cy
TimePow
er
16QAM - 5/6
8PSK - 5/6
8PSK - 3/4QPSK - 5/6QPSK - 1/3
Figure: An example of MF-TDMA Frame,with various MODCOD in different slots.
Hypotheses:
I Porteuses a Rs egal
I Une seule taille de BTU (1616symboles)
I MODCOD selection just-in-time
Autres caracteristiques du systemeconsidere:
I 2 polarisations (RHCP, LHCP)
I NC porteuses de 21MHz (BATS)
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Bilan de liaison voie retour - Attenuation angulaire
-600 -300 0 +300Distance from beam k center (km)
Gain
att
en
uati
on
for
beam
k (
dB
)
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
-480
-360
-240
-120
0
+120
+240
+360
+480
+600
Dis
tance
fro
m b
eam
k c
ente
r (k
m)
+600
Figure: Attenuation en fonction de la distance au centre du beam
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Bilan de liaison voie retour - Remarques
beamdire
ctivity
α1,a
α3,a
α2,a
Beam a Rx:P1Ga(α1,a) + P2Ga(α2,a) + P3Ga(α3,a)
BEAM a BEAM cBEAM b
RCST 1
RCST 3RCST 2tra
nsmitte
d signal
Figure: Principe des interferences voie retour
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Bilan de liaison voie retour - FL vs. RL
reciev
ed s
igna
ls
BEAM a BEAM c
BEAM bRCST 1 RCST 3
RCST 2
RCST 1 Rx:
α1,b
α1,cα1,a
beam directivity
PaGa(α1,a) + PbGb(α1,b) + PcGc(α1,c)
Figure: Principe des interferences voie aller
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Gestion des Interferences
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4 coloration - principes
RHCP
LHCP
RHCP
LHCP
RHCP
LHCP
RHCP
LHCP
RHCP
LHCP
Figure: Exemple de coloration a 4 couleurs
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Coloration - Feeder Link
user linksfeeder linkRHCP
LHCP
RHCP
LHCP
RHCP
LHCP
Figure: Bande Necessaire Feeder Link
I Pour un taux de reutilisation de frequence de 1/4, il fautNbeams × Bande × 2× 1/4 de bande disponible sur le feederlink
I Grande importance de l’efficacite en bande passante!
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Augmenter le debit d’un beam?
I Augmenter la bande de chaque couleur, enrestant en 4 couleurs⇒ Bande limitee
I Autre alternative: Ameliorer la directivite desantennes, et reduire la taille des beams
I Augmenter le taux de reutilisation defrequences
I Interferences preponderantes!I Densifie l’utilisation des frequencesI Inevitable a long terme
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Coloration a 2 couleurs
RHCP
LHCP
RHCP
LHCP
RHCP
LHCP
freq
timeRHCP
TBTP2
LHCP
TBTP2
freq
time
freq
timeRHCP
TBTP2
LHCP
TBTP2
freq
time
Figure: Schema de coloration a deux couleurs sur maille hexagonale
I Interferences tres fortes sur les beams voisins
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Solutions classiques
I Decentralise + ACM → Aucune correlation apriori entre un slot et le suivant.
I Decentralise + Estimation d’interference→ Trop de pertes et de MODCODsous-optimaux
Explication: Interference trop variable d’un interferent a l’autre.Solution: Coordination individuelle d’interference
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Exemple - Scenario
freq
time
freq
time
freq
time
1
2
3
4
5
6 78
9 10
1112
13
Figure: Scenario simpliste - Les couleurs correspondent aux utilisateursordonnances sur la meme ressource
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Exemple - Scenario
freq
time
freq
time
freq
time
1
2
3
4
5
6 78
9 10
1112
13
Low interferenceVery high
interferenceHighinterference
BAD INTERFERING SET !!
Figure: Scenario simpliste - Les couleurs correspondent aux utilisateursordonnances sur la meme ressource
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Exemple - Scenario
freq
time
freq
time
freq
time
1
2
3
4
5
6 78
9 10
1112
13
Low interferenceHighinterference
Better
Figure: Scenario simpliste - Les couleurs correspondent aux utilisateursordonnances sur la meme ressource
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Exemple - Scenario
freq
time
freq
time
freq
time
1
2
3
4
5
6 78
9 10
1112
13
Low interference
GOOD INTERFERING SET !!
Figure: Scenario simpliste - Les couleurs correspondent aux utilisateursordonnances sur la meme ressource
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Papier ICC
Optim. Interf. RL 2017/06/12 Couble Y. TAS, CNES, IRIT, TeSA 18/26
Objectifs et Focus de modelisation
Objectifs:
I Determiner la Capacite maximale d’un scenario
I Sur des Scenario de grande taille (Cumul d’interference)
Focus de modelisation:
I Permettre une non-allocation
I Jouer sur les MODCODS
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Architecture - Centralized scheduling
Physical Gateways
CentralizedScheduler
freq
time
freq
time
TBTP2 - Beam A
freq
time
TBTP2 - Beam B
TBTP2 - Beam C
Joint Scheduling
freq
time
freq
time
freq
time
freq
timefreq
time
freq
time
freq
time
freq
time
freq
time
Beam A
Beam B
Beam C
Figure: Centralized scheduling, with TBTP2 propagation
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Modele: Probleme complet
Sum-rate Maximization Objective
1 user per Resource Block
Users are limited to 1 carrier for each timeslot
Discretized SNIR Constraint
Decision variable for user ik of beam k MCS m, for RB (t,c)
Figure: Modele: Probleme complet
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Resultats
Charge de la trame: Ncarrier/Nusers
Cap
acit
é m
ax d
u sy
stèm
e (N
orm
alis
é)
100%
108%
145%
160%
0.5 1.0 2.0
2 couleurs: Optimal
4 couleurs non coordonné2 couleurs non coordonné
~63%~61%
~48%
← Figure: Resultats moyens, 2couleurs coordonne vs. 4 couleursnon coordonne. Resultats pour18 beams, 8 porteuses, 4/8/16utilisateurs par beam.
I Resolu avec Gurobi
I Plus il y a d’utilisateurs, plusla capacite max est grande
I Temps de resolution tresimportants
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Autres contributions et resultats
I Simplifications:I Decomposition par porteuseI Importance des voisins
I Resultats: Meilleurs temps de calculs, perted’optimalite minime (max 4% pour des chargesimportantes).
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Conclusion
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I Outil generique:I Calcul de capacite maximale d’un schema de
coloration (pour un scenario donne)I Adaptable a d’autres maillagesI Adaptable a la voie allerI Base de comparaison pour des algorithmes plus
rapides
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Questions ?
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Bibliographie
I Yoann Couble et al. “Interference-aware Frame Optimization for the Return Link of a Multi-Beam Satellite(regular paper)”. In: IEEE International Conference on Communications (IEEE ICC). 2017
I K. Kiatmanaroj. “Allocation de frequence dans les systemes de communication par satellites de typeSDMA”. . These. 2012
I Arie Koster. Frequency Assignment - Models and Algorithms. 1999I Ui Yi Ng, Argyrios Kyrgiazos, and Barry Evans. “Interference coordination for the return link of a
multibeam satellite system”. In: Advanced Satellite Multimedia Systems Conference and the 13th SignalProcessing for Space Communications Workshop (ASMS/SPSC), 2014 7th. IEEE. 2014
I V. Boussemart, M. Berioli, and F. Rossetto. “User scheduling for large multi-beam satellite MIMOsystems”. In: 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems andComputers (ASILOMAR). 2011
I Valeria D’Amico and Jochen Giese. ARTIST4G: Innovative scheduling and cross-layer design techniques forinterference avoidance. Tech. rep. 2012
I Raymond Kwan and Cyril Leung. “A Survey of Scheduling and Interference Mitigation in LTE”. . In: JECE2010 (2010). url: http://dx.doi.org/10.1155/2010/273486
I S. Dimitrov et al. “Radio resource management techniques for high throughput satellite communicationsystems”. In: 2015 European Conference on Networks and Communications (EuCNC). 2015
I G. Cocco et al. “Radio resource management strategies for DVB-S2 systems operated with flexible satellitepayloads”. In: 2016 8th Advanced Satellite Multimedia Systems Conference and the 14th SignalProcessing for Space Communications Workshop (ASMS/SPSC). 2016
I ETSI. “EN301 545-2 v1.2.1: Second Generation DVB Interactive Satellite System (DVB-RCS2)”. In:2012
I ETSI. “TR101 545-4 v1.1.1: Second Generation DVB Interactive Satellite System (DVB-RCS2); Part 4Guidelines for Implementation and Use of EN301 545-2”. In: 2014
I Inc. Gurobi Optimization. Gurobi Optimizer Reference Manual. 2016. url: http://www.gurobi.comI S. Cioni, R. De Gaudenzi, and R. Rinaldo. “Adaptive coding and modulation for the forward link of
broadband satellite networks”. In: IEEE GLOBECOM. vol. 6. 2003I BATS Project. D4.5.1 - Overall Strategy and Algorithms for Interference Management. 2015I Michael Schneider, Christian Hartwanger, and Helmut Wolf. “Antennas for multiple spot beam satellites”.
In: CEAS Space Journal 2.1 (2011)
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Bilan de liaison voie retour - Attenuation angulaire
-600 -300 0 +300Distance from beam k center (km)
Gain
att
en
uati
on
for
beam
k (
dB
)
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
-480
-360
-240
-120
0
+120
+240
+360
+480
+600
Dis
tance
fro
m b
eam
k c
ente
r (k
m)
+600
Figure: Attenuation en fonction de la distance au centre du beam
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Bilan de liaison voie retour: SNIR
Reception Gain of the k-th beam for user ik
User ik transmissionpower
Noise power(same for each c)
Indicator of user jk'assigned to RB (t,c)
Figure: Formule du bilan de liaison (simplifie)I Gk(ik) comprend tout type d’attenuation (angulaire, FSL,
atmo. ...) ainsi que tous les autres parametres constants dubilan de liaison
I N integre aussi l’interference Cross-Polarisation etInter-Canaux (consideres comme du AWGN)
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