Optimisation de la gestion des ressources voie...
Transcript of Optimisation de la gestion des ressources voie...
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
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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
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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
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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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