SDLS
(Satellite Data Link System)
SYSTEM PRESENTATION
ICAO ACP Working Group C - Toulouse October 2003
ACP WGC6/WP19
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PRESENTATION PLAN
 PART I - INTRODUCTION & CONTEXT
 PART II - SDLS SYSTEM DESIGN PRESENTATION
 PART III - PROJECT STATUS AND WAY FORWARD
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PART I - INTRODUCTION & CONTEXT
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SDLS a CANDIDATE to NEXSAT INITIATIVE
The European Space Agency
and Eurocontrol are
co-ordinating their effort
An Agreement of Co-operation has been signed and one task is to progress the
definition of a Next Generation Satellite System
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SDLS AND NEXSAT CONTRIBUTIONS
 Eurocontrol and ESA associate their effort to develop a New
Generation Aeronautical Satellite System
t
NextSa
Slice
1
Slice
2
Slice
3
SDLS
System t
pmen
Develo
System
ment
Deploy
System
on
Operati
Eurocontrol contribution
ESA contribution
States, EC, Operators
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SDLS MISSIONS
 SDLS Definition
SDLS is as a potential Next Generation Aeronautical Communication System
 SDLS Missions
as specified in Eurocontrol Mission Requirement Document, in line with
Nexsat initiative

Complement the VHF communication system in Europe

Support datalink applications deployment in dense Airspace
World-wide coverage / Regional deployment capabilities

Supports communications needs on remote and oceanic airspace

Interoperable / Open architecture
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SDLS GENERAL CONCEPT
 Safety dedicated system (ATS and AOC communication)
Operation in protected radio-spectrum band ( L-band AMS(R)S )
Network security through clearly segregated system
Controlled network with Guaranteed Performances
 Low cost infrastructure and operational cost
Light and easy to install terminal

Omnidirectional antenna

Mono-Transmission Channel terminal

Based on up-to-date communication technology
Compatible to proven Bent-pipe Geostationary satellites
Distributed network implementation capability (reduced ground network
infrastructure)
Capability for low cost GES implementation (in Ku band)
Optimised network architecture (Spectrum efficiency)
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SDLS SERVICES
 Services supported :
ATM services (Services link2000+)
AOC services (including support of ACARS)
Critical Short data services
Voice services (Point to Point, Party Line)
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QUALITY OF SERVICE
DATA SERVICES
QoS
Application
1
Short Data
Service
2
CPDLC+
3
CPDLC
4
CPDLC-
5
ADS-C
6
ADAP
ACL
ACL,ACM, DLL,
DCL, DSC
DFIS
FLIPCY, FLIPINT,
DYNAV,COTRAC
AOC/ FANS
ACARS
5
10
30
30
30
5
Transit Delay (s)
-8
-8
-7
-6
-7
10
10
10
10
10
10-7
RER
1
1
2
3
2
2
Priority
Air> Ground Bidirectional Bidirectional Bidirectional Bidirectional Air> Ground
Direction
VOICE SERVICES
Vocoding ra te (kbps)
Communica tion Esta blishment Time (s)
Communica tion configura tion
Sa fety Voice
4.8 / 2.4
2
Point to point
Telephony
4.8 / 2.4
10
Point to point
10-3
1
10-3
2
Residual Error Ra te
Priority
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Pa rty- Line
4.8 / 2.4
Permanent
Point to
multipoint
10-3
1
SDLS HIGH LEVEL SPECIFICATIONS
Basic raw data rate 5.6kbps over dense areas (regional spot beams)
Reduced raw data rate 3.2kbps over oceanic and remote airspace (global beams)
BER : 10-5 for data, 10-3 for voice - Link availability 99.99 %
QoS management
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PART II - SDLS DESIGN PRESENTATION
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SDLS DESIGN PARADIGMS
Direct Sequence Code Division Multiple Access System (DS-CDMA)
+
Geostationary bent-pipe satellites
Advantages of this configuration :




Cancellation of Near-Far limitation of terrestrial CDMA systems
Cancellation of frequency guard bands due to AES Doppler
Cancellation of time guard with TDMA/CDMA configuration
Resistance to interference, multipath and fading (scintillation..)
Other by-products of interest :
 Supports decentralised access scheme
 Security at radio transmission level
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WAVEFORM (Results of optimisation studies)
 CDMA Access mode
Similar waveform on forward and return links
Synchronous/Quasi Synchronous CDMA scheme
 alignment spec.1/8 of a chip
 Reference carriers for synchronisation and power control
Asynchronous transmissions limited to GES and AES network entries
Modulation QPSK with pulse shaping
Spreading : Gold codes with a spread factor of 127 (BW=1MHz)
Single Data/Voice Channel Coding :
 Turbo code with rate 1/2
 Eb/No=2.6dB (256 bits blocks)
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BASIC AES CHARACTERISTICS
Design target : low cost SATCOM terminal
(i.e. similar to a VHF radio).
 Basic Terminal
Mono-transmit channel terminal with 30W HPA operated at saturation
Omnidirectional antenna (0dBi at 5°, G/T -25dB/K)
Include all the protocol stacks
Supports Arinc 429 or Arinc 664 Interfaces
 Terminal Option
AERO-I/H existing terminals supported (better EIRP-G/T figures)
Up to 22kbps (4 times basic rate) could be provided
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Current LINK BUDGET - MOBILE LINK
Uplink
EIRP
Free Space Loss
System Self-Noise1
G/ T 2
Boltzman constant
C/ N o up
Required C/ No
Data rate
Implementation Loss
Required Eb/ No (Turbocode)
Ra w Ma rgin 3
Downlink
European
Spot
Global
Spot
European
Spot
Global
Spot
15,0
-189,1
-2,0
-2,0
228,6
50,5
15,0
-189,1
-0,5
-10,0
228,6
44,0
29,0
-188,2
-2,0
-25,0
228,6
42,4
29,0
-188,2
-0,5
-25,0
228,6
43,9
dBW
dB
dB
dB/ K
dBW/ m2/ K
dB.Hz
38,1
5,6
1,0
2,6
12,4
35,6
3,2
1,0
2,6
8,4
38,1
5,6
1,0
2,6
4,3
35,6
3,2
1,0
2,6
8,3
dB.Hz
kbps
dB
dB
dB
(1)
System Self-Noise : Chip alignment and Power Control error budget with 50 co-users in regional spot and 10 users in global
spot
(2)
Conservative figures based on existing satellites and AERO-L antennas
(3)
Margin for Feeder Link contribution, Fading and Scintillation (preliminary figures : Europe -0,5 dB, Tropical regions up to -5 dB)
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Possible Data Rate Improvement on future platforms
Uplink
Downlink
MTSAT
Spot
Inmarsat IV
Wide Spot
15,0
-189,1
-2,0
-2,0
228,6
50,5
15,0
-189,1
-2,0
10,0
228,6
62,5
46,6
57,6
46,6
57,6
dB.Hz
Da ta ra te
40
500
40
500
kbps
Implementation Loss
Required Eb/ No (Turbocode)
Raw Margin
1,0
2,6
3,9
1,0
2,6
4,9
1,0
2,6
3,8
1,0
2,6
3,8
dB
dB
dB
EIRP
Free Space Loss
System Self-Noise
G/ T
Boltzman constant
C/ N o up
Required C/ No
(1)
MTSAT Inmarsat IV
Spot
Wide Spot
max 43dBW max 67dBW
37,0
48,0
-188,2
-188,2
-2,0
-2,0
-25,0
-25,0
228,6
228,6
50,4
59,4
System Self-Noise : Chip alignment and Power Control error budget with 50 co-users
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dBW
dB
dB
dB/ K
dBW/ m2/ K
dB.Hz
ACCESS - CARRIER DISTRIBUTION
Common ASYNC CDMA shared
by all AES (Spread-ALOHA).
Log-on purpose (L channel)
A Generic Distribution T CHANNEL
AES
T T T
CDMA Codes
T ... T T
n
AES1
8
Forward
CDMA
carriers
AES2
AES3
1
2
AESx
AES4
C
P and C
Dedicated Return Carriers
shared by several AES
(Except voice multiplexed
carriers)
AA
T
T
TT
AES2
AC
A Generic Distribution A CHANNEL
Ar Ad Ar Ad
...
AES1
AES2
AES3
AES3
GES
AES4
AES1
AES4
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Collision AES1
and AES3
Ar Ad
ACCESS - CARRIER DEFINITION
Data n
Data 3
Sig.
s
P
Critical Data
critical data access channel (Ad)
Critical Data Access Req.
Sig. & Short Data Packets
concurrent access channel (Ar)
Ad
Ar
A
slot allocation
Data Packets
Critical Data & Sig.
s
T
digital voice packets
critical data sub-channel
Voice
+
C
Critical Data & Sig.
Typical payloads / bursts
P, T, C : 150 bytes (Long Block Data Unit)
A :Ar : 32 bytes (Short Block Data Unit)
Ad : 8 bytes (Super Short Block Data Unit)
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Network Architecture Paradigm
End
User
Air
Router
AES
GES
Ground
Router
Optimised
Satellite Gateway
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WAN
End
User
Gateway vs. Transparent Example
Satellite Link
Optimised Interface
SDLS
Gateway
Model
7
7
6
6
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
End
User
Router
GES
AES
Router
Network Dependent
Interface
7
Transparent
Network
Model
• Protocol Overhead reduction
• Minimal retransmissions
• Channel efficiency optimisation
• Flow control
6
End
User
7
6
5
5
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
End
User
Router
GES
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End
User
QoS Management
Satellite
GES
AES
Management
Signaling
Internal Services
CPDLC high
Data 1 : Connectionless Service, QoS 2
CPDLC medium
ACL,ACM,DLL,DCL,
DSC
Data 2 : Connection Oriented Service, QoS 3
ADS-C
Provisions
FLIPCY,FLIPINT,
COTRAC,DYNAV
CPDLC high
ACL
CPDLC medium
ACL,ACM,DLL,DCL,
DSC
ADS-C
Data 3 : Connection Oriented Service, QoS 5
FLIPCY,FLIPINT,
COTRAC,DYNAV
CPDLC low +
DFIS
Data 4 : Connection Oriented Service, QoS 4
CPDLC low +
DFIS
ADAP + ADS-B
Data 5 : Connection Oriented Service, QoS 6
ADAP + ADS-B
Short Data
Service
Data 7 : Connectionless service, QoS 1
Short Data
Service
ACARS
Data 8 : Connectionless Service, QoS 4
ACARS
Telephony
Voice 1 : AOC
Telephony
Safety Voice
Voice 2 : ATS
Safety Voice
Party Line
Party Line
Voice 3 : Party Line
Offered Services
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Provisions
ACL
Supported Diversity Schemes
 SDLS Design can be instantiated with diversity schemes at several levels :
AES :

Two patch antenna to avoid masking

2Rx / 1 Tx terminal

2Rx / 2 Tx terminals
GES :

GES site diversity in Ku band the feeder links to remove rain attenuation
effect (up to 10dB)
Satellite :

Two satellites in hot redundancy
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System Expandability
 SDLS is fully scalable.
Minimal Configuration
 Operation in a single spot with one control and traffic station NMS/GES
Multi GES

Many GES can be instantiated in the system

Transparent introduction allowed by the CDMA structure of the system
Multi Frequency Slots

Expandability by steps of 500/1000KHz on the same transponder
Multi Spots

On the same satellite, several spots can be used simultaneously

Only one Network Master Station required for all spots
Multi Satellite
All system expansions are transparent to the Avionics
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PERFORMANCE FIGURES (I)
 SDLS Traffic and capacity assumptions (from Eurocontrol ref.)

Capacity assessment per aircraft
Forward link
QoS 2
Total transfered
1296
bytes
Mean message size 36
(bytes)
Message frequency 0,02
average (msg/ s)
Return link
QoS 1
Total transfered
14400
bytes
Mean message size 30
(bytes)
Message frequency 0,20
average (msg/ s)
QoS 3
QoS 4
QoS5
2957
3824
5538
41
65
180,
0,03
0,02
0,01
QoS 2
QoS 3
QoS 4
QoS5
QoS 6
1428
3106
3559
5574
36551
40
44
67
201
70
0,02
0,03
0,02
0,01
0,22
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PERFORMANCE FIGURES (II)
 Initial Simulation Results
Hypothesis & Modelling
 Queuing Analysis based on Markov models
 One GES configuration / One spot beam
 PIAC of 2000 aircrafts
Preliminary Results
FD
W
RT
P
T
4,41
Short
P
Ar
3,30
Long*
P
T
6,71
Short
P
Ar
7,65
Long*
P
T
12,29
Priority 1 (QoS1 & 2)
Priority 2 (QoS3)
Priority 3 (QoS4 & 5)
*Long packets imply to make a reservation on A channel
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Transit Delay
(sec)
<4,5 s
<7,2 s
<27 s
PERFORMANCES (III)
 Summary Table: Total number of CDMA channels (PIAC 2000 aircrafts)
Number of CDMA channels
1 GES
configuration
27
15 GES
configuration*
30
Return A channel
TBD
TBD
Return T channel
13
15
TBD
TBD
Forward P channels
Total number
*Uniform PIAC AES distribution among 15 GES
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COST FIGURES (I)
SDLS Service Unit Costs: Results for Data
System costs (Space
segment lease + GES
prices)
SDLS use-rate
Low Assumptions
Low Hyp.
Scenario
High Hyp.
Scenario
Scenario 1 (Decentralised)
Unit Costs
0.0005 € /kbit
0.0004 € /kbit
Scenario 2 (Centralised Kuband access) Unit Costs
0.0005 € /kbit
Scenario 3 (Centralised Cband access) Unit Costs
0.0005 € /kbit
High Assumptions
Low Hyp.
Scenario
0.0013 € /kbit 0.0010 € /kbit
0.34 €/flight
0.81 €/flight
0.0004 € /kbit
0.0010 € /kbit 0.0008 € /kbit
0.29 €/flight
0.63 €/flight
0.0003 € /kbit
0.0010 € /kbit 0.0007 € /kbit
0.29 €/flight
0.61 €/flight
Cost Hypothesis : Space capacity lease from 1 to 2M€/year/MHz/39dBW
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High Hyp.
Scenario
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COST FIGURES (II)
SDLS Service Unit Costs: Results for voice
Distributed SDLS
Architecture
System
Costs
Centralised SDLS
Architecture with new GESs
Centralised SDLS
Architecture with Exi. GESs
Low Hyp.
High Hyp.
Low Hyp.
High Hyp.
Low Hyp.
High Hyp.
7,537.5 k€
18,150 K€
6,512.5 k€
14,050 K€
6,410 k€
13,640 K€
Unit Costs
per min
0.2810 €
0.6766 €
0.2428 €
0.5238 €
0.2390 €
0.5085 €
Unit Costs
per flight
0.50 €
1.21 €
0.44 €
0.94 €
0.43 €
0.91 €
Additional
Party Line
Costs per
flight
0.62 €
0.85 €
0.59 €
0.76 €
0.59 €
Cost Hypothesis : Space capacity lease from 1 to 2M€/year/MHz/39dBW
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PART III - PROJECT STATUS
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EXPERIMENTATION STATUS
 Slide 1 : Initial Feasibility study
 Slice 2 : SDLS Demonstrator Baseline system qualified in July 2002, with :

SDLS Network elements : NMS - GES - 2 AES

SDLS Test Bed : set ATS and AOC applications
SDLS Demonstrator Extension under completion :

System Qualified on ESA Artemis Satellite (September 2003)

Second Access Station deployed in Rome (November 2003)
 Slice 3 : SDLS Operational system study On-going
 SDLS Experimentation Plan for next phase include :

Performance test bench development (transmission and network simulations)

Real life test based on SDLS Demonstrator (with embarked tests)
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Service
Analysis
SDLS SLICE 3 - WBS
SDLS preliminary definition
Demonstrator
trials
SDLS Bearer
Services Analysis
Preliminary System
Design Analysis
ICAO
Support
Economical
aspects
Management
& QA
WP 1
WP 2
WP 3
WP 4
WP 5
WP 6
Demonstrator
experimentation
WP 11
Additional
trials
System
Analysis
System
Concepts
Consolidation
WP302
WP 12
WP301
Feasibility
Study
Montreal
Site Survey
WP 121
WP 122
Economic
Analysis
Services/System
Concepts
consolidation
WP 30
Demonstration
Set-up &
Execution
WP 123
Space Segment
& Frequency issues
WP 31
Fast
Access
Experimentation
WP 32
Detailed
Studies
Waveform
Analysis
WP 33
Protocol
analysis
WP 34
Grey box indicates Phase 1 Work Package*
* WP37,4 and 6 apply to both Phases (1&2)
Interoperability
study
WP 35
System Functional
Specification
Definition
WP 37
Specification
draft issue
Specification
final issue
WP371
WP372
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Consolidation
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SDLS SLICE 3 : STUDY PHILOSOPHY
Making top-down and bottom-up approaches converge
User needs Analysis,
Service
Requirements
Future SATCOM Solution
SDLS
feasibility analysis
and technical solutions
Access ProtocolsWaveform
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Solutions
&
Trade-Offs
SDLS SLICE 3 STUDY OVERVIEW
Detailed Studies
Thales ATM (F)
Indra (SP)
ss
e
c
Ac 32)
P
(W
Integrated Team
AlcatelSpace
QoS
Core System
Mission
Services
Architecture
Waveform
(WP33)
Capacity
Schlumberger
Sema (SP)
Perfos
Pro
to
(WP cols
34)
Diversity
(WP30)
In
te
ro
(W pe
P3 rab
5) ilit
y
Alcatel Bell (B)
Vitrociset (I)
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Airtel (Ir)
Skysoft (P)
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Slice 3 : Operational System Study Status
 Core studies have been conducted
Services and QoS figures defined
Baseline system architecture defined
 Studies currently on-going with short term results expected
Transmission :
 Alternative spreading/scrambling schemes performance evaluation
 Envelope variation minimisation through complex scrambling
 Code reuse between spot using scrambling
 TCM-8PSK evaluation (bandwidth reduction)
 Reduced spreading option analysis in 500kHz bandwidth
Network Architecture :
 Access performance refinement
 Gateway stack definition and performance refinement
 System consolidation activity on-going
Outputs :
 System Design Concepts Justification File
 System Functional Specification
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OPEN ISSUES & WAY FORWARD
 Consolidation of Mission Requirements with Eurocontrol
 Performances Verification
Simulation models to be developed to confirm preliminary results
 network/protocol efficiency, capacity, QoS compliance
 system availability refinement (scintillation effects…)
 Safety assessment
Safety analysis to be performed
 Security requirements
Functions linked to security management could be included in the design if
required (authentication / crypto / ..)
 Experimentation
Leverage existing system demonstrator to validate system key features
(access diversity, gateway prototyping, environmental tests including in-flight
demonstrations)
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EXPERIMENTATION
SDLS 2004 - 2005
SDLS Demonstrator
Flight Test
Pre-Operation
DEVELOPPEMENT
STANDARDISATION
System Prototype
Experimentation
Pre-Operational
System
SDLS Slice 3
SDLS Phase B Completion
System
Specification
SDLS Phase C
MRD V1

PDR
MRD V2
NexSat Initiative
Users
Steering Group
2003
SARPS/MOPS
Contribution to ICAO
2005
2004
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D

CDR