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Giovanni GarofaloEuropean Space
Agency
DVB RCS Standards&
Future Evolutions
DVB-RCS defines a return channel over satellite for broadband systems based on DVB-S(2) forward linkSpecification initially defined by satellite operators working under the auspices of ESAWork taken over by DVB Project, which is responsible for standard maintenanceETSI approves its publication as EN 301 790, according to their defined proceduresDefinition started in Sept 1997Editions
•1st (v1.2.2)12/00•2nd (v1.3.1) 03/03: RSAT•3rd (v1.4.1) 09/05: DVB-S2
DVB-RCS Background
Openness All stakeholders participate in the standards development process
Consensus All interests are discussed and agreement found
Due Process Balloting and appeal process may be used to find resolution
Open IPR Holders of Intellectual Property Rights (IPR) must identify themselves during the standards development process
Open World Same standard for the same function world-wide
Open Access Open access committee: documents, drafts and completed standards
Open Meeting All may participate in standard development meetings
On-going Support Standards supported until user interest ceases rather than when provider interest declines
Open Interfaces Allow additional functions, public or proprietary
Open Use Low or no charge for IPR necessary to implement an accredited standard
Open Standards Principles
The case of DVB-RCS:The case of DVB-RCS: Open standard
Scrutinised, optimised, built by consensusBased on commercial requirementsBroad range of services and applications
supportedFuture-proof (e.g. DVB-S2) Based on successful DVB-SAvailability of mass market low cost satellite
TV receivers
Enables interoperability between products
The case of DVB-RCS:The case of DVB-RCS: Multiple implementations
Several system integrators
Several terminal-only suppliers
Different choices of options and parameters
Several generations of system implementations Cost & feature optimised
Enables interoperability between products
SatLabs Group basics• Association set up to bring the DVB-RCS standard to large-
scale adoption– Foster availability of interoperable products– Ensure availability of solutions for interoperability testing and
certification
• Membership open to all organizations worldwide interested in the DVB-RCS standard
• Main emphasis on interoperability but addressing other aspects related to DVB-RCS implementation
• Creation: October 2001
SatLabs Membership
Service + Access Provider
Satellite Operator
Satellite Supplier
System Supplier
Equipment Supplier
Techno Supplier
Avanti
Aramiska
FranceTelecom
MonacoTelecom
Satlynx
Eutelsat
HellasSat
Hispasat
JSAT
NewSkies
SESAstra
Telesat
Alcatel
Astrium
Alcatel
EMS
Gilat
HNS
Nera
Newtec
Pentamedia
Shiron
ViaSat
Alcatel Bell
NDSatcom
Thomson
AASKI
Invacom
Skyware
Spacebridge
STMicro
Verisat
Visiosat
DVB-RCS StandardsDVB-RCS StandardsOverviewOverview
Network Control Centre: a NCC provides
Control and Monitoring Functions (CMF). It generates control and timing signals for the operation of the Satellite Interactive Network to be transmitted by one or several Feeder Stations.Traffic Gateway: a TG receives the RCST return signals, provides accounting functions, interactive services and/or connections to external public, proprietary and private service providers (data bases, pay-per-view TV or video sources, software download, tele-shopping, tele-banking, financial services, stock market access, interactive games etc.) and networks (Internet, ISDN, PSTN, etc.). Feeder: a Feeder transmits the forward link signal, which is a standard satellite digital video broadcast (DVB-S or DVB-S2) uplink, onto which are multiplexed the user data and/or the control and timing signals needed for the operation of the Satellite Interactive Network.
RCST
NCC
SAT FW SAT RT
RCST
NETWORK 1 NETWORK 2InteractiveNetworkAdapter
FEEDER 1STATION
GATEWAY 1STATION
DVB ForwardLink 1
DVB ForwardLink 2
RCSTReturn Link
RCST RCST
GATEWAY 2STATION
FEEDER 2STATION
BroadcastNetworkAdapter
InteractiveServiceProvider
BroadcastServiceProvider
DVB-RCS Reference Diagram
MAC Characteristics
Continuous Rate Assignment
Rate Based Dynamic Capacity
Volume Based Dynamic Capacity
Burst characteristics
Overhead Bursts
SAC
encoded burst Preamble
Randomized SAC
SAC_lengthbytes
encoded burst Preamble
Rand . RCST capa
Rand . RCST MAC
address
RCST capa RCST
MAC address
Rand . reserved
reserved Burst type
identifier
. Burst type
identifier Rand . CSC
Route ID
CSC Route ID
Rand . Dynamic
Connectivity
Dynamic Connectivity
Rand . Frequency Hopping
Frequency Hopping
Rand
Frequency sequencePreamble
MF-TDMA (Multi Frequency TDMA)
frame
terminal 1 terminal 2
terminal 3
Terminal architecture
Interfacility Link: RX cable: FL signal on L-Band (950 – 2150 MHz)+ polarization control +DC power (~10-20 volts) + to LNB (Low Noise Block) + 22 KHz tone (LNB frequency band adjustment)
• TX cable: RT link L-Band TX (950-1450 MHz)+10 MHz reference signal to ODU (BUC) + DC power to the BUC (20-30 volts) + 22 KHz PWK (Pulse Width Keying)
DiSEqC toneDiSEqC (Digital Satellite Equipment Control): SSPA ON/OFF, TX frequency band
selection, …, ODU monitoring (SSPA status, PLL status, …)
IDU TRANSCEIVER
USERPC
INTERFACILITYLINK
ODU
Hub Architecture (1)
FLSS (Forward Link Subsystem)•IP/DVB encapsulator
•Injects IP packets into MPEG2/DVB compliant Transport Stream
•MPEG2-DVB Multiplexer: •Combines the MPEG Transport Streams from the IP/Encapsulator and the RLSS Controller/Scheduler
PCR InserterGenerates a 27 MHz reference clock and inserts relative time stamps in the FW link for network synchronization.
DVB ModulatorModulates the signal to IF frequency (L-
band) according to the DVB-S or DVB-S2 standard
Hub Architecture (2)
RLSS (Return Link Subsystem)•MCD (Multiple Carrier Demodulator):
•Demodulation of return path carriers, De-Multiplexing of traffic and Signaling•Timing/frequency corrections
•Receiver Traffic: •ATM recovery from Satellite cells. •Interface with ISP through ATM Switch
•Receiver Signaling: •Forward received signaling to Controller/scheduler.
•Control/Scheduler Controls SITs entry and generates all Satellite signaling on the forward path•OAM (Operation, Administration and Maintenance)
•Responsible for initializing, configuring and monitoring all RLSS functions to ensure proper operation
Hub Architecture (3): IPSS
DVB-S versus DVB-S2DVB-S
Multiple streams: No Input bit rate: fixed Coding: Reed Solomon plus
convolutional encoding Coding rates: ½, 2/3, ¾, 7/8 Input I/F: MPEG TS Symbols mapping: Gray Modulation format: QPSK Pilot symbols: None Symbols shaping: Square-
Root Raised Cosine filter =0.35 Transmission mode: constant Coding and Modulation
DVB-S2 Multiple streams: Yes Input bit rate: variable frame-by-frame Coding: BCH + Low-Density Parity
Check Codes (LDPC) Coding rates: ¼, 1/3, 2/5, ½, 3/5, 2/3, ¾,
4/5, 5/6, 8/9, 9/10 Symbols mapping: BICM (Gray) Modulation format: QPSK, 8PSK,
16APSK, 32APSK Pilot symbols: Optional Symbols shaping: Square-Root Raised
Cosine filter =0.2, 0.25, 0.35 Input I/F: MPEG-TS, IP Transmission modes: Constant Coding
and Modulation, Variable Coding and Modulation, Adaptive Coding and Modulation
DVB-S2/DVB-S Summary bit-rate gain (same C/N and symbol-rate):
25-35% depending on modes and applications Large flexibility to potentially match any transponder
characteristics: Spectrum efficiencies from 0.5 to 4.5 bit/s/Hz C/N range from –2.4 to +16 dB with 1 dB granularity
(AWGN)
0.7 – 1 dB from the Shannon limit probably means that: “In the course of our lifetime we will never have
to design another system for satellite broadcasting”
Alternative
VSAT
Access Systems
IPoS: IP over satellite• Originally published as TIA-1008,
now also co-published by ETSI• Promoted by HNS• Always-on IP service: once
registered the terminal does not need to ever log-on again
• Protocol architecture separate satellite-dependent functions and satellite independent functions via the SI-SAP interface positioned between the MAC and Network Layer. Elements above the SI-SAP can be designed without knowledge of the supporting satellite link layer
• Return link access similar to DVB-RCS but with O-QPSK and variable length bursts
• Support of contention-based access
DOCSIS-S• Originally developed as terrestrial cable modem standard• Promoted by ViaSat• Consists of terminals (CM; Cable Modems) and Hub’s
(CMTS: Cable Modem Termination System)• DOCSIS-S implements DOCSIS 1.1 above the PHY Layer
and a satellite specific PHY Layer• Potential to save some costs on reuse of higher layer
components• Benefits from the availability of a very mature sets of
infrastructure products for network control, system management, subscriber management and billing systems
• FW link PHY based on turbo code with ACM (QPSK and 8PSK)
• MAC layer contains a 6 byte MAC header and a ETHERNET packet as a payload. Encapsulation of IP packets requires an additional 17 Bytes header and a CRC32
VIASAT SurfBeam System
• Telesat is using SurfBeam for consumer services in Canada on new Anik F2 Ka-band, spot beam satellite
SurfBeam: ACM
Satcom Systems: comparison
DOCSIS vs. DVB-RCS
Future DVB-RCS Standards Improvement Axis
Future Systems
83.33MHz Polarisation
H
V
166.67MHz
41.67MHz
Return Uplink:
[29.916 ; 30] GHz
Return Downlink:
[18.033 ; 18.2] GHz
V H or V depending
on the beam where
the gateway is
located
Based on WEB (West Early Bird) system design
Improved Coding Scheme
QPSK
Performance is improved by as much as 1.2 dB!
1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,01E-10
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
0,1
1
10
1E-10
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
0,1
1
106-bit quantization --- 8 iterations
R=0.5k=1728
R=0.56597k=1304
R=0.52222k=3008 R=0.65278
k=3008
R=0.65278k=1504
8PSK Modulation
EB/N0
k=1304 R=0.56597 BER FER k=1728 R=0.5 BER FERk=1504 R=0.65278 BER FER k=3008 R=0.65278 BER FER k=3008 R=0.52222 BER FERtheoritical limit FER
8PSK
Optimum bits-> symbol mapping strategy Several rates available
Preliminary Results
Efficient FMT’s require the implementation of high order modulations (8PSK and 16APSK)Adaptive Coding and Modulation already successfully implemented in the DVB-S2 FW link
Fading Mitigation Techniques
Received power
Transmitted power
Nominal power target
FMT: UPC (Upstream Power Control)
FMT: DRA (Dynamic Rate Adaptation)
FMT: ACM (Adaptive Coding and Modulation
UPC case
ACM in the RT link 60% capacity increase!
Improvement Axis (2) Efficient Framing/Encapsulation: utilization of few
burst lengths, which are multiples of a basic slot size
0.7 0.8 0.9 1 1.1 1.2 1.3 1.43.5
4
4.5
5
5.5
6
6.5
7
No. of IP-bits per channel symbol
Ene
rgy
per
IP-b
it/N
o (d
B)
Block length=188-bytes, PER=1e-6, AIPLEN=100 bytes, ATRAINLEN=500 bytes
DVB-RCS MPE/MPEG
Optimised Encapsulation and Segmentation
20% Efficiency gain
Continuous Phase Modulations for Return Channel:Reduced complexity for receiver!
Random Access together with DAMA:
Adapts very well to bursty type of traffic and to consumer user profile
ESA Strategy for
DVB-RCS
ESA and DVB-RCS: BackgroundESA has played a key role in the definition of the DVB-RCS standard since its initial stages.ESA actively supports the development of DVB-RCS in the following areas:
DVB-RCS standardization Technology R&D System R&D Application development Pilot projects
SatLabs GroupESA fostered the creation of the SatLabs Group and is leading its tasks
• Ensure interoperability between DVB-RCS terminals and systems
• Achieve low-cost implementations of DVB-RCS products• ESA is chairing the SatLabs Group• ESA leads most working groups and actively participates
in the technical tasks directly or through funded studies• Key developments for the implementation of
interoperability verification are carried out by ESA– Common Test Bed for interoperability testing
• ESA funds through ARTES lines key technological developments needed to reduce DVB-RCS cost– Low cost Components– Low cost installation mechanisms
Applications
Applications are the bridge between the End User and the DVB-RCS technology
ESA has developed and integrated DVB-RCS HW/SW elements and contents under ARTES program in order to generate new applications with commercial potential, and addressing the capability to provide the applications in an Operational Context
• Supporting provision of Broadband Access Services through PILOT projects: All activities involve a user community through a pre-operational phase of actual utilisation of the system (e.g. Broadband in the Sky, Pacific Skies, Inspire, SpaceforScience)
• Developing “Applications” suitable for DVB-RCS broadband access services Telemedicine Teleducation Secure access E-government Infomobility B2B
Budget evolution DVB-RCS R&D
0
10
20
30
40
50
60
2001 2002 2003 2004 2005
ESA R&D Funding (MEur)
ARTES 5
ARTES 4
ARTES 3
ARTES 1