1. DVB RCS Standards & Future Evolutions
Giovanni Garofalo
European Space Agency

2. DVB-RCS Background
DVB-RCS defines a return channel over satellite for broadband systems based on DVB-S(2) forward link
Specification initially defined by satellite operators working under the auspices of ESA
Work taken over by DVB Project, which is responsible for standard maintenance
ETSI approves its publication as EN , according to their defined procedures
Definition started in Sept 1997
Editions
1st (v1.2.2)12/00
2nd (v1.3.1) 03/03: RSAT
3rd (v1.4.1) 09/05: DVB-S2

3. Open Standards Principles
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

4. Enables interoperability between products
The case of DVB-RCS:
Open standard
Scrutinised, optimised, built by consensus
Based on commercial requirements
Broad range of services and applications supported
Future-proof (e.g. DVB-S2)
Based on successful DVB-S
Availability of mass market low cost satellite TV receivers
Enables interoperability between products

5. Enables interoperability between products
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

6. 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

7. SatLabs Membership Service Satellite Satellite System Equipment Techno
+ 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
EMS
Gilat
HNS
Nera
Newtec
Pentamedia
Shiron
ViaSat
Alcatel Bell
NDSatcom
Thomson
AASKI
Invacom
Skyware
Spacebridge
STMicro
Verisat
Visiosat

8. DVB-RCS Standards
Overview

9. DVB-RCS Reference Diagram
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.

10. MAC Characteristics Continuous Rate Assignment
Volume Based Dynamic Capacity
Rate Based Dynamic Capacity

11. Burst characteristics

12. Overhead Bursts

13. MF-TDMA (Multi Frequency TDMA)
terminal 1
terminal 2
frame
terminal 3

14. 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 ( MHz)+10 MHz reference signal to ODU (BUC) + DC power to the BUC (20-30 volts) + 22 KHz PWK (Pulse Width Keying)
DiSEqC tone
DiSEqC (Digital Satellite Equipment Control): SSPA ON/OFF, TX frequency band selection, …, ODU monitoring (SSPA status, PLL status, …)

15. FLSS (Forward Link Subsystem)
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 Inserter
Generates a 27 MHz reference clock and inserts relative time stamps in the FW link for network synchronization.
DVB Modulator
Modulates the signal to IF frequency (L-band) according to the DVB-S or DVB-S2 standard

16. RLSS (Return Link Subsystem)
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

17. Hub Architecture (3): IPSS

18. DVB-S versus DVB-S2 DVB-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

19. 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”

20. Alternative VSAT Access Systems

21. 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

22. 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

23. VIASAT SurfBeam System
Telesat is using SurfBeam for consumer services in Canada on new Anik F2 Ka-band, spot beam satellite

24. SurfBeam: ACM

25. Satcom Systems: comparison

26. DOCSIS vs. DVB-RCS

27. Future DVB-RCS Standards Improvement Axis

28. Based on WEB (West Early Bird) system design
Future Systems
Based on WEB (West Early Bird) system design

29. Improved Coding Scheme
QPSK
8PSK
Performance is improved by
as much as 1.2 dB!
Optimum bits-> symbol mapping strategy
Several rates available
Preliminary Results

30. Fading Mitigation Techniques
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
FMT: ACM (Adaptive Coding and Modulation
Received power
Transmitted power
Nominal power target
ACM in the RT link
60% capacity increase!
FMT: DRA (Dynamic Rate Adaptation)
FMT: UPC (Upstream Power Control)
UPC case

31. Improvement Axis (2) 20% Efficiency gain
Efficient Framing/Encapsulation: utilization of few burst lengths, which are multiples of a basic slot size
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

32. ESA Strategy for DVB-RCS

33. ESA and DVB-RCS: Background
ESA 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

34. SatLabs Group
ESA 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

35. 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

36. Budget evolution DVB-RCS R&D