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

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