The Digital Video Broadcast (DVB) Project

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The Digital Video Broadcast (DVB) Project

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Agenda

Introduction to The DVB Forum Standards and Specifications portfolio Comparison with competing standards Evolution System Architecture Protocol stack How is HSC involved?

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The DVB Forum

The European Launching Group (PPP) The DVB Forum incorporated in 9/93

Managed by the DVB Project Office of the European Broadcasting Union (EBU), Geneva

Members develop and mutually agree on specifications

Specifications approved by EBU

WG on DTV ~ 300 members (2007)

Open to all organizations

involved in broadcasting technologies

/CENELEC/ETSI/ITU-T/ITU-R; become standards

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The DVB Forum

Timeline of DVB ’91 – ELG (PPP) 9/93 – DVB incorporated with 80 members 11/93 – MPEG2 (ISO/IEC 13818-2) approved by ISO 5/94 – DVB-CSA approved 9/94 – DVB-CA approved 11/94 – ITU comes aboard

3/95 – DVB-CI approved 12/95 – DVB-T approved

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The DVB Forum

Timeline of DVB 4/96 – DVB-T begins trials in the UK ‘96 – DVB-S approved ‘96 – DVB-C approved 4/97 – HDTV compatibility 4/97 – DVB-SIM (Simulcrypt) approved 4/97 – DVB-IPDC approved 4/13/99 – Negotiations with China

7/19/99 – India adopts DVB-T CMMB?

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The DVB Forum

Timeline of DVB 9/99 – Mobile TV demonstrated in trams in

Amsterdam, The Netherlands 4/10/00 – Hierarchical Modulation for simulcast of

HDTV and SDTV on DVB-T

5/00 – DVB-MHP approved 2/14/01 – DVB-RCS approved 4/7/03 – Work on DVB-GEM begins 11/04 – DVB-H approved 2/14/07 – DVB-SH approved

NAB

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Specification and Standardization

The hierarchy General Assembly

Steering Board

DVB Project Office (Project Management)

Commercial Module

Technical Module

IPR Module Public Relations/Communications/Promotions Module

WG

WG

DVB Project Office

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Technical Examine technological implications, explore

available technologies WG reaches consensus Support from CM

Steering Board Overall policy direction, sets priority, co-ordination,

budget, regulatory guidelines

Specification and Standardization The hierarchy Approved!!

(EBU/ETSI/CENELEC/ITU-T/ITU-R) General Assembly

Commercial Market research WG draws up user requirements, market

parameters (pricing, functionality)

IPR IPR issues

Communications and Promotions Branding and Communications

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Salient Features of the DVB standards Market led

Priority to commercial requirements Economies of scale Public benefits!!

Interoperable Independent of OEM Maximum commonality with MPEG2 Transport (ISO/IEC

13818-2) Flexible

Supports PAL, NTSC, SECAM SDTV/HDTV MPEG4-10/H.264, MPEG4-2/H.263+

Innovation Universal adoption

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The DVB standards - Evolution DVB-S (1993)

LoS > 10 GHz Simple QPSK modulation

DVB-C (1994) < 10 GHz DVB-CS for broadcasting a complete satellite channel

mux on a cable channel DVB-T

More complex (NLoS, multipath, fading) First COFDM standard (2K and 8K mode; optional 4K mode) QPSK, 16QAM, 64QAM; optional indepth interleaver for

time diversity Hierarchical modulation 5 (optional)/6/7/8 MHz channels

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The DVB standards - Evolution

DVB-S2 2 versions – one is backward compatible with DVB-S,

the other is not!! EU plans to support both 30% more capacity 8PSK, Turbo coding

DVB-H (2004) NLoS 4K mode, 5 MHz BW mode and indepth interleaver

become compulsory features First standard with Time Slicing for power saving DVB-T + 4K COFDM + Time Slicing + MPE-FEC +

Indepth Interleaver + 5 MHz channel

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The DVB standards - Evolution

DVB-SH (2007) Introduced as DVB-SSP Based on DVB-S and DVB-H principles DVB-H – (CC, RS16) + Turbo coding + 1K COFDM +

1.7 MHz channel bandwidth + Flexible temporal interleaving (Extended MPE-FEC)

Direct satellite link (SC) Complementary ground coverage (CGC) – Gap Filler DVB-SH-A (COFDM on SC and CGC) DVB-SH-B (COFDM on CGC, TDM on SC)

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The competition!!

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Worldwide Coverage – Terrestrial

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Worldwide Coverage – Cable

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Worldwide Coverage - Satellite

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Worldwide Coverage – DVB-H

DVB-SH??

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The Competition….

T-DMB: RS (MPEG) + CC(Viterbi) + Service time interleaver + 2K/1K/½K/¼K mode + DQPSK + 1.5 MHz channel bandwidth

ISDB-T: RS (MPEG) + CC(Viterbi) + sub-band time interleaver + outer (bit) interleaver + inner (symbol) interleaver + DQPSK/QPSK/16QAM/64QAM + 6/7/8 MHz

DMB-TH: BCH + LDPC + Time Interleaver + 4K mode + 4QAM/16QAM/32QAM/64QAM + 6/7/8 MHz

MediaFLO: RS + Turbo Coding + Time Interleaver + 4K mode + TDM/FDM pilots + QPSK/16QAM + 5/6/7/8 MHz

What they do….and how they do it?

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…is beaten handsdown!!!

DVB-H: MPE-FEC (RS64 + Virtual time interleaver) + Time slicing + RS16 + CC(Viterbi) + Outer Interleaver + Inner Interleaver + Indepth Interleaver(optional) + QPSK/16QAM/64QAM + 2K/4K/8K mode + 5/6/7/8 MHz DVB-SH: MPE-FEC (RS64 + Virtual time interleaver) + MPE-FEC Extension + Turbo coding + Outer Interleaver + Inner Interleaver + Indepth Interleaver(optional) + QPSK/16QAM/64QAM + 1K/2K/4K/8K mode + 1.7/5/6/7/8 MHz

What they do….and how they do it?

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System Architecture

SC

CGC

Satellite ComponentComplementary Ground Coverage

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System Architecture – Protocol Stack

PHY

LLC/MAC

Transport/Network

Service

Applications

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LLC/MAC – DVB-H

Reed-Solomon (255,191,64) Forward Error Correction (FEC)

Multi Protocol Encapsulation (MPE)

IP Data

IPv4/v6,< 4096 bytes

188 bytes (ISO/IEC 13818-2 compliant)

PHY

Virtual Time Interleaving1 MPE Frame = 1 to 2 Mbits

MPEG2 Transport Stream (TS) slicer

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LLC/MAC- DVB-SHReed-Solomon (255,191,64) Forward Error Correction (FEC)

Multi Protocol Encapsulation (MPE)

IP Data

IPv4/v6,< 4096 bytes

188 bytes (ISO/IEC 13818-2 compliant)

PHY

Virtual Time Interleaving1 MPE Frame = 1 to 2 Mbits

MPEG2 Transport Stream (TS) slicer

Extended MPE

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PHY – DVB-H

Convolutional Coding (Viterbi)

Reed-Solomon (204, 188, 16) FEC

Bit Interleaver

Symbol Interleaver

Symbol Mapper

MPEG2 TS

188 bytes

Scrambler

Still 188 byte packets!!

Energy dispersal; helps in bit sync

204 x n bytes

Coding rate of n

(Digital modulation - QPSK/16QAM/64QAM; 2/4/6 bits per COFDM symbol)

1 symbol

1 symbol

16QAM64QAM

QPSK

RF

204 bytes

HPLP

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PHY – DVB-SH (simplified)

Turbo coder (Convolutional Coder + inbuilt interleaving)

Symbol Mapper

MPEG2 TS

188 bytes

Scrambler

Still 188 byte packets!!

Energy dispersal; helps in bit sync

(Digital modulation - QPSK/16QAM/64QAM; 2/4/6 bits per COFDM symbol)

1 symbol

1 symbol

16QAM64QAM

QPSK

RF

HP LP

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RF Receiver

Symbol FFT

Antenna

IFFT in transmitter

1K, 2K, 4K, 8K sample FFT per OFDM symbol

Complex number

form (analog)

GSM cutoff

D/A

Decision Feedback (Channel State Information (CSI)) from baseband/MAC

Frequency Domain Equalizer (DFE)

FIR filter (simple sample multiplication due to circular convolution/cyclic prefixing) For GSM850 in

UHF Band V

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Power saving in DVB-H and DVB-SH: Time Slicing

1 OFD

M sy

mbo

l (1/

2/4/

8 K

sub-

carri

ers i

n 1.

7/5/

6/7/

8

MHz)

Tg

Tu

Tu is the useful COFDM symbol period, during which detection takes place using FFT Tg is the Guard Interval (GI) to protect against multipath

Pilot carriers

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Single Frequency Network (SFN)

A unique feature of DVB-H/DVB-SH A single frequency allocated for the entire network Huge cost savings in procuring spectrum during auctions Several engineering challenges

SFN networks are more susceptible to multipath and inter-carrier interference

All transmitters of the network transmit…. ….At the same time ….Same date bits ….At the same carrier frequency

Higher GI used to mitigate effects of more severe multipath in SFN networks However, higher GI means lower capacity and smaller

cell size!!!

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Six Degrees of Freedom GI (Tg)

A fraction of the OFDM symbol time period A higher number translates to better multipath tolerance, but also

means lower capacity and smaller SFN size; less cost effective FFT size (mode)

1 (DVB-SH only)/2/4 (optional in DVB-T/available in DVB-H)/8K mode A higher mode translates to higher capacity but lower tolerance to

Doppler (forces high speed vehicles to a higher bandwidth for same capacity)

Channel bandwidth 1.7 MHz (DVB-SH only), 5 MHz (optional in DVB-T/available in DVB-H), 6

MHz, 7 MHz, 8 MHz Modulation scheme

QPSK (4QAM), 16QAM, 64QAM 4QAM - lowest capacity (2 bits/sub-carrier); least susceptible to noise 64QAM - highest capacity (6 bits/sub-carrier); most susceptible to noise

Carrier frequency Lower frequency for faster vehicles, but larger antenna size VHF to S Band (DVB-H), C/Ku/Ka bands (DVB-SH)

Hierarchical Modulation HDTV/SDTV, MPEG2/IP multiplexing

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Doppler performance

Shinkansen/Shanghai MaglevTGV

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Members

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Members

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How is HSC involved?

+ = ?? Opportunities are being explored

Possible leverage in DVB-MHP, DVB-GEM, IPTV Tracking of DVB-SH, DVB-H2, DVB-T2 and DVB-S2

(DVB 2.0) specifications Integration of DVB-H and DVB-SH onto GMR-1 HNS + HSC + Terrastar

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Thank You