1

University of Canberra Advanced Communications Topics

University of Canberra Advanced Communications Topics

Television Broadcasting Television Broadcasting into the Digital Erainto the Digital Era

by: Neil Pickfordby: Neil PickfordLecture 4Lecture 4

Error Correction, Error Correction, DTTB Planning &DTTB Planning &

System InformationSystem Information

2

64-QAM - Perfect & Failure64-QAM - Perfect & Failure

3

COFDM DTTB Block DiagramCOFDM DTTB Block Diagram

Error CorrectionError Correction

4

Forward Error Correction (FEC) Forward Error Correction (FEC) Broadcast transmissionBroadcast transmission

One way process - Tx to RxOne way process - Tx to Rx Not possible to repeat any errored dataNot possible to repeat any errored data

Forward Error Correction is a technique used to Forward Error Correction is a technique used to improve the accuracy of data transmissionimprove the accuracy of data transmission

Extra redundant bits are added to the data streamExtra redundant bits are added to the data stream Error correction algorithms in the demodulator Error correction algorithms in the demodulator

use the extra FEC bits to correct data errorsuse the extra FEC bits to correct data errors C C OFDM uses a OFDM uses a ConvolutionalConvolutional FEC code FEC code

EncodeEncodeN bitsN bits N bitsN bitsTx/RxTx/Rx

N+CodeN+Code

DecodeDecode

N+Code+ErrorN+Code+Error

5

Convolutional CoderConvolutional Coder

1-Bit1-BitDelayDelay

1-Bit1-BitDelayDelay

1-Bit1-BitDelayDelay

1-Bit1-BitDelayDelay

1-Bit1-BitDelayDelay

1-Bit1-BitDelayDelay

DataDataInputInput

Y OutputY Output

10110111011011

X OutputX Output11110011111001

6 5 4 3 2 1 06 5 4 3 2 1 0

6

Puncturing Codes (FEC) Puncturing Codes (FEC) The X and Y outputs of the Convolutional coder The X and Y outputs of the Convolutional coder

are selected in a Puncturing patternare selected in a Puncturing pattern

7

Inner CodingInner Coding Convolutional coder generates the X & Y codesConvolutional coder generates the X & Y codes

ConvolutionalConvolutionalEncoderEncoder

PuncturingPuncturing InterleaverInterleaverDataDataCodedCodedDataData

XX

YY

Puncturing operation selects X & Y in sequencePuncturing operation selects X & Y in sequence Result then scrambled with an interleaverResult then scrambled with an interleaver

8

Viterbi DecoderViterbi Decoder A special type of data decoder designed to work A special type of data decoder designed to work

with convolutional FEC codeswith convolutional FEC codes Uses the past history of the data to identify valid Uses the past history of the data to identify valid

future data valuesfuture data values Element in the Receiver OnlyElement in the Receiver Only

9

Reed Solomon (RS)Reed Solomon (RS) RS is a Block data correcting CodeRS is a Block data correcting Code Hamming type cyclic Polynomial sequenceHamming type cyclic Polynomial sequence

Code Generator Polynomial:Code Generator Polynomial: g(x) = (x+ g(x) = (x+00)(x+)(x+11)(x+)(x+22)...(x+)...(x+1515), ), =02 =02 HexHex

Field Generator Polynomial:Field Generator Polynomial: p(x) = x p(x) = x88 + x + x44 + x + x33 + x + x22 + 1 + 1

Has special ability to correct multiple bursts of Has special ability to correct multiple bursts of errors in a code blockerrors in a code block

DVB-T uses 204 bytes for each 188 byte PacketDVB-T uses 204 bytes for each 188 byte Packet(ATSC uses 207 bytes for each 187 byte Packet)(ATSC uses 207 bytes for each 187 byte Packet)

Can correct 8 bytes in each 204 byte packetCan correct 8 bytes in each 204 byte packet

10

Error Protection - OrderError Protection - Order

Outer CodeOuter CodeRSRS

(204,188)(204,188)

DataDataInputInput

InterleaverInterleaver InterleaverInterleaver

Inner CodeInner CodeFECFEC(2/3)(2/3)

ErrorErrorProtectedProtected

DataDataMapperMapper

188188BytesBytes

204204BytesBytes

204204BytesBytes

306306BytesBytes

6 bits x 1512 Carriers6 bits x 1512 Carriers6 bits x 6048 Carriers6 bits x 6048 Carriers

24482448BitsBits

64 QAM64 QAM

11

DVB-T - Bit Rates [2k]

CodeRate

QPSK 16 -

QAM

64 -

QAMQPSK QPSK16 -

QAM

64 -

QAM

64 -

QAM

16 -

QAM

D/Tu = 1/4 D/Tu = 1/8 D/Tu = 1/32

1/2

2/3

3/4

5/6

7/8

4.35

5.81

6.53

7.26

7.62

8.71

11.61

13.06

14.51

15.24 22.86

21.77

19.59

17.42

13.06 4.84

6.45

7.26

8.06

8.47 16.93

16.13

14.51

12.90

9.68 14.51

19.35

21.77

24.19

25.40

5.28

7.04

7.92

8.80

9.24 18.47

17.59

15.83

14.07

10.56 15.83

21.11

23.75

26.39

27.71

64 us 32 us 8 us7 MHz

Page 21 Table A1 - AS4599-1999Page 21 Table A1 - AS4599-1999

12

DVB-T - C/N Values

CodeRate QPSK

16 -QAM

64 -QAM QPSK QPSK

16 -QAM

64 -QAM

64 -QAM

16 -QAM

1/2

2/3

3/4

5/6

7/8

3.10

4.90

5.90

6.90

7.70

8.80

11.1

12.5

13.5

13.9 20.10

19.30

18.00

16.5

3.60

5.70

6.80

8.00

8.70 15.00

14.40

13.00

11.60

9.60 14.70

17.10

18.60

20.00

21.00

5.40

8.40

10.70

13.10

16.30 22.80

19.30

16.70

14.20

11.20 16.00

19.30

21.70

25.30

GAUSSIAN RICEAN RAYLEIGH

27.90

14.4

Simulated Theoretical Thresholds (bandwidth independent)

13

C/N - Signal Level PerformanceC/N - Signal Level Performance

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

10 15 20 25 30 35 40 45 50 55 60

64QAM 7/8 FEC64QAM 5/6 FEC64QAM 3/4 FEC64QAM 2/3 FEC64QAM 1/2 FEC16QAM 7/8 FEC16QAM 5/6 FEC16QAM 3/4 FEC16QAM 2/3 FEC16QAM 1/2 FECQPSK 7/8 FECQPSK 5/6 FECQPSK 3/4 FECQPSK 2/3 FECQPSK 1/2 FEC8VSB Test Rig

Receiver Signal Level (dBuV)

C/N

Thr

esho

ld (

dB)

1010 1515 2020 2525 3030 3535 4040 4545 5050 5555 6060

8

0

16

4

12

20

24

28

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General Parameters - Aust TestsGeneral Parameters - Aust Tests

ParameterParameter DVB-TDVB-T ATSCATSC

Data PayloadData Payload 19.35 Mb/s19.35 Mb/s 19.39 Mb/s19.39 Mb/s

CarriersCarriers 17051705 11

Symbol TimeSymbol Time 256 us256 us 93 ns93 ns

Time InterleavingTime Interleaving 1 Symbol1 Symbol 4 ms4 ms

Reed Solomon code rateReed Solomon code rate 188/204188/204 187/207187/207

IF Bandwidth (3 dB)IF Bandwidth (3 dB) 6.67 MHz6.67 MHz 5.38 MHz5.38 MHz19

15

8VSB vs COFDM Latest

35

30

25

19

15

0-3 -15Multipath Level (dB)

TrueCOFDM

Advantage

True ATSC Advantage

RealisticCOFDMperformance

8VSB

Max Analog Ghost

16

7 MHz Theoretical DVB Transmission signal spectrum

-60

-50

-40

-30

-20

-10

0

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

7 MHz COFDM Modulator Spectrum7 MHz COFDM Modulator Spectrum

8k 1/32 Guard8k 1/32 Guard2k 1/32 Guard2k 1/32 Guard

00

-10-10

-20-20

-30-30

-40-40

-50-50

00-1-1-2-2-3-3-4-4-5-5-6-6-7-7-8-8 11 22 33 44 55 66 77 88Frequency Offset (MHz)Frequency Offset (MHz)

Pow

er S

pect

rum

Den

sity

(dB

)P

ower

Spe

ctru

m D

ensi

ty (

dB)

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Frequency Planning Fundamental Matter Fundamental Matter - - Scarce ResourceScarce Resource Analogue Rules set limit to more ServicesAnalogue Rules set limit to more Services No NEW TV Spectrum is AvailableNo NEW TV Spectrum is Available Digital Transmission changes RulesDigital Transmission changes Rules

Signals have different behaviourSignals have different behaviour Digital Signals can occupy unused spaceDigital Signals can occupy unused space - -

“Taboos”“Taboos” Digital Needs to fit in with Existing PALDigital Needs to fit in with Existing PAL Eventually Digital Only Eventually Digital Only - - but long wait??but long wait??

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Digital Has to Fit In With PALDigital Has to Fit In With PAL

World TV channel bandwidths varyWorld TV channel bandwidths vary USA / Japan 6 MHzUSA / Japan 6 MHz

Australian 7 MHzAustralian 7 MHz

Europeans 8 MHzEuropeans 8 MHz

Affects:-Affects:- tuning, filtering, interference tuning, filtering, interference & system performance& system performance2828

2828

2828

3030

30302929

2929

3131

3131 3232 3333 3434 3535

3535

35353434

34343333

3333

3232

3232

313130302929

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Channel SpacingChannel Spacing Existing analog TV channels are spaced so they do not Existing analog TV channels are spaced so they do not

interfere with each other.interfere with each other. Gap between PAL TV servicesGap between PAL TV services

VHF 1 channelVHF 1 channel UHF 2 channelsUHF 2 channels

Digital TV can make use of these gapsDigital TV can make use of these gaps

Ch 7 Ch 8 Ch 9Ch 6 Ch 9A

VHF Television Spectrum

Taboo Taboo Taboo

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Digital ChallengesDigital Challenges Digital TV must co-exist Digital TV must co-exist

with existing PAL serviceswith existing PAL services DTV operates at lower powerDTV operates at lower power DTV copes higher interference levelsDTV copes higher interference levels Share transmission infra-structureShare transmission infra-structure DTV needs different planning methods DTV needs different planning methods

Ch 7 Ch 8 Ch 9Ch 6 Ch 9A

VHF Television Spectrum

8-VSB COFDM

21

DTTB & PALDTTB & PAL

UHF Channels: London

Photograph by courtesy and © BBC R&D

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Planning Issues Channel Disturbances:Channel Disturbances:

Noise, at edge of area with NO interferenceNoise, at edge of area with NO interference Interference, Co Channel Interference and Adjacent Interference, Co Channel Interference and Adjacent

Channel InterferenceChannel Interference Multipath, Echoes:How Many, How Large, Moving?Multipath, Echoes:How Many, How Large, Moving?

Antenna Pattern?Antenna Pattern? Static Roof Top? Directional? Wideband?Static Roof Top? Directional? Wideband? CCIR Antenna Rec BT-419-3CCIR Antenna Rec BT-419-3 Portable Receivers? No Antenna?Portable Receivers? No Antenna?

Frequency Re-Use DistancesFrequency Re-Use Distances Terrain DataTerrain Data Propagation Models Propagation Models Protection RatiosProtection Ratios

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Signal Strength

SIGNAL STRENGTH, MicroVolts

TIME

MEAN

RECEIVER C/N LIMIT

REGION OF SERVICEFAILURES FORPERCENTAGE

OF TIME

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Digital Service Area PlanningDigital Service Area Planning Analog TV has a slow gradual failureAnalog TV has a slow gradual failure

Existing PAL service was planned for:Existing PAL service was planned for:50 % availability at 50 % availability at 50 % of locations50 % of locations

Digital TV has a “cliff edge” failureDigital TV has a “cliff edge” failure Digital TV needs planning for:Digital TV needs planning for:

90-99 % availability at 90-99 % availability at 90-99 % of locations90-99 % of locations

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TV System Failure CharacteristicTV System Failure Characteristic

Good

RottenClose Far

Distance

Quality

Edgeof

ServiceArea

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TV System Failure CharacteristicTV System Failure Characteristic

Good

RottenClose Far

Distance

Quality

Edgeof

ServiceArea

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TV System Failure CharacteristicTV System Failure Characteristic

Good

RottenClose Far

Distance

Quality

Edgeof

ServiceArea

SDTV

HDTV

PAL

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Service Area PlanningPICTUREQUALITY

C/N

ANALOGUE

DIGITAL

THRESHOLD OFACCEPTABILITY

5

4

3

2

1

NOSERVICE

10 15 20 25 30 40 45

ANALOGUEFAILURE

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ModulationDependent Variation

TypicalChoice of

C/N

30

Service Areas - Current

50 - 100 KILOMETRES

TRANSMITTER BTRANSMITTER A

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Service Areas - SFN

TRANSMITTER B

50 - 100 KILOMETRES

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Digital Provides New ConceptsDigital Provides New Concepts Single frequency networks (SFNs) can help Single frequency networks (SFNs) can help

solve difficult coverage situationssolve difficult coverage situations SFNs allow the reuse of a transmission frequency SFNs allow the reuse of a transmission frequency

many times in the same area so long asmany times in the same area so long as exactly the same program is carriedexactly the same program is carried

Allows lower power operationAllows lower power operation Better shaping of coverageBetter shaping of coverage Improved service availabilityImproved service availability Better spectrum efficiencyBetter spectrum efficiency

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MPEG PacketMPEG Packet

24 8 16

OPTIONALPES

HEADER

8

2 1 1 1 1 1 12 1 1 1 1 1 8

33 42 22 8

8

PACKET START CODE PREFIX STREAMID

PESPACKETLENGTH

STUFFING

BYTESDATA BYTES

33 16

10

PSCPESP

DAICY

OOC

PESHEADER

DATALENGTH

OPTIONAL

FIELDS

PTS DTS ESCRES

RATE

DSMTRICKMODE

PES

CRC

OPTIONAL

FIELDS

ADDITIONALCOPYINFO

1 1 1 1 1

PESPRIVATE

DATA

PACKHEADER

FIELD

PES

EXTENSION

FIELDP-STD

BUFFER

PROGRAMPACKET

SEQUENCECOUNTER

PES

EXTENSION

PTSDTSFESCRFESRFDSMTMFACIFPESCRCFPESHDL

5 FLAGS

PESSC = Packet Elementary Stream Scrambling ControlPESP = Packet Elementary Stream PriorityDAI = Data Alignment IndicatorCY = CopyrightOOC = Original or CopyPTSDTSF = PTS & DTS FlagsESCRF = ESCR FlagESRFES = Rate FlagDSMTMF = Trick Mode FlagACIF = Additional Copy Info. FlagPESCRCF = PES Extension FlagPESHDL = PES Header Data LengthPTS = Presentation Time StampDTS = Date Time Stamp

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System Level Multiplexing ApproachesSystem Level Multiplexing Approaches

VideoEncoder Packetizer

PSMux

Video PES

Program Stream

VideoData

AudioEncoder Packetizer

TSMux

Audio PESTransport Stream

AudioData

35

Packetisation ApproachesPacketisation Approaches

Audio Video Audio Audio Video Video Video Audio Audio Video Video Audio Video Audio Audio

Transport Stream

Audio Video Audio Video

Program Stream

Fixed LengthFixed Length

Variable LengthVariable Length

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Transport StreamTransport Stream188 Bytes

4 Bytes

Link Header

Adaptation Header (Variable Length)

Payload

not to scale

sync_byte(0x47)

13 bit PID Adaptation headerorpacket payload

1 bit: transport_priority

1 bit: payload_unit_start_indicator

1 bit: transport_packet_error_indicator

4 bit: continuity_counter

2 bit: adaptation_field_control

2 bit: transport_scrambling_control

Link Header FormatLink Header Format

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System Information (SI)System Information (SI)

Required for :Required for :Automatic Tuning of receiver upon selectionAutomatic Tuning of receiver upon selection

Program locationProgram location

EPG (Electronic Program Guide)EPG (Electronic Program Guide)

API (Application Programming Interface)API (Application Programming Interface)

CA (Conditional Access)CA (Conditional Access)

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DVB SI ModelDVB SI Model

Bouquet

Satellite Cable Terrestrial

NetworksNetworks

Transponder1

Transponder1

Transponder2

Transponder2

Transponder3

Transponder3

TransponderT

TransponderT

Channel1

Channel1

Channel2

Channel2

ChannelC

ChannelC

Channel1

Channel1

Channel2

Channel2

ChannelC

ChannelC

Transport StreamsTransport Streams

Service1

Service1

Service2

Service2

Service3

Service3

ServiceS

ServiceS

Service1

Service1

Service2

Service2

ServiceS

ServiceS

Service1

Service1

Service2

Service2

ServiceS

ServiceS

ServicesServices

VideoVideo Audio 1Audio 1 Audio 2Audio 2 DataData

ComponentsComponents

39

System InformationSystem Information The DVB SI structure has it’s derivation in The DVB SI structure has it’s derivation in

MPEG ISO/IEC 13818-1 and is defined in a MPEG ISO/IEC 13818-1 and is defined in a set of tables.set of tables.

The primary link between DVB SI and MPEG The primary link between DVB SI and MPEG is the“PSI” (Program Specific Information) is the“PSI” (Program Specific Information) in MPEG and is contained primarily in the in MPEG and is contained primarily in the “PAT”, “PMT” and “CAT” set of tables“PAT”, “PMT” and “CAT” set of tables

40

What is SI?What is SI? SI data provides information for:SI data provides information for:

Automatic tuning to transport streamAutomatic tuning to transport stream User Information for:User Information for:

Service selectionService selection ““Event” selectionEvent” selection ““Component” selectionComponent” selection

PSI data provides information for:PSI data provides information for: Configuration of decoder for selected ServiceConfiguration of decoder for selected Service DVB extensions for non-MPEG componentsDVB extensions for non-MPEG components

41

PSI and DVB SI TablesPSI and DVB SI TablesPSI and DVB SI TablesPSI and DVB SI Tables

CAT

PAT

PCR

MPEG DVBMANDATORY

TSDT

SDTOTHER

TS

DVB OPTIONAL

NITOTHER

Delivery Sys.

TOT

TIMEOFFSET.

RST ST

STUFFINGTABLE.

BAT

RUNNINGSTATUS.

SERVICEDESCRIPTION.

NETWORKINFORMATION.

EVENTINFORMATION.

BOUQUETINFORMATION.

PID=Ox0001

PID=0x0000

PID=0X0002

PID=P

NITACTUAL

Delivery Sys.

EITACTUAL

TS

SDTACTUAL

TS

TDT

PROGRAMMECLOCK REF.

PID=Ox0011

PID=0x0010

PID=Ox0011

PID=0x0010

PID=0X0012

PID=0X0012

PID=Ox0011

TIME ANDDATE.

PMT

EITOTHER

TS

EITACTUAL

TS

42

MPEG Program PIDsMPEG Program PIDs What is a program ?What is a program ?

MPEG has a definition which is different to that MPEG has a definition which is different to that normally understood.normally understood.

A “program” in broadcasting is a collection of A “program” in broadcasting is a collection of elements with a common time base and the same elements with a common time base and the same start and stop times.start and stop times.

A program in MPEG is a collection of elements A program in MPEG is a collection of elements with a common time base only. That is a with a common time base only. That is a collection of elementary streams with same collection of elementary streams with same PCR_PID and referenced to the same PCR_PID and referenced to the same program_numberprogram_number

43

Virtual Channels & PCR TimingVirtual Channels & PCR Timing A conventional Broadcaster of a TV channel or A conventional Broadcaster of a TV channel or

service having one program would be composed of a service having one program would be composed of a series of “broadcaster programs” or events with the series of “broadcaster programs” or events with the samesame program_number and a common PCR_PID. program_number and a common PCR_PID.

In other words the PCR time base effectively creates a In other words the PCR time base effectively creates a virtual channel which may be associated with a single virtual channel which may be associated with a single or multiple program_numbers.or multiple program_numbers.

A TV channel having multiple programs would have A TV channel having multiple programs would have multiple program_numbers with either single or multiple program_numbers with either single or multiple PCR_PID between program streams.multiple PCR_PID between program streams.

NOTE : Services with different program_numbers may draw upon the same video as NOTE : Services with different program_numbers may draw upon the same video as with the case of multilingual services.with the case of multilingual services.

44

Decoding the ProgramDecoding the Program Decoding the correct program (ie “channel”) ?Decoding the correct program (ie “channel”) ?

Where there are several Transport Streams available Where there are several Transport Streams available to a decoder, in order to successfully demultiplex a to a decoder, in order to successfully demultiplex a program, the decoder must be notified of both the program, the decoder must be notified of both the transport_stream_id (to find the correct multiplex) transport_stream_id (to find the correct multiplex) and the program_number of the service (to find the and the program_number of the service (to find the correct program within the multiplex). correct program within the multiplex).

Note again the program here refers to the channel Note again the program here refers to the channel notnot the event or actual broadcast program.the event or actual broadcast program.

Now to the various main table purposes :Now to the various main table purposes :

45

PAT, PMT & CAT TablesPAT, PMT & CAT Tables PAT (Program Association Table)PAT (Program Association Table)

provides the link between the transport_stream_id, the provides the link between the transport_stream_id, the program_number and the program_map_id (PMT).program_number and the program_map_id (PMT).

PMT (Program Map Table)PMT (Program Map Table) when pointed to from the PAT, the PMT provides the when pointed to from the PAT, the PMT provides the

associated group of elements (video, audio etc) with associated group of elements (video, audio etc) with the program_number.the program_number.

CAT (Conditional Access Table)CAT (Conditional Access Table) provides the association between CA system(s) and provides the association between CA system(s) and

their EMM (Entitlement Management Messages) their EMM (Entitlement Management Messages) streams and any special parameters associated with streams and any special parameters associated with them.them.

46

DVB SI FeaturesDVB SI Features Data structured as several “Tables”Data structured as several “Tables” Structures use “fixed format” for essential data, Structures use “fixed format” for essential data,

and descriptors for optional or variable-length and descriptors for optional or variable-length data (similar to PSI)data (similar to PSI)

Efficient data transmissionEfficient data transmission Extensible while maintaining compatibilityExtensible while maintaining compatibility Support for “private” extensionsSupport for “private” extensions

Can provide standard EPG data-streamCan provide standard EPG data-stream ““Look and Feel” determined by receiver softwareLook and Feel” determined by receiver software

• Resident or DownloadedResident or Downloaded

47

SI Features: NITSI Features: NIT Network Information TableNetwork Information Table

Identification of transmission as a member of a group Identification of transmission as a member of a group of multiplexes - “Network”of multiplexes - “Network”

Network NameNetwork Name Tuning parameters with support for various delivery Tuning parameters with support for various delivery

media media List of additional frequencies for terrestrial transmissionList of additional frequencies for terrestrial transmission

Designed for simple transcoding of transport streamsDesigned for simple transcoding of transport streams

48

SI Features: SDT & BATSI Features: SDT & BAT Service Description TableService Description Table

Identifies all Service names and Service types in TSIdentifies all Service names and Service types in TS Linked ServicesLinked Services Pointer to MPEG Program in PSIPointer to MPEG Program in PSI

Service_id = MPEG Program NumberService_id = MPEG Program Number

Bouquet Association Table (Optional)Bouquet Association Table (Optional) Groupings of ServicesGroupings of Services May convey “logical channel number”May convey “logical channel number”

49

SI Features: EITSI Features: EIT Present/FollowingPresent/Following

Information on current and next eventsInformation on current and next events

Schedule (optional)Schedule (optional) Up to 64 days ahead - ordered by service and timeUp to 64 days ahead - ordered by service and time

Event InformationEvent Information Title, short descriptionTitle, short description Start time & durationStart time & duration Content classification & parental ratingContent classification & parental rating Longer text descriptionLonger text description Information on componentsInformation on components

50

SI Features: TDT,TOT, RSTSI Features: TDT,TOT, RST Time and Date TableTime and Date Table

Transmission of current time for automatic setting of Transmission of current time for automatic setting of receiver clockreceiver clock

Time Offset Table (optional)Time Offset Table (optional) Transmission of time offset by zone - both current, and next Transmission of time offset by zone - both current, and next

offset values, with date at which next occursoffset values, with date at which next occurs

Running Status Table (optional)Running Status Table (optional) Mechanism for signalling status transitions with greater Mechanism for signalling status transitions with greater

timing precisiontiming precision

51

Electronic Program Guide - EPGElectronic Program Guide - EPG

EPG (Electronic Program Guide)EPG (Electronic Program Guide) Combining primarily the EIT and the SDT, both the Combining primarily the EIT and the SDT, both the

time and description is provided to the viewer via time and description is provided to the viewer via some form of EPG ranging from “vanilla EPG’s”, some form of EPG ranging from “vanilla EPG’s”, simple “eye plate style” displays to full blown EPG’s, simple “eye plate style” displays to full blown EPG’s, either from Receiver manufacturers designs or either from Receiver manufacturers designs or downloaded EPG’s with GUI interfaces designed by downloaded EPG’s with GUI interfaces designed by the Networks.the Networks.

This information so constructed and displayed can be This information so constructed and displayed can be used to provide a Parental Guidance lock function used to provide a Parental Guidance lock function through PIN number access.through PIN number access.

52

Example EPG using DVB SIExample EPG using DVB SI

53

Example: Event DetailsExample: Event Details

54

Example: Selection by GenreExample: Selection by Genre

55

Example: Selection by GenreExample: Selection by Genre

56

Application Program Interface APIApplication Program Interface API

API (Application Programming Interface)API (Application Programming Interface)

some form of API must be used to allow the control by some form of API must be used to allow the control by

the viewer or installer of the decoder / receiver. The the viewer or installer of the decoder / receiver. The

API software provides the connection between the API software provides the connection between the

applications (eg. EPG) and the hardware.applications (eg. EPG) and the hardware.

Some API’s may employ MHEG-5 multimedia support Some API’s may employ MHEG-5 multimedia support

and Java programming language for EPG generation.and Java programming language for EPG generation.

CA in practice is reliant upon EPG’s and the API’sCA in practice is reliant upon EPG’s and the API’s..

57

DVB - Conditional AccessDVB - Conditional Access

CA (Conditional Access)CA (Conditional Access)

Access to the EMM (Entitlement Management Access to the EMM (Entitlement Management

Message) is provided by the CAT.Message) is provided by the CAT.

The EMM allows a single decoder to view the The EMM allows a single decoder to view the

program material which is scrambled via a DVB program material which is scrambled via a DVB

“common scrambling algorithm” by providing the key “common scrambling algorithm” by providing the key

to the code word which is involved in the scrambling. to the code word which is involved in the scrambling.

The code word is sent via the The code word is sent via the

ECM (Entitlement Control Message). ECM (Entitlement Control Message).

58

Typical Conditional Access SystemTypical Conditional Access System

59

A Future Digital System ConceptA Future Digital System Concept

HypermediaIntegrated Receiver

Decoder (IRD)

MMDS

Satellite

Terrestrial

Cable

B-ISDNXDSL CD, DVD

DVC

Broadcast Interactivity

60

VHF - Band IIIVHF - Band III

UHFUHF

DOPPLERDOPPLERSHIFTSHIFT((Hz)Hz)

140 140

300300

0000 10001000500500100100 200200 300300 400400 600600 700700 800800 900900

100100

5050

200200

250250

COFDM 2K, 3dB degradeCOFDM 2K, 3dB degrade

COFDM 2KCOFDM 2K

SPEED (Km/Hr)SPEED (Km/Hr)AIRCRAFTAIRCRAFTVehiclesVehicles

Over CitiesOver Cities

for currentfor currentimplementationsimplementations

ATSCATSCseesee separateseparate curvescurves

COFDM implementations will inherently handleCOFDM implementations will inherently handle post andpost and pre-ghostspre-ghosts equally within the selected guard interval.equally within the selected guard interval.

DTTB Systems Doppler Performance Limits

DTTB Systems Doppler Performance Limits

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Main Results - Lab TestsMain Results - Lab Tests C/N ATSC 4 dB better than DVB-T.C/N ATSC 4 dB better than DVB-T.

This Advantage offset by Poor Noise FigureThis Advantage offset by Poor Noise Figure DVB-T is better than ATSC for MultipathDVB-T is better than ATSC for Multipath ATSC is better than DVB-T for Impulse NoiseATSC is better than DVB-T for Impulse Noise ATSC cannot handle Flutter or Doppler EchoesATSC cannot handle Flutter or Doppler Echoes ATSC is very sensitive to Transmission system ATSC is very sensitive to Transmission system

impairments and IF translationimpairments and IF translation DVB-T is better at handling Co-channel PALDVB-T is better at handling Co-channel PAL DVB-T is better rejecting on channel interference DVB-T is better rejecting on channel interference

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