broadcast systems

8/8/2019 Broadcast Systems

1/19

Prof.Dr.-Ing.JochenSchiller,http://www.jochensc

hiller.de/

MCSS02

6.1

Mo

bileCom

municat

ions

Chapter6:Bro

adcastS

ystems

Unidirectionaldistributionsystem

s

DAB

architecture

DVB

Container

High-speedInternet


2/19


hiller.de/

MCSS02

6.2

Unidirec

tionaldistributionsystems

A

symmetriccomm

unicationenviron

ments

bandwidthlim

itationsofthetran

smissionmedium

dependsonapplications,typeo

finformation

examples

wirelessn

etworkswithbasestationandmobileterm

inals

client-serv

erenvironments(disklessterminal)

cableTVwithset-topbox

informatio

nservices(pager,SM

S)

S

pecialcase:unid

irectionaldistribu

tionsystems

highbandwid

thfromservertoc

lient(downstream)

,butnobandwidth

vice

versa(upstre

am)

problemsofunidirectionalbroadcastsystems

asendercanoptimizetransmittedinformationonlyforonegroupof

users/term

inals

functionsneededtoindividualiz

epersonalrequirements/applications


3/19


hiller.de/

MCSS02

6.3

Unidirec

tionaldistribution

service

provider

service

user

sender

receiver

receiver

receiver

. . .

unidire

ctional

distribution

medium

AA

AA

A

A

A

B

BB B

optimized

forexpected

acces

spattern

ofa

llusers

individua

laccess

patternof

oneuser


4/19


hiller.de/

MCSS02

6.4

S

ender

cyclicrepetitionofdatablocks

differentpatternspossible(optimizationpossibleo

nlyifthecontentis

known)

R

eceiver

useofcachin

g

cost-base

dstrategy:whatarethecostsforauser(w

aitingtime)ifadata

block

hasbeen

requestedbutiscurrentlynotcached

applicationandcachehavetoknowcontentofdata

blocks

andaccesspatternsofuserto

optimize

Structur

ingtransmissions-broadcastdisks

A

B

C

A

B

C

flatdisk

A

A

B

C

A

A

skeweddisk

A

B

A

C

A

B

multi-disk


5/19


hiller.de/

MCSS02

6.5

DAB:DigitalAudioBroadcasting

Mediaaccess

COFDM(CodedOrthogonalFrequencyDivisio

nMultiplex)

SFN(Sin

gleFrequencyNetwork)

192to15

36subcarrierswithina1.5MHzfrequ

encyband

Frequencies

firstphas

e:oneoutof32fre

quencyblocksfor

terrestrialTV

channels

5to12(174-230

MHz,5A-12D)

secondp

hase:oneoutof9

frequencyblocksintheL-band

(1452-14

67.5MHz,LA-LI)

Sendingpower:6.1kW(

VHF

,120km)or

4kW(

L-ban

d,30km)

Date-rates:

2.304Mbit/s(net

1.2to1.536Mbit/s)

Modulation:

Differential4-phasemodulation(D-QPSK)

Audiochannelsperfrequenc

yblock:typ.6,m

ax.192kbit/s

Digitalservices:0.6-16kbit/s(PAD),24kbit/

s(NPAD)


6/19


hiller.de/

MCSS02

6.6

DABtra

nsportmechanisms

M

SC(MainServic

eChannel)

carriesalluserdata(audio,multimedia,...)

consistsofC

IF(CommonInterleavedFrames)

eachCIF55296bit,every24m

s(dependsontran

smissionmode)

CIFcontains

CU(CapacityUnits),64biteach

F

IC(FastInformationChannel)

carriescontrolinformation

consistsofFIB(FastInformationBlock)

eachFIB256

bit(incl.16bitchecksum)

definesconfigurationandcontentofMSC

S

treammode

transparentd

atatransmissionw

ithafixedbitrate

P

acketmode

transferaddr

essablepackets


7/19


hiller.de/

MCSS02

6.7

Transmissionframe

synchronization

channel

S

C

mainservice

channel

FIC

MSC

null

symbol

phase

refere

nce

symbol

data

symbol

data

symbol

da

ta

sym

bol

......

symbol

Tu

framedurationTF

guard

intervalTd

L

0

0

1

2

L-1

1

L

fastinform

ation

chann

el

FIC


8/19


hiller.de/

MCSS02

6.8

DABsender

Trans-

mitter

Trans-

mission

Multi-

plexer

MSC

Multi-

plexer

ODFM

Packet

Mux

Channel

Coder

Audio

Encoder

Channel

Coder

DABSignal

Service

Information

FIC

Multiplex

Information

D

ata

S

ervices

A

udio

S

ervices

RadioFrequency

FIC:FastInformation

Channel

MSC:MainServiceC

hannel

OFDM:OrthogonalF

requencyDivisionMultiplexing

1.5MHz

f

carriers


9/19


hiller.de/

MCSS02

6.9

DABrec

eiver

Packet

Demux

Audio

D

ecoder

Channel

Decoder

Indep

endent

DataService

Audio

Service

Controller

Tuner

ODFM

Demodulator

UserInterface

FIC

ControlBu

s

(p

artial)

MSC


10/19


hiller.de/

MCSS02

6.10

Audiocoding

Goal

audiotransmissionalmostw

ithCDquality

robustag

ainstmultipathpro

pagation

minimald

istortionofaudios

ignalsduringsigna

lfading

Mechanisms

fullydigitalaudiosignals(PCM,16Bit,48kHz,stereo)

MPEGco

mpressionofaudiosignals,compres

sionratio1:10

redundan

cybitsforerrorde

tectionandcorrect

ion

bursterro

rstypicalforradio

transmissions,the

reforesignal

interleaving-receiverscannowcorrectsingle

biterrorsresulting

frominterference

lowsymb

ol-rate,manysymbols

transmissionofdigitaldata

usinglongsymbolsequences,separated

by

guard

spaces

delayedsymbols,e.g.,reflection,stillremainwithintheguardspace


11/19


hiller.de/

MCSS02

6.11

Bitratemanagement

aDABense

mblecombinesa

udioprogramsa

nddataservices

withdifferen

trequirementsfo

rtransmissionqualityandbitrate

s

thestandardallowsdynamic

reconfigurationo

ftheDAB

multiplexing

scheme(i.e.,du

ringtransmission

)

dataratesc

anbevariable,D

ABcanusefree

capacitiesforoth

er

services

themultiplexerperformsthis

kindofbitratem

anagement,

therefore,additionalservices

cancomefromdifferentproviders


12/19


hiller.de/

MCSS02

6.12

Exampleofareconfiguration

D1

D2

D3

D4

D5

D6

D7

D8

D9

Audio1

192kbit/s

PAD

Audio2

192kbit/s

PAD

Audio3

192kbit/s

PAD

Audio4

160kbit/s

PAD

Audio5

160kbit/s

PAD

Audio6

128kbit/s

PAD

DAB-Multiplex

D1

D2

D3

D4

D5

D6

D7

D8

D9

Audio1

192kbit/s

PAD

Audio

2

192kb

it/s

PAD

Audio3

128kbit/s

PAD

Audio

4

160kb

it/s

PAD

Audio5

160kbit/s

PAD

Audio

7

96kbit/s

PAD

DAB-Multiplex-

reconfigured

Audio8

96kbit/s

PAD

D10

D11


13/19


hiller.de/

MCSS02

6.13

Multime

diaObjectTra

nsferProtocol(MOT)

P

roblem

broadrange

ofreceivercapabilities

audio-onlyd

eviceswithsingle/multiplelinetextdisplay,additionalco

lor

graphicdisp

lay,PCadapterse

tc.

differenttypesofreceiverssho

uldatleastbeable

torecognizeallkindsof

programass

ociatedandprogramindependentda

taandprocesssom

eof

it

S

olution

commonsta

ndardfordatatran

smission:MOT

importantforMOTisthesuppo

rtofdataformatsusedinothermultim

edia

systems(e.g.,onlineservices,

Internet,CD-ROM)

DABcanthe

reforetransmitHT

MLdocumentsfromtheWWWw

ithv

ery

littleaddition

aleffort


14/19


15/19


hiller.de/

MCSS02

6.15

DigitalV

ideoBroadcasting

1991foundationoftheELG(EuropeanLaunchingGroup)

goal:developm

entofdigitaltelevisioninEurope

1993renaming

intoDVB(DigitalVideoBroadcas

ting)

goal:introductionofdigitaltelevisionbasedon

satellitetran

smission

cablenetwo

rktechnology

lateralsoterrestrialtransmissio

n

SDTV

EDTV

HDTV

MultimediaPC

B-

ISDN,ADSL,etc.D

VD

,etc.

Terrestrial

Receiver

Cable

Multipoint

Distribution

System

Satellites

DVB

Digit

al

Vid

eo

Broa

dcas

ting

Integrated

Receiver-D

ecoder


16/19


hiller.de/

MCSS02

6.16

DVBCo

ntainer

DVBtransmits

MPEG-2contain

er

highflexibilityforthetransm

issionofdigitaldata

norestric

tionsregardingthe

typeofinformation

DVBServiceInformationsp

ecifiesthecontent

ofacontainer

NIT(N

etworkInformationT

able):liststheservic

esofaprovider,

containsadditionalinforma

tionforset-topboxes

SDT(ServiceDescriptionT

able):listofnamesa

ndparametersforea

ch

servic

ewithinaMPEGmultiplexchannel

EIT(E

ventInformationTab

le):statusinformationaboutthecurrent

transm

ission,additionalinformationforset-topb

oxes

TDT(

TimeandDateTable

):Updateinformation

forset-topboxes

multimedia

databroadcasting

MPEG-2/D

VB

container

singlechannel

highdefinitiontelevision

MPEG-2/DVB

container

H

DTV

multiplechannels

standarddefinitio

n

MPEG-2/DVB

container

SDTV

multiplechannels

enhanceddefinition

MPEG-2/DVB

container

EDTV


17/19


hiller.de/

MCSS02

6.17

Example:high-speedInternetacces

s

Asymmetricda

taexchange

downlink

:DVBreceiver,da

tarateperuser6-38Mbit/s

returnch

annelfromuserto

serviceprovider:e

.g.,modemwith33

kbit/s,IS

DNwith64kbit/s,DSLwithseveral1

00kbit/setc.

DVB-Sadapter

PC

Internet

TCP/IP

leasedline

service

provider

information

provider

satellite

provider

satellitereceiver

DVB/MPEG2m

ultiplex

simultaneousto

digitalTV


18/19


hiller.de/

MCSS02

6.18

Converg

enceofbroad

castingandm

obilecomm.

D

efinitionofintera

ctionchannels

Interacting/controllingbroadcastviaGSM,UMTS

,DECT,PSTN,

E

xample:mobileInternetservicesusingIPoverGSM/GPRSorUMT

Sas

interactionchannelforDAB/DVB

mobile

termina

l

DVB-T,DAB

(T

VplusIPdata)

GS

M/GPRS,

UM

TS

(IP

data)

MUX

Internet

TVbroadcaster

ISP

m

obileoperator

TV

data

bro

adcast

intera

ctio

n

channels


19/19


hiller.de/

MCSS02

6.19

Compar

isonofUMTS,DABandDVB

UMTS

DAB

DVB

Spectrumbands

(dependson

national

regulations)[MHz

]

2000(terrestria

l),

2500(satellite)

1140-1504,

220-228(UK)

130-260,

430-862(UK)

Regulation

Telecom,

licensed

Broadcast,

licensed

Broadcast,

licensed

Bandwidth

5MHz

1.5MHz

8MHz

Effective

throughput

30-300kbit/s

(peruser)

1.5Mbit/s

(shared)

5-30Mbit/s

(shared)

Mobilitysupport

Lowtohigh

Veryhigh

Lowtohigh

Application

Voice,data

Audio,push

Internet,images,

lowres.video

Highres.video,

audio,pushInternet

Coverage

Localtowide

Wide

Wide

Deploymentcost

forwidecoverage

Veryhigh

Low

Low

broadcast systems

Documents