hybrid satellite-terrestrial mobile broadcasting...
TRANSCRIPT
Hybrid Satellite-TerrestrialMobile Broadcasting
Systems
Professor David CrawfordUniversity of Essex, UKden 12 Oktober 2007
Wireless Communication & Information KonferenzBerlin, Germany
Introduction
COFDM – explanation
Limitations: Echoes / SFN size
Doppler distortion
Spectrum
DVB-SH: Overview
Architectures
Trials
Conclusions
Contenders for Multimedia Broadcasting
DAB-IP UK, Scandanavia
DVB-H Europe, USA and Uruguay
T-DMB Korea, Europe
S-DMB Korea, China
ISDB-T Japan, Brazil
FLO USA, Asia
TDtv UK, Europe
MBMS Europe
DMB, MMB … China
CMMB (STiMi) China
DVB-SH Europe, USA} Hybrid
sat-terr.
GuardGuardIntervalInterval
UsefulUsefulPeriodPeriod
OFDM symbolOFDM symbol
OrthogonalOrthogonalCarrierCarrierSpacingSpacing
COFDM
TimeTime
freq
uenc
y
freq
uenc
y
256
512
1K1K
2K2K2K2K
4K4K4K
8k8K8K
5/6/7/8 MHz6/7/8 MHz5/6/7/8 MHz1,5 MHz
FLOISDBDVBDAB/DMB
Single Frequency Network Sizes
DVB-T vs DVB-H(8K - gi 1/4 - 16QAM 2/3 - MPE-FEC 3/4)
13,27 Mbps
0.0 dB
10.0 dB
20.0 dB
30.0 dB
40.0 dB
50.0 dB
0 Hz 1 Hz 10 Hz 100 Hz 1000 Hz
DVB-H @ FER 5%DVB-H @ MFER 5%DVB-T "Rayleigh"
470 MHz UHF Band IV (21)470 MHz UHF Band IV (21)
854 MHz UHF Band V (69)854 MHz UHF Band V (69)
1 km/h1 km/h
0,4 km/h0,4 km/h
2 km/h2 km/h
1 km/h1 km/h
7 km/h7 km/h
4 km/h4 km/h
23 km/h23 km/h
13 km/h13 km/h
69 km/h69 km/h
38 km/h38 km/h
230 km/h230 km/h
126 km/h126 km/h
689 km/h689 km/h
379 km/h379 km/hTU6TU6
Flat BehaviourFlat Behaviour
Until Max SpeedUntil Max Speed
Mobile Performances : “C/N versus Doppler”
DVB-HDVB-HMPE-FECMPE-FECGAIN :GAIN :
5 to 9 dB 5 to 9 dB (Mobile)(Mobile)
QPSK 1/2 (5 Mbps)QPSK 1/2 (5 Mbps)
16QAM 2/3 (13 Mbps)16QAM 2/3 (13 Mbps)
DVB-TDVB-TMobileMobilePenaltyPenalty
6 to 12 dB6 to 12 dB
DVB-H GainDVB-H GainAreaArea
DVB-HDVB-HMPE-FECMPE-FECGAIN :GAIN :
2 to 5 dB 2 to 5 dB (Pedestrian)(Pedestrian)
64QAM 2/3 (20 Mbps)64QAM 2/3 (20 Mbps)
Christian AndreasChristian Andreas
DOPPLERDOPPLER(1803-1853)(1803-1853)
)cos(!""=#C
fVf
rf
D
T
EIRP
Suitability of Spectrum Bands for Mobile TV
174 470 854 1452 1492 1550 2450 2600 2700 3000
Band III Bands IV, V L Band ISM Band S Band MHz
DAB Mil TV ATV DTV GSM Mil DAB DECT UMTS 4G Sat µwave
Mob Radio (HDTV) GSM
TETRA
LW
MW
FM
EIRP
Satellite-
terrestrial
VHF UHF
Comparison of Frequencies of Operation
High
S-Band
High
L-band
High
UHF
Low
VHF
SpectrumDopplerTransmnCapacityHandsetFreq
= worst
= best
9 TVchannels
< 27 TVchannelsunlimited
channels(unicast)
2170-2200GHz MSS band1452-1492GHz T-/S-DAB band
2G/3G
Typical Hybrid System
1.90-2.17GHz UMTS band
DVB-SH opens new bands for DVB broadcast
Electric Waves
RadioWaves
Infra-RedVisibleLight
UltraViolet
X-RaysGamma
RaysCosmicRays
Radio Spectrum
LongWaveRadio
MediumWaveRadio
ShortWaveRadio
IIFM
Radio
IIITV
(VHF)
IV & VTV
(UHF)
KuBand
KaBand
TerrestrialTerrestrialOnlyOnly
SatelliteSatelliteOnlyOnly
HybridHybridTerrestrialTerrestrial
&&SatelliteSatellite
L & SBands
CBand
10 100 1000 10000 100000 1000000 10000000 100000000 1000000000
3 30 30 300300 3
LF SHF EHF Decreasing CoverageIncreasing Bandwidth
Increasing CoverageDecreasing Bandwidth HFMF
30
VHF
3300
UHF
kHz MHz GHz
MULTIMEDIA : CONTENTS / APPLICATIONS / SERVICESMULTIMEDIA : CONTENTS / APPLICATIONS / SERVICES
IP: TRANSPORT LayerIP: TRANSPORT Layer
DVB-IPDC : IP DVB-IPDC : IP DataCastDataCast
DVBDVB
Digital TV ServicesDigital TV Services
TSTS
DVB-TDVB-T
IPIP
TSTS
DVB-HDVB-H
IP: TRANSPORT LayerIP: TRANSPORT Layer
DVB-IPDC : IP DVB-IPDC : IP DataCastDataCast
IPIP
TSTS
DVB-SHDVB-SH
TSTS
+
DVB Family for serial digital and IP streamed services
DVB-SH Hybrid Network
Satellite
Terrestrial Repeater(s)
Terminals
SatelliteEarth
Station
SH-A : OFDMSH-B : TDM Modulations
In S-Band
SH-A : OFDMSH-B : OFDMModulations
In S-BandPrimaryPrimary
DistributionDistributionNetworkNetwork
IPDCServices
IPDCHead-end
Problem of Coverage in Urban Areas
DVB-SH Coverage
Dense Urban and Urban:Cellular TerrestrialRepeaters mapped with 3GTopology
Efficient indoor penetrationsimilar to voice service
Suburban:Trade-off/Mixed satelliteandrepeaters coverage
Fit to indoor penetrationobjective and satelliteconfiguration
Rural:Satellite coverage onlyTurbo FEC decreases C/Nthreshold and long interleaverhelps while non-line-of-sight.
DVB-SH – Full Network Overview
System Architecture
Comparison of System Capacities
DVB-SHDVB-SHIn S-bandIn S-band
Birth CertificateName : Satellite Services to HandHeldsNick Name : DVB-SHDate of Birth : 14 February 2007 Status : DVB Blue Books published (www.dvb.org)
. A110 (SH system) . A111 (SH waveform)ETSI standardisation in progress
Frequency bands : Below 3 GHz (1..3 GHz)Signal Bandwidth : 1.75 MHz, 5 / 6 / 7 / 8 MHz
Waveform : SH-A = OFDM / OFDM (Sat / Terrestrial) SH-B = TDM / OFDM (Sat / Terrestrial)
OFDM Waveform : Multi-Carrier (OFDM) FFT sizes : 1K / 2K / 4K / 8KGuard Interval : 1/4, 1/8, 1/16, 1/32
Constellations : (OFDM) QPSK, 16QAM, Hierarch (QPSK in QPSK) (TDM) QPSK, 8PSK, 16APSK, Code Rates : 1/5, 2/9, 1/4, 2/7, 1/3, 2/5, 1/2, 2/3
Channel Encoder : Common for the two waveforms, . Input Adaptation Encapsulation in EFRAME of 12282 bits
Insertion of EFRAME header & CRC16 . Scrambling over EFRAME . FEC 3GPP2 TurboCode over 12282 b i/p blocs . Interleavers DVB-T bit interleaver (freq interleaver),
DVB-SH Convolutional Block interleaver,. Forney Type with 48 branches
(Rx : class-1) . ~200 ms (16QAM) / ~300 ms (QPSK) (Rx : class-2) . Up to 10 seconds
Conclusions
Hybrid satellite-terrestrial mobile broadcasting systems are being implemented in: Europe: Eutelsat W2A satellite covering Fr, Ge, It, Po, Sp, UK. N America: ICO G1 satellite covering US, Ca. China: 2 satellites to be launched covering Olympic cities.
Spectrum is available for satellite-terrestrial use; it is harmonised and under-utilised: S-band: 30 MHz in the band 2170-2200 MHz (Eu) L-band: 40 MHz in the band 1452-1492 MHz (Eu) S-band: 25 MHz in the band 2635-2660 MHz (Ch)
There can be equipment cost savings if the satellite and terrestrial segments areclose in frequency (eg. filters, amplifiers etc).
DVB-SH can complement existing DVB-H deployments. Large region coverage willbe achieved by the satellite footprint. Terminals will be dual mode – receivingDVB-SH via the L-/S-bands and DVB-H at UHF. The use of DVB IP Datacastspecifications in both systems will ensure compatability after demodulation.
Danke!
Thank You
Professor David Crawford University of Essex, UK
tel: +44-1206-874495
email: [email protected]