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TECHNOLOGIES RADIO & SIGNAL UNIT 1
THALES COMMUNICATIONS
New InternationalDigital audio-broadcastingstandard, voice coding and amateur radio applications
Cédric DEMEURE
Hamvention, Dayton, Ohio, USAMay 19 2002
TECHNOLOGIES RADIO & SIGNAL UNIT 2
THALES COMMUNICATIONS
Summary
Digital Radio Mondiale
HF High data rate Modem
Speech coders
Digital Amateur Radio 3 kHz demonstrator
TECHNOLOGIES RADIO & SIGNAL UNIT 3
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DRMWorld-wide consortium to promote a unique standard for digital LF, MF & HF audio-broadcasting
Members include :Broadcasters and Broadcasting associationsNetwork OperatorsResearch InstitutesComponent, Receiver and Transmitter ManufacturersRegulatory and Standardisation Authorities
Key features:Worldwide standard Better audio quality Simple to use receiversLow cost equipment Text message Data applicationsProvide future enhancements
TECHNOLOGIES RADIO & SIGNAL UNIT 4
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DRM
73 DRM-Members from 27 countries, Feb 2002
TECHNOLOGIES RADIO & SIGNAL UNIT 5
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DRM Members
See www.drm.org for more details
USAHarris BroadcastInternational Broadcasting Bureau Continental Electronics CorporationSangean America Inc.Technology for Communications International
Others :BBC, Sony, Bosch, Thales, NHK, RFI, DW, JVC, Telefunken ...
TECHNOLOGIES RADIO & SIGNAL UNIT 6
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ETSI
DRM STANDARDISATION PROCESS
ARIB
DRM
ITU
ISOMPEG
National delegation
IEC
JRG ITU/IEC
ITUSector
member
Other regionalstandardisation bodies
TECHNOLOGIES RADIO & SIGNAL UNIT 7
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DRM: Different transmission modes (1)System flexibility in Digital
4.5 kHz Carrier Groupcontaining FAC cells
4.5 kHz additionalGroup of Carriers
4.5 kHz
9 kHz
18 kHz
Frequency
Spectrum occupancyfor 4.5 kHz channeling
5 kHz Carrier Groupcontaining FAC cells
5 kHz additionalGroup of Carriers
5 kHz
10 kHz
20 kHz
for 5 kHz channeling
FAC: Fast Access Channel
TECHNOLOGIES RADIO & SIGNAL UNIT 8
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DRM: Different transmission modes (2)System flexibility in Simulcast
AM DSB signal
AM VSB signal
Group of carriers containing FAC cells
Group of carriers
Additionalpossibilitiesin HF bands
only
All bands
TECHNOLOGIES RADIO & SIGNAL UNIT 9
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DRM ModemA highly efficient and flexible OFDM modem:
very high spectrum efficiency: up to 3 bit/Hz/smulti-modes related to propagation and channel bandwidthOFDM preferred over single carrier because of flexibility
Various transmission modes adapted to different Propagation types
Mode A: Gaussian channels, with minor fading LW and MW during daytime
Mode B: Time and frequency selective channels, with longer delay spread: SW and MW nighttime
Mode C: Time and frequency selective channels, with greaterdoppler spread: bad SW channels
Mode D : Very robust mode
TECHNOLOGIES RADIO & SIGNAL UNIT 10
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DRM Modem (3)
Frequency Reference
Time Reference
Gain Reference
Remote Control
Useful Symbol15
50
75
10
20
30
40
50
60
70
80
90
100
110
-20
-10
-30
120
130
-40
1.5 kHz
3 kHz
1.5 kHz
DCcomponent
33 1/3 Hz
Frame: 8 OFDM Symbols, 288 msSymbol: 30 ms Useful Symbol + 6 ms Guard Interval
0
(old version)
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System architecture: TX side
SDC (ServiceDescription Channel)
FAC (FastAccess Channel)
DataStream
AudioSignal
DRMTransmission
Signal
Normal Protection
HighProtection
EnergyDispersal
EnergyDispersal
Cha
nnel
Enco
der
OFDMSignal
Generator
Mod
ulat
or
OFD
M C
ell M
appe
r
MSC
PilotGenerator
EnergyDispersal
FAC
AACStereo
AACMono
NarrowBandCELP
NarrowBandCELP
EnergyDispersal
SDC
Mul
tiple
x
SpectralBand
ReplicationSBR
Higher bit-ratemax: 48 kbit/s
Pre-coder
Pre-coder
Pre-coderNormal Protection
High Protection
ChannelEncoder
ChannelEncoder
AudioSuper
Framing
Standard Mode
20 kbit/s
UltraRobustMode
10 kbit/s
Low bitrate Mode
8 kbit/s
CellInterleaver
TECHNOLOGIES RADIO & SIGNAL UNIT 12
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DRM Experimental System HardwareGeneral functional block Diagram
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DRM Experimental system
MMI transmit MMI receive
Modem Analysis tool Propagation Analysis tool
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System Validation : tests
MW Validation:- 1 transmmission site
- 5 receiving sites
Large investigation : most critical paths validated
SW Validation:- 5 transmmission sites and 17 receiving sites
- All SW frequency bands: 5MHz to 25 MHz
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Compatibility with existing AM Services
Spectrum at distant receiving site
with Analogue AM DSB signal
with Digital DRM signal
Non-modified250 kW PSM SW TX Output Spectrum
at 80 kW rmsdigital output power
TECHNOLOGIES RADIO & SIGNAL UNIT 16
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DRM Status: receiver chipset & Standard
Various projects to develop chip-sets
Eureka (European Commission sponsored program) DIAM:Atmel, Bosch, Sony, TDF, Thales ...2 chips (1 analog RF, 1 digital), direct conversion receiverForecast Availability: end 2003
DRM the only worldwide ITU standard at SW DRM and IBOC ITU standard at LW and MWIBOC standard at FM
Work proposed to extend DRM to FM bands
TECHNOLOGIES RADIO & SIGNAL UNIT 17
THALES COMMUNICATIONS
Voice coders: Standards and Performances
Bit rate (bits/s)1k 2k 4k 8k 16k 32k 64k
IndicativeQuality (MOS)
1
2
3
4
5G711(72)
G726(88)
ST4209(83)
G 728(92)
FS 1016(90)
G 729(96)
ST 4479(93)
ST 4198(87)
STG 4591MELP (02)
LPC 10(83)
GSM(87)
G 723-1CELP (96)
HSX(96)
Waveform codersParametric coders Hybrid coders
WBLBR
VLBR
Research codersExisting products
TECHNOLOGIES RADIO & SIGNAL UNIT 18
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Voice coders: quality
1
2
3
4
5
1980 1990 2000
IndicativeQuality (MOS)
G.711(64 kb/s) G.721
(32 kb/s) G.729(8 kb/s)
G.728(16 kb/s)
STG 4198LPC (2,4 kb/s)
STG4591 (2,4 kb/s1.2 kb/s)
Consumer quality
Minimum qual.for high cost application
Minimum qual.For low cost application
1970
G.xxx(4 kb/s)
HSX(2,4 kb/s)
2010
TECHNOLOGIES RADIO & SIGNAL UNIT 19
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Other low rate voice coders
ITU 4 kbits/s : no selection yet between the various proponents
DVSI : proprietary format (IMBE and AMBE: 2 to 9.6 kbits/s) mainly chosen for satellite communications systems (Inmarsat), Iridium and APCO 25
Texas MELP : basis for the STG 4591 Stanag
Except for ITU 4kbits/s, all have rather high processing delay implying long PTT return time
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Amateur Radio Demonstrator
Adaptation of the DRM reference receiver for 3 kHz channels
Push-to-talk
Various modes according to :Voice coder rate : 1200, 2400, 3200 bits/s (4000-4800 pending)Modem robustnessChoice will be made during lab and fields experiments
100% PC based for simple integrationFull demonstrator working with Ten-Tec and Kenwood off-the-self transceiversAcross the Atlantic tests planned for 2002 with ARRL
TECHNOLOGIES RADIO & SIGNAL UNIT 21
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MMIin transmit
mode
TECHNOLOGIES RADIO & SIGNAL UNIT 22
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MMIin receive
mode
TECHNOLOGIES RADIO & SIGNAL UNIT 23
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CONCLUSIONS
DRM World-wide standard is a good technology basisfor Ham
Narrow band, PTT mode easily derived for HF Ham use
Available low bit rate vocoder quality reached acceptable quality
ARRL plans lab tests then trans-atlantic tests in 2002
TECHNOLOGIES RADIO & SIGNAL UNIT 24
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Thank you for your attention
Questions ??
TECHNOLOGIES RADIO & SIGNAL UNIT 25
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TECHNOLOGIES RADIO & SIGNAL UNIT 26
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Australia: FARBChina: Academy of Broadcasting ScienceCanada: Radio Canada International, Nautel LtdCzech R. HFCCCroatia RIZEgypt: Egyptian Radio and Television UnionEcuador: ESPOL, HCJBFrance: Atmel, CCETT, Europe 1, Radio France, Radio France Int., TDF, ThalesFinland: Kymenlaakso PolytechnicGermany: APR, Digitalrundfunk Sachsen Anhalt, DLM, DTAG, DW, DLR, FHG, IRT, Micronas, Robert
Bosch, Sony Intern., SWR, Telefunken Sendertechnik,, U. of Hanover, U. of Merseburg, U. of Ulm, VPRT
Hungary: Communication Authority, Antenna HungariaIndia: All India RadioItaly: RAIJapan: Hitachi Kokusai, JVC, NHKLuxembourg Broadcasting Centre Europe (RTL-CTL)Malaysia: ABUNetherlands: Nozema, Radio Nederland WereldomroepNigeria: Voice Of NigeriaNorway: TelenorNew Zealand: Radio NZ Int.Russia: Main Centre for Control of Broadcasting Networks and the Voice of RussiaSpain: Retevision, Universidad del Pais VascoSweden: Coding Technologies, Radio Sweden Int., TERACOM SE, Factum Electronics ABSwitzerland: EBU, ITU, ICRCTunesia: Arab State Broadcasting UnionUK: BBC, Christian Vision, LSI Logic, Merlin Com. Int., Qinetiq Ltd, Roke Manor Research Ltd.,
RadioScapeUSA: Continental Electronics Corp., Harris Corp., Sangean America, TCI, IBB/VOA, NASB
TECHNOLOGIES RADIO & SIGNAL UNIT 27
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DIAM ChipsetR
F An
alog
ueFr
ont-E
nd
DDC1
Switch Matrix
DDC2FM input
AM input
RF Digital Front-End
InitialSynchro
SymbolsDemodulation
Narrow-band jammerrejection
MLC decoder: control part(SW)
Demux
Audiodecoders
MMI anddata services
MLC decoder:Viterbi decodingprocessor (HW)
Audiooutput
Audiointerface
Hostprocessor
USB (or other)interface
Ext. datamem.
Ext. datamem.
Ext. prog.mem.
Internalcontrols and
configurations
8 Mbit SRAM
4 Mbit SRAM
8 Mbit SRAM
2 Mbit Flash
I-Cache8 kbytes
Ext. prog.mem.
2 Mbit Flash
DMA
AHB
APB bridgeAPB bus
D-Cache8 kbytes
D-TCM64 kbytes
I-TCM32 kbytes
ANALOGCHIP
DIGITAL CHIP
TECHNOLOGIES RADIO & SIGNAL UNIT 28
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Demonstrator Description
Can transmit at the same time vocoded voice + data(text message, text files, image files...)
available HSX vocoders : 1200 b/s, 2400 b/s, 3200 b/s(easy addition of other vocoders)
Can receive both DRM and SSBSSB : audio ouput is the SSB audioDRM : audio output is the vocoder output. In this case, also displays frame error rate, frequency offset, estimated SNR, estimated channel impulseresponse (in 3D representation)
3 degrees of protection :GND (Ground-wave) for short distance communicationSKY (Sky Wave) for long distanceROB (Robust) for difficult conditions
Choice between short and long interleaving
TECHNOLOGIES RADIO & SIGNAL UNIT 29
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Demonstrator Main Features
A simple hardware interfacing system with Radio-Amateur transceivers
levels adaptationsPush-To-Talk detectionan adjustable VOX systemreceiving level monitoring (if available)
Easy personalisationone editable text file defines the preferred starting optionsone additional editable text file (Settings.cmd) allows adjusting other parameters (thresholds, gains, squelch level...)
TECHNOLOGIES RADIO & SIGNAL UNIT 30
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Other features
Automatic re-programming of the receiver according to thecurrently received messageIntegrated auto-testSophisticated channel simulator (for checking performances in terms of SNR, frequency offset, channel severity)PTT testMonitoring level testTransmission of a pure tone instead of the DRM signalLocal vocoder auto-test
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