TECHNOLOGIES RADIO & SIGNAL UNIT

New International Digital audio-broadcasting standard, voice coding and amateur radio applications Cédric DEMEURE Hamvention, Dayton, Ohio, USA May 19 2002

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Summary

z Digital Radio Mondiale z HF High data rate Modem z Speech coders z Digital Amateur Radio 3 kHz demonstrator

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DRM z World-wide consortium to promote a unique standard for

digital LF, MF & HF audio-broadcasting z Members include : Î Broadcasters and Broadcasting associations Î Network Operators Î Research Institutes Î Component, Receiver and Transmitter Manufacturers Î Regulatory and Standardisation Authorities z Key features: Î Worldwide standard

Î Better audio quality

Î Simple to use receivers

Î Low cost equipment

Î Text message

Î Data applications

Î Provide future enhancements

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DRM

73 DRM-Members from 27 countries, Feb 2002 THALES COMMUNICATIONS

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DRM Members z See www.drm.org for more details z USA Î Harris Broadcast Î International Broadcasting Bureau Î Continental Electronics Corporation Î Sangean America Inc. Î Technology for Communications International z Others : Î BBC, Sony, Bosch, Thales, NHK, RFI, DW, JVC, Telefunken ...

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DRM STANDARDISATION PROCESS ISO MPEG

DRM

IEC ITU Sector member

National delegation

JRG ITU/IEC

ETSI ARIB Other regional standardisation bodies

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ITU

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DRM: Different transmission modes (1) System flexibility in Digital Frequency

4.5 kHz Carrier Group containing FAC cells 4.5 kHz

5 kHz

4.5 kHz additional Group of Carriers 9 kHz

10 kHz

5 kHz Carrier Group containing FAC cells 18 kHz

20 kHz

5 kHz additional Group of Carriers

Spectrum occupancy for 4.5 kHz channeling for 5 kHz channeling FAC: Fast Access Channel THALES COMMUNICATIONS

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DRM: Different transmission modes (2) System flexibility in Simulcast

All bands

AM DSB signal AM VSB signal Group of carriers containing FAC cells Group of carriers

Additional possibilities in HF bands only THALES COMMUNICATIONS

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DRM Modem z A highly efficient and flexible OFDM modem: Î very high spectrum efficiency: up to 3 bit/Hz/s Î multi-modes related to propagation and channel bandwidth Î OFDM preferred over single carrier because of flexibility z Various transmission modes adapted to different

Propagation types Î Mode A: Gaussian channels, with minor fading LW and MW

during daytime Î Mode B: Time and frequency selective channels, with longer delay spread: SW and MW nighttime Î Mode C: Time and frequency selective channels, with greater doppler spread: bad SW channels Î Mode D : Very robust mode THALES COMMUNICATIONS

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DRM Modem (3) 130 120

1.5 kHz

110 100

33 1/3 Hz

90 80

Frequency Reference

70

Time Reference

60

Gain Reference

50

75

50

3 kHz

40

Remote Control

30

Useful Symbol

20

15

10 DC component

0

(old version)

-10

1.5 kHz

-20 -30 -40

Symbol: 30 ms Useful Symbol + 6 ms Guard Interval Frame: 8 OFDM Symbols, 288 ms

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System architecture: TX side

Mode 8 kbit/s

Data Stream FAC (Fast Access Channel) SDC (Service Description Channel)

Channel Encoder

Energy Dispersal

MSC

High Protection

Pilot Generator

Normal Protection

Pre-coder

High Protection

FAC Pre-coder

Energy Dispersal

Channel Encoder

SDC Pre-coder

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Energy Dispersal

DRM Transmission Signal

Cell Interleaver

Channel Encoder

OFDM Signal Generator

Modulator

Ultra Robust Mode 10 kbit/s

Narrow Band CELP Low bitrate Narrow Band CELP

Energy Dispersal

Audio Super Framing

OFDM Cell Mapper

Audio Signal

AAC Mono

Standard Mode 20 kbit/s

Spectral Band Replication SBR

Normal Protection

Multiplex

AAC Stereo

Higher bit-rate max: 48 kbit/s

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DRM Experimental System Hardware General functional block Diagram

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DRM Experimental system

MMI transmit

Modem Analysis tool THALES COMMUNICATIONS

MMI receive

Propagation Analysis tool

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System Validation : tests

MW Validation: - 1 transmmission site - 5 receiving sites

SW Validation: - 5 transmmission sites and 17 receiving sites - All SW frequency bands: 5MHz to 25 MHz

Large investigation : most critical paths validated THALES COMMUNICATIONS

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Compatibility with existing AM Services Non-modified 250 kW PSM SW TX Output Spectrum

Spectrum at distant receiving site

with Analogue AM DSB signal

at 80 kW rms digital output power with Digital DRM signal THALES COMMUNICATIONS

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DRM Status: receiver chipset & Standard z Various projects to develop chip-sets z Eureka (European Commission sponsored program) DIAM: Î Atmel, Bosch, Sony, TDF, Thales ... Î 2 chips (1 analog RF, 1 digital), direct conversion receiver Î Forecast Availability: end 2003 z DRM the only worldwide ITU standard at SW z DRM and IBOC ITU standard at LW and MW z IBOC standard at FM z Work proposed to extend DRM to FM bands THALES COMMUNICATIONS

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Voice coders: Standards and Performances Research coders Existing products

Indicative Quality (MOS) 5

HSX (96)

STG 4591 MELP (02)

WBLBR

2

G 728 (92)

G 723-1 CELP (96)

4 3

G 729 (96)

VLBR ST 4198 (87) ST 4479 (93)

FS 1016 (90)

GSM (87)

G726 (88)

G711 (72)

ST4209 (83)

LPC 10 (83)

1

1k

2k

Parametric coders THALES COMMUNICATIONS

4k

8k Hybrid coders

16k

32k

64k

Waveform coders

Bit rate (bits/s)

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Voice coders: quality Indicative Quality (MOS) 5

G.711 (64 kb/s)

G.721 (32 kb/s)

4

G.728 G.729 (16 kb/s) (8 kb/s)

G.xxx (4 kb/s)

Minimum qual. for high cost application

Consumer quality

3 2

STG 4198 LPC (2,4 kb/s)

STG4591 HSX (2,4 kb/s) (2,4 kb/s 1.2 kb/s)

Minimum qual. For low cost application

1 1970

1980

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1990

2000

2010

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Other low rate voice coders z ITU 4 kbits/s : no selection yet between the various

proponents z DVSI : proprietary format (IMBE and AMBE: 2 to 9.6

kbits/s) mainly chosen for satellite communications systems (Inmarsat), Iridium and APCO 25 z Texas MELP : basis for the STG 4591 Stanag z Except for ITU 4kbits/s, all have rather high processing

delay implying long PTT return time

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Amateur Radio Demonstrator z Adaptation of the DRM reference receiver for 3 kHz channels z Push-to-talk z Various modes according to : Î Voice coder rate : 1200, 2400, 3200 bits/s (4000-4800 pending) Î Modem robustness Î Choice will be made during lab and fields experiments z 100% PC based for simple integration z Full demonstrator working with Ten-Tec and Kenwood off-

the-self transceivers z Across the Atlantic tests planned for 2002 with ARRL THALES COMMUNICATIONS

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MMI in transmit mode

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MMI in receive mode

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CONCLUSIONS z DRM World-wide standard is a good technology basis

for Ham z Narrow band, PTT mode easily derived for HF Ham use z Available low bit rate vocoder quality reached acceptable

quality z ARRL plans lab tests then trans-atlantic tests in 2002

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Thank you for your attention

Questions ??

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TECHNOLOGIES RADIO & SIGNAL UNIT Australia: China: Canada: Czech R. Croatia Egypt: Ecuador: France: Finland: Germany: Hungary: India: Italy: Japan: Luxembourg Malaysia: Netherlands: Nigeria: Norway: New Zealand: Russia: Spain: Sweden: Switzerland: Tunesia: UK: USA:

FARB Academy of Broadcasting Science Radio Canada International, Nautel Ltd HFCC RIZ Egyptian Radio and Television Union ESPOL, HCJB Atmel, CCETT, Europe 1, Radio France, Radio France Int., TDF, Thales Kymenlaakso Polytechnic 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 Communication Authority, Antenna Hungaria All India Radio RAI Hitachi Kokusai, JVC, NHK Broadcasting Centre Europe (RTL-CTL) ABU Nozema, Radio Nederland Wereldomroep Voice Of Nigeria Telenor Radio NZ Int. Main Centre for Control of Broadcasting Networks and the Voice of Russia Retevision, Universidad del Pais Vasco Coding Technologies, Radio Sweden Int., TERACOM SE, Factum Electronics AB EBU, ITU, ICRC Arab State Broadcasting Union BBC, Christian Vision, LSI Logic, Merlin Com. Int., Qinetiq Ltd, Roke Manor Research Ltd., RadioScape Continental Electronics Corp., Harris Corp., Sangean America, TCI, IBB/VOA, NASB

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DIAM Chipset RF Analogue Front-End

RF Digital Front-End FM input

Switch Matrix DDC2

AM input DDC1

ANALOG CHIP

APB bus

Audio output Host processor

Audio interface

Initial Synchro

Symbols Demodulation

MLC decoder: Viterbi decoding processor (HW)

D-Cache 8 kbytes

USB (or other) interface

Ext. data mem. 4 Mbit SRAM

I-Cache 8 kbytes

MLC decoder: control part (SW) Demux

I-TCM

32 kbytes

D-TCM

64 kbytes

Audio decoders

MMI and data services

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Ext. prog. mem. 2 Mbit Flash DMA

APB bridge

AHB

Internal controls and configurations

Ext. data mem. 8 Mbit SRAM

Narrow-band jammer rejection

Ext. prog. mem. 2 Mbit Flash

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Demonstrator Description Î Can transmit at the same time vocoded voice + data

(text message, text files, image files...) Î available HSX vocoders : 1200 b/s, 2400 b/s, 3200 b/s (easy addition of other vocoders) Î Can receive both DRM and SSB Ê SSB : audio ouput is the SSB audio Ê DRM : audio output is the vocoder output. In this case, also displays frame error rate, frequency offset, estimated SNR, estimated channel impulse response (in 3D representation)

Î 3 degrees of protection : Ê GND (Ground-wave) for short distance communication Ê SKY (Sky Wave) for long distance Ê ROB (Robust) for difficult conditions

Î Choice between short and long interleaving

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Demonstrator Main Features z A simple hardware interfacing system with Radio-Amateur

transceivers Î levels adaptations Î Push-To-Talk detection Î an adjustable VOX system Î receiving level monitoring (if available)

z Easy personalisation Î one editable text file defines the preferred starting options Î one additional editable text file (Settings.cmd) allows adjusting other parameters (thresholds, gains, squelch level...)

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Other features z Automatic re-programming of the receiver according to the z z z z z z

currently received message Integrated auto-test Sophisticated channel simulator (for checking performances in terms of SNR, frequency offset, channel severity) PTT test Monitoring level test Transmission of a pure tone instead of the DRM signal Local vocoder auto-test

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