DIGITAL RADIO & MULTIMDEDIA

- Shi S. R. AGGARWAL

ENGINEER-IN-CHIEF ALL INDIA RADIO

 

 

Mobile multimedia

-Mobile multimedia primarily includes video and other rich media content sent to users via wireless networks and hase evolved significantly over the past 5 years.

-Mobile Multimedia could be one way or interactive.

 

Interrnet Protocol Television(IPTV)

>It is defined  as multimedia service  such as television/video/audio/text/graphics/data delivered over IP based networks managed to provide the required level of quality of service and experience, security, interactivity and reliability.

> IPTV is sensitive to packet loss and delays if the streamed data is unreliable.

> Limited  connection speed/bandwidth available is also a bottleneck for large IPTV customer base.

 

3G?    

> 3G or 3rd Generation, is a family of standards for a wireless communication  defined by the ITU, which includes GSM, EDGE, UMTS and CDMA 2000 as well as DECT and WiMax.

>3G allows simultaneous use of speech and data service  and higher data rates typically 14Mbits.

 

Radio Broadcasting

> AM

-    Audio Quality not very good

-   No scope for Data Broadcasting

-   Limited fidelity of existing AM services 

-   Listeners  always search for better 

       alternatives.

> FM

-  Good Audio Quality

-  Scope for Data Broadcasting

 

Why is Digital Radio Needed?

           

There is a global trend towards the adoption of digital technology in radio and communications, especially for distribution and transmission.

Digitalisation offers many substantial advantages to national / international broadcasters and info casters.

tDRM : The System

Digital Radio Mondiale (DRM) is the universal, openly standardised, digital radio system for short-wave, medium-wave and long-wave - digital radio for the radio frequencies below 30MHz.

> It has been endorsed by the ITU, and is standardised as ETSI ES 201 980.

> Designed as a flexible system able to overcome adverse propagation conditions – deep and long fades, echoes and multipath.

> Has a variety of audio and channel coding options and modulation schemes to cope  with different channel bandwidth requirements?  

> DRM has near-FM sound quality

> The ease-of-use  comes from digital transmissions.

> The improvement over AM is immediately noticeable.

> DRM can be used for a range of audio content, and has the capacity to integrate text and data. This additional content can be displayed on DRM receivers to enhance the listening experience.

 

What DRM offers

 

> More choice for listeners

 - up to 4 programs on 1 frequency   simulcast analog / digital.

> Simple to use receivers.

> Excellent audio quality (MPEG-4AAC) no distortion  stereo and 5.1 surround sound.

> Added features

 -  Text  based information serviceText Messages ( programme accompanying labels), EPG,  images, slideshow, traffic info, broadcast   website.

> Automatic tuning

-  By station name, no longer by frequency   re-tunes when leaving coverage area.

> Good coverage area and robust signal

    supporting SFN (single frequency networks).

 

 Why DRM ?

> It can be used for a range of audio content, and has the capacity to integrate text and data.

> This additional content can be displayed on DRM receivers to enhance the listening experience.

 

DRM : Technical Aspects

> DRM uses the existing AM broadcast frequency bands.

> Designed to fit in with the existing AM broadcast band plan, based on signals of 9 kHz or 10 kHz bandwidth.

> It also has modes requiring only 4.5 kHz or 5 kHz bandwidth, and modes that can take advantage of wider bandwidths - 18 kHz or 20 kHz - allowing DRM to operate alongside AM transmissions in every market of the world.uses COFDM (Coded Orthogonal Frequency Division Multiplex). This means that all the data, produced from the digitally encoded audio and associated data signals, is shared out for transmission across a large number of closely spaced carriers. All of these carriers are contained within the allotted transmission channel.

> Time interleaving is applied in order to mitigate  fading. Parameters of the OFDM and coding can be varied to allow DRM to operate successfully in many different propagation environments - the selection  of the  parameters allows transmissions to be planned that find the best combination of transmitter  power, robustness and data capacity.?          The DRM system uses MPEG 4, AAC  for mixed programming providing high quality at low data rates. In addition, CELP and HVXC codings  are available to provide speech-only programming at even lower data rates.

 

MULTIMEDIA IN DRM

 

DRM  enables transmission of main programme in good audio quality and in parallel  Programme associated or non-programme associated data which can be text,  graphics, pictures or HTML-

Option IMain-Programme 24 kbps Simple text displayed.

Option 2 Music programme 20 kbps Stereo

Plus information programme in parallel speech only 4 kbps could be important news.

Option 3 Main-Programme 24 kbps Stereo 

Text, Graphic, Picture, HTML 800 bps

Option 4   Speech channel A 4 kbps

Speech channel B 4 kbps

Speech channel C 4 kbps

Music 16 kbps Stereo

Speech channel A 4 kbps

Speech channel B 4 kbps

Speech channel C 4 kbps

Regarding Multimedia in DRM

The above options are explained below-

 

The main advantage of the DRM-system is the FM-like audio quality which allows for new

programme types. Four possibilities exist as mentioned below ( more are possible):

1. Main programme in 24 KBPS along with text , i.e., usage of all available bits for the highest audio

quality which is possible and send textual information associated to the programme. In general it

should be possible to achieve 15 kHz audio bandwidth in stereo.

2. Main programme in 20 KBPS and in parallel a speech channel of fairly good quality, i.e., usage of

one rf-channel for two different programmes to be used by choice of the listener: Music in stereo

with slightly reduced audio quality( 20 KBPS) and in parallel a speech only channel (4 KBPS) with

information.

3. Main programme in 24 KBPS (good audio quality) and in parallel “programme associated or non

programme associated data, which could be text, graphics, pictures or HTLM at a low bit rate of

about 0.8 KBPS. The DRM-receiver with a display will give best results.

4. Usage of one rf-channel alternatively for three speech-only programmes at 4 KBPS followed by a

music programme in stereo at 24 KBPS. The three different speech channels have to be synchronised.

In all cases there will be savings because of the lower power consumption of a DRM-transmitter

compared to analogue transmissions. In options 2, 3 & 4, additional savings will be achieved

because of one rf-channel only for two or three different programmes

DRM+

Digital Radio Mondiale+

DRM with the additional “+”

is the extension of DRM to all

broadcasting bands up to 174 MHz

DRM Consortium decided to extend the DRM system under the project name DRM+ to operate in all the broadcasting bands up to 174 MHz. This range includes:

>  TV band (47 MHz to 68 MHz).

> OIRT FM band (65.8 MHz to 74 MHz) .

> Japanese FM band (76 MHz to 90 MHz)

> International FM band (87.5 MHz to 107.9 MHz).?      DRM+ has a narrow bandwidth and is designed to fit in the FM broadcast band plan and a frequency grid of 100 kHz.

> Its small spectrum supports its use in crowded bands. The high commonality with the existing DRM standard allows easy and fast equipment implementation.

allows easy and fast equipment implementation.

>DRM+ provides bit rates from 35 kbps to 185 kbps and, like DRM, permits up to four services. It is therefore a flexible solution allowing single or small numbers of audio services to be broadcast together. Before standardisation as a revision to the existing DRM System specification, ETSI ES 201 980, the Consortium’s members will test and verify the design with both laboratory and field based tests. 

DRM Radios & Equipment

 

> Consumer Receivers:

  - TechniSat  MultyRadio MultyRadio supports analogue reception technology (FM/MW/LW/SW) tuners and combines this with their digital successor standards DAB (Digital Audio Broadcast) and DRM (Digital Radio Mondiale).

-Himalaya DRM 2009 DRM2009 supports DAB/DRM/AM/FM services with MP3/WAV playback.       .Morphy

-MorphyRichards Morphy Richards supports DAB/DRM/AM/ FM services wiht MP3 playback via SD-card.

- Mayah Communications The DRM Receiver 2010Car/Truck Converters:

-   Coding Technologies The world’s first DRM capable USB port receiver is Coding Technologies’ Digital World Traveller

PC-based Receivers and Software

   > Coding Technologies The world’s first DRM-capable USB port receiver is Coding Technologies’ Digital World Traveller solutions for internal professional shortwave PC-card version and external professional shortwave version with USB link

 

>  DRM Receivers

 

Ø         The most important  issue is to make  available DRM receivers at  affordable cost to the vast masses.

 

Ø         It is expected that  receiver manufacturers in India and abroad  shall  address  this issue as DRM is progressively implemented in the next five years.

 

DRM Initiatives -  India

India‘s DRM Decision

 • First DRM trials in India were carried out  in

Delhi in 2007 by AIR & ABU

  Broadcasting  AM analog and DRM as simulcast on one frequency   (20 kHz channel)

 • Re-using existing transmitter infrastructure

 

 Regular AIR DRM service

 

 -  From Khampur (Delhi) started 16th Jan

2009 (250 kilowatt shortwave transmitter)

 • Approximately 5 hours towards listeners in the

UK and Europ between 2315 to 0400 IST on 9950

kHz

  • Additional three hours of local transmission within

Indi from 1430 to 1730 IST on 6100 kHz.

 

Grand Plan For Digitalization Of All  India  Radio

> There are plans to introduce DRM transmissions in 41 new medium wave DRM transmitters in replacement scheme.

> 36 existing medium wave transmitters shall be converted for DRM operation.

> 5 new shortwave transmitters shall be installed in replacement scheme.

 

INSTALLATION OF NEW 100 KW MEDIUM WAVE DRM TRANSMITTERS -11

 

INSTALLATION OF NEW 200 KW MEDIUM WAVE DRM TRANSMITTERS-10

           

INSTALLATION OF NEW 300 KW MEDIUM WAVE DRM TRANSMITTERS-6

 

INSTALLATION OF NEW 20 KW & 50 KW  MEDIUM WAVE DRM TRANSMITTERS

     -20 KW TRANSMITTERS:-6

 

      - 50 KW TRANSMITTER :-1

INSTALLATION OF NEW 10 KW MEDIUM WAVE DRM TRANSMITTERS-6

CONVERSION OF  36 ANALOGUE TRANSMITTERS  FOR  DRM OPERATION

    -300 KW MW TRANSMITTER: 5

    - 200 KW MW TRANSMITTER: 3

    - 100 KW MW TRANSMITTER: 7

     - 20 KW MW TRANSMITTER: 21

 

Looking Ahead

 There are going to be a number of wireless multimedia services coming to market over the next 3-5 years. They will all provide exciting new video, music and datacasting services that will allow subscribers to enjoy multimedia content beyond anything currently available in a wireless handset.