Digital Multimedia Broadcasting
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2008-07-11T04:07:05Z
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{{otheruses|DMB}}
{{Table Digital video broadcast standards}}
'''Digital Multimedia Broadcasting''' ('''DMB''') is a [[digital]] [[radio transmission]] system for sending [[multimedia]] ([[radio]], [[TV]], and [[datacasting]]) to [[mobile device]]s such as [[mobile phone]]s. This technology, sometimes known as "[[mobile TV]]", is an offshoot of [[Digital Audio Broadcasting]] which was originally developed as a research project for the [[European Union]] (Eureka project number EU147). DMB was developed in [[South Korea]] under the national IT project, originally as the next generation digital technology to replace the FM radio.<ref>[http://ericemoon.googlepages.com/IntroductionofDMBinKorea.pdf The Introduction of DMB in Korea]</ref> The world's first official mobile TV service started in South Korea in May 2005, although trials were available much earlier. It can operate via [[communications satellite|satellite]] ([[S-DMB]]) or terrestrial ([[T-DMB]]) transmission. DMB is based on the [[Eureka 147]] [[Digital Audio Broadcasting]] (DAB) standard, and has some similarities with the main competing [[mobile TV]] standard, [[DVB-H]]. <ref>[http://eng.t-dmb.org/ T-DMB]</ref>
Like DAB, T-DMB is made for transmissions on [[radio frequency]] [[band (radio)|band]]s band III ([[VHF]]) and [[L band|L]] ([[Ultra high frequency|UHF]]), for terrestrial. Because the [[United States]] and [[Canada]] still [[frequency allocation|allocate]] the first band for television broadcasting (VHF channels 7 to 13) and the United States reserves the L band for military applications, DMB is still unavailable in North America. [[Qualcomm]]'s [[MediaFLO]] is a [[proprietary]] system used there instead. In [[Japan]], [[1seg]] is the standard, using [[ISDB]].
T-DMB uses [[MPEG-4 Part 10]] ([[H.264]]) for the video and [[MPEG-4 Part 3]] BSAC or [[HE-AAC]] V2 for the audio. The audio and video is encapsulated in [[MPEG transport stream|MPEG-2 TS]]. The stream is RS encoding and the parity word is 16 bytes length. There is [[convolution]]al [[interleaving]] made on this stream, then the stream is broadcast in data stream mode on [[Digital audio broadcasting|DAB]]. In order to diminish the channel effects such as fading and shadowing, DMB modem uses [[OFDM]]-[[DQPSK]] modulation. A single-[[computer chip|chip]] T-DMB receiver is also provided by an [[MPEG-2]] [[transport stream]] [[demultiplexer]].
DMB has several applicable devices such as mobile phone, portable TV, PDA and [[telematics]] devices for [[automobile]]s.
T-DMB is an [[ETSI]] standard (TS 102 427 and TS 102 428). As of December 14, 2007, [[ITU]] formally approved T-DMB as the global standard, along with three other standards,like DVB-H, OneSeg, and MediaFLO.<ref>[http://www.koreatimes.co.kr/www/news/biz/2007/12/123_15630.html] ITU approves Mobile TV Standards]</ref>
==Deployment==
Currently, DMB is being put into use in a number of countries, although mainly used in South Korea.
===South Korea===
In [[2005]], [[South Korea]] started S-DMB and T-DMB service on [[May 1]] and [[December 1]], respectively. [http://www.asiamedia.ucla.edu/article.asp?parentid=23866] [http://www.asiamedia.ucla.edu/article.asp?parentid=34172]
[[As of 2006|As of December 2006]], T-DMB service in South Korea consists of, 7 TV channels, 12 radio channels, and 8 data channels. These are broadcast on six [[multiplexing|multiplex]]es in the VHF band on TV channels 8 and 12 (6MHz faster).
As of April 2007, S-DMB service in South Korea consists of 15 TV channels and 19 radio channels and 3 data channels.
S-DMB service in South Korea is provided on a [[subscription]] basis through [[TU Media]] and is accessible throughout the country. T-DMB service is provided free of charge, but access is limited in selected regions.
Around one million receivers have been sold [[As of 2006|as of June 2006]]. Receivers are integrated in car [[navigation system]]s, [[mobile phone]]s, [[portable media player]]s, [[laptop computer]]s and [[digital camera]]s.
South Korea has had Full T-DMB services including JSS ([[Jpeg Slide Show]]), DLS ([[Dynamic Label Segment]]), [[BWS]], and [[TPEG]] since 2006.
In Mid August 2007, [[Iriver]], a multimedia and micro-technology company released their "NV", which utilizes South Korea's DMB service.
In October 2007, South Korea added broadcasting channels MBC, NET and ADD to the DMB channel. There are now eight DMB video channels in Seoul and six in other metropolitan cities.
===DMB in automobiles===
T-DMB works flawlessly in vehicles traveling up to 120km/h. In tunnels or underground areas, both TV and Radio broadcast is still available, though DMB may skip occasionally. Fortunately, the broadcast recovers quickly.
===Europe and some other countries===
Some T-DMB [[evaluation|trial]]s are currently planned or available around [[Europe]] and other countries:
* [[Germany]]'s 'Mobiles Fernsehen Deutschland' (MFD) launched the commercial T-DMB service "Watcha" in June 2006, in time for the [[2006 FIFA World Cup|World Cup 2006]], marketed together with [[Samsung Electronics|Samsung]]'s P900 DMB Phone, the first DMB Phone in Europe. It was stopped in April 2008 as MFD is now favouring DVB-H, the European standard<ref>Broadband TV news: [http://www.broadbandtvnews.com/?p=4682 MFD hands back German T-DMB licence], May 1, 2008</ref>.
* [[France]] is currently running a trial in [[Paris]].
* [[Indonesia]] is currently running a trial in [[Jakarta]].
* [[NRK]] is currently running a trial in [[Trondheim]], [[Norway]].
* [[Italy]] ran a 6-month trial in some areas, they decided to cover more than 50% of the population before the end of 2007.
* [[China]] is planning to do DMB service during the 2008 Olympics.
* [[Ghana]] is currently running a trial in Accra on Onetouch mobile network.
==See also==
* [[1seg]]
* [[China Multimedia Mobile Broadcasting]] ([[CMMB]])
* [[Digital Audio Broadcasting]] (DAB)
* [[Digital Radio Mondiale]] (DRM)
* [[Digital Video Broadcasting]] (DVB)
* [[DVB-H]]
* [[ETSI Satellite Digital Radio]] (SDR)
* [[FMeXtra]]
* [[Handheld projector]]
* [[Internet radio device]]
* [[Multimedia Broadcast Multicast Service]]
* [[Satellite radio]]
* [[Satellite television]]
* [[WiBro]]
* [[WiMAX]]
* [[WorldDMB]]
==References==
<references/>
==External links==
===Official===
*[http://www.worlddab.org/ WorldDMB]
*[http://eng.t-dmb.org/ t-dmb.org]
*[http://eng.t-dmb.org/ T-DMB Official site of S. Korea ]
*[[ETSI]] T-DMB Specifications available at [http://pda.etsi.org/pda/queryform.asp ETSI Publications Download Area] (this will open ETSI document search engine, to find the latest version of the document enter a search string; free registration is required to download PDF)
**[http://pda.etsi.org/pda/home.asp?wki_id=D4@Y,sq,hunpppprz8wSh TS 102 427]
**[http://pda.etsi.org/pda/home.asp?wki_id=jJQf3MzQ2sSUUUUVdR6W6 TS 102 428]
=== Other ===
Related websites
* [http://www.digitalradiotech.co.uk News and information on the new digital broadcasting systems]
* [http://www.TheCatalyst.nl/ The Catalyst: e-zine on DAB in the Netherlands]
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[[Category:Digital radio]]
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[[fr:Diffusion Multimédia Numérique Terrestre]]
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