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Digital terrestrial television
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Digital Terrestrial Television (DTTV or DTT) is an implementation of digital technology to provide a greater number of channels and/or better quality of picture and sound using aerial broadcasts to a conventional antenna (or aerial) instead of a satellite dish or cable connection.
The technology used is ATSC in North America and South Korea, ISDB-T in Japan and Brazil, DVB-T in Europe, Australia, New Zealand, Colombia, Uruguay and some countries of Africa, and DMB-T/H in China (including Hong Kong); the rest of the world remaining mostly undecided.
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Encyclopedia
Digital Terrestrial Television (DTTV or DTT) is an implementation of digital technology to provide a greater number of channels and/or better quality of picture and sound using aerial broadcasts to a conventional antenna (or aerial) instead of a satellite dish or cable connection.
The technology used is ATSC in North America and South Korea, ISDB-T in Japan and Brazil, DVB-T in Europe, Australia, New Zealand, Colombia, Uruguay and some countries of Africa, and DMB-T/H in China (including Hong Kong); the rest of the world remaining mostly undecided. ISDB-T is very similar to DVB-T and can share front-end receiver and demodulator components.
Transmission
DTTV is transmitted on radio frequencies through the airwaves that are similar to standard analog television, with the primary difference being the use of multiplex transmitters to allow reception of multiple channels on a single frequency range (such as a UHF or VHF channel).
The amount of data that can be transmitted (and therefore the number of channels) is directly affected by the modulation method of the channel. The modulation method in DVB-T is COFDM with either 64 or 16 state Quadrature Amplitude Modulation (QAM). In general a 64QAM channel is capable of transmitting a greater bitrate, but is more susceptible to interference. 16 and 64QAM constellations can be combined in a single multiplex, providing a controllable degradation for more important programme streams. This is called hierarchical modulation.
New developments in compression have resulted in the MPEG-4/AVC standard which will enable two high definition services to be coded into a 24 Mbit/s European terrestrial transmission channel.
The DVB-T standard is not used for terrestrial digital television in North America. Instead, the ATSC standard calls for 8VSB modulation, which has similar characteristics to the vestigial sideband modulation used for analogue television. This provides considerably more immunity to interference, but is not immune - as DVB-T is - to multipath distortion and also does not provide for single-frequency network operation (which is in any case not relevant in the United States).
Both systems use the MPEG-2 transport stream and video codec; they differ significantly in how related services (such as multichannel audio, captions, and program guides) are encoded.
Advantages and disadvantages
Advantages:
- Digital reception tends to be better overall, particularly with a good signal. With a weaker signal there is little perceptible difference, in fact analogue can be better.
- It is easier to obtain the optimum digital picture than the optimum analogue picture.
- Many more channels can fit on the digital transmission.
- Interactive (red button) services can be provided.
Disadvantages:
- New equipment (set top box) may be required.
- Increased electricity consumption by the digital receiving equipment.
- An upgraded antenna installation may be required.
- Analog requires lower signal strength to get a watchable picture. By extension, digital does not degrade as gracefully as analog.
- Switching channels is slower because of the time delays in decoding digital signals.
Reception
DTTV is received via a digital set-top box, or integrated receiving device, that decodes the signal received via a standard aerial antenna. However, due to frequency planning issues, an aerial with a different group (usually a wideband) may be required if the DTTV multiplexes lie outside the bandwidth of the originally installed aerial. This is quite common in the UK, see external links.
DTT Around the world
Europe
The United Kingdom (1998), Sweden (1999) and Spain (2000) were the first to launch DTT with platforms heavily reliant on pay television. All platforms experienced many starter problems, in particular the British and Spanish platforms which failed financially. Nevertheless, Boxer, the Swedish pay platform which started in October 1999, proved to be very successful.
DTT in the United Kingdom was launched in November 1998 as a primarily subscription service branded as ONdigital, a joint venture between Granada Television and Carlton Communications, with only a few channels being available free to air. ONdigital soon ran into financial difficulties with subscriber numbers below expectations, and in order to attempt to reverse their fortunes, it was decided that the ITV and ONdigital brands should align, and the service was rebranded ITV Digital in 2001. Despite an expensive advertising campaign, ITV Digital struggled to attract sufficient new subscribers and in 2002 closed the service. After commercial failure of the Pay TV proposition it was relaunched as the free-to-air Freeview platform in 2002. Top Up TV, a lite pay DTT service, became available in 2004.
In the Republic of Ireland it'sTV was the sole applicant for a digital terrestrial television license under the provisions of the Irish Broadcasting Act 2001 which also established Telífís na Gaeilge, now TG4. It proposed a triple play deployment with Broadband, TV and Digital Radio services. However, following financial difficulties with other DTT deployments, most particularly in the neighbouring UK and in Spain and Portugal, it'sTV failed to get its license conditions varied or to get a time extension to securing funding and its license was eventually withdrawn for non performance.
Under subsequent legislation in May 2007, RTÉ and the spectrum regulator (ComReg)and the broadcasting regulator BCI (soon BAI) were mandated to invite applications during 2008 under the Broadcasting (Amendment) Act 2007. The Commission for Communications Regulation (ComReg) have issued to the BCI and RTÉ DTT spectrum licenses in December 2007 and the BCI advertised and invited multiplex submissions by May 2, 2008. RTÉ Networks is required to broadcast in digital terrestrial TV (aerial TV) under the new Act and will received an automatic license through the RTÉ Authority (soon the Broadcasting Authority of Ireland in its place) and will upgrade part of its network over a 5 year period.It will also make this network available to the commercial multiplex winner for rental of capacity. 1 Mux (group of channel radio wave space) will be provide the services of the public service broadcaster have a 98% population coverage. The other three multiplexes will have a 90% population coverage. Following ASO 1 addition PSB mux and 1 or more commercial muxes will be made available for DTT, mobile television and other services.
The BCI (soon BAI) received 3 conditional applications to operate the 3 muxes which were presented in public on May 12, 2008. It decided in principle to allocate the license to Boxer DTT Ltd, a consortium made up of the Swedish pay-DTT operator Boxer and the media group Communicorp at its board meeting on July 21, 2008. Subject to successful conclusion and clarifications in the coming months, Boxer DTT Ltd will get the license.
A Houses of the Oireachtas Channel Oireachtas TV (reportedly shelved in December 2008) and Irish Film Channel (still planned to proceed to launch) Commissions will also be established under the Broadcasting Act 2008 as new public service broadcasters. The Broadcasting Authority of Ireland will replace the Broadcasting Complaints Commission, the Broadcasting Commission of Ireland and the RTÉ Authority and include Awards and Advisory Committees. .
Boxer DTT Ireland, tentative start date is January in 2009 in Ireland . Standards chosen are MPEG4/H.264 and DVB-T. Boxer TV Access has a 50% holding in Boxer Ireland.However is is expected that this start date will be deferred to September 2009 to facilitate joint co-ordinated DTT Free-to-air and commercial DTT launches.. A DTT Information Campaign has been announced by the Department of Communications, Energy & Natural Resources Irish Government Department to launch in March 2009 ahead of the September 2009 launch of Irish DTT.
Portugal is expected to launch its DTT service in 2009 also with the public service broadcaster RTP providing FTA services in partnership with commercial broadcasters. Anacom regulates this area. One multiplex will provide free-to-air services, while 5 further multiplexes will be allocated to a single operator for the provision of free-to-air and pay-DTT services. Two candidates, Airplus TV and Portugal Telecom, have both tendered for this DTT license.
In Spain most multiplexes closed after the failure of Quiero TV, the country's original pay DTT platform. DTT was relaunched on 30 November 2005, with 20 free-to-air national TV services as well as numerous regional and local services. Nearly 11 million DTT receivers had been sold as of July 2008.
In Sweden, DTT was launched in 1999 solely as a paid service. Today (2007) there are 38 channels in 5 MUXs. 11 of those are free-to-air channels from a number of different broadcasters. Switch-off of the analogue TV service started in September 2005 and finished on 15 October 2007.
Finland launched DTT in 2001, and terminated analogue transmissions nationwide on 1 September 2007. Finland has successfully launched a mixture of pay and free-to-air DTT services. Digita operates the DTT and Mobile Terrestrial networks and rents capacity to broadcasters on its network on a neutral market basis. Digita is owned by TDF (France). ,
Germany launched a free-to-air platform region-by-region, starting in Berlin in November 2002. The analogue broadcasts are planned to cease soon after digital transmissions are started. Berlin became completely digital on 4 August 2003.
France's TNT (Télévision Numérique Terrestre) offers 18 free and 11 pay channels. An 89% DTT penetration rate is expected by December 2008. Free-to-view satellite services offering the same DTT offer were made available in June 2007. FTA TNT uses MPEG2 while pay TNT in 2008 uses the MPEG4 AVC/H.264 compression format.
Bulgaria launched a free-to-air platform on Sofia region, starting in November 2004. Standards chosen are DVB-T/DVB-T2 and MPEG4/H.264 compression format.
Luxembourg launched DTT services in April 2006. The national service launched in June 2006. On 1 September 2006, Luxembourg became the first European country to transition completely to DTT.
The EU recommended in December 2005 that its Member States cease all analogue television transmissions by the year 2012. Some EU member states decided to complete the transition as early as 2007 (e.g. Finland), nevertheless two member states (unspecified in the announcement) have expressed concerns that they would not be able to switch due to technical limitations.
North and South America
In the United States by no later than June 12, 2009, all full power U.S. television broadcasts will be exclusively digital, under the Digital Television and Public Safety Act of 2005. Furthermore, starting March 1, 2007, new television sets that receive signals over-the-air, including pocket sized portable televisions, must include ATSC digital tuners for digital broadcasts. Currently, most U.S. broadcasters are transmitting in both analog and digital formats; a few are digital-only. Most U.S. stations are not permitted to shut down their analog transmissions prior to February 16, 2009, unless doing so is required in order to complete work on a station's permanent digital facilities. In 2009, the FCC will finish auctioning channels 52–59 (the lower half of the 700 MHz band) for other communications services, completing the reallocation of broadcast channels 52–69 that began in the late 1990s.
The analog switch-off will render all non-digital televisions unable to receive most over-the-air television channels; however, low-power television stations and cable TV systems are not required to convert to digital until 2011 or later. Beginning January 1, 2008, consumers may request coupons to help cover most of the cost of these converters by calling a toll free number or via a website.
In Canada, analog switchoff is scheduled for August 31, 2011. Most network stations are already broadcasting high-definition digital signals in Toronto, with partial network digital coverage in Ottawa, Montreal and Vancouver. In Mexico, digital signals are on-air in the largest markets, with more cities to be added in descending order of size until full national coverage is reached in 2021; at that point analogue broadcasts will end.
In Venezuela, tests are being performed with full deployment to start 2008-2009. DTT will coexist with analog standard television for some time, until full deployment of the system on a nationwide level is accomplished.
In Brazil, they chose a modified version of the Japanese ISDB-T standard, called ISDB-Tb (or SBTVD) in June, 2006. Digital broadcast started in December 2, 2007 in São Paulo and now it is under expansion all over the country (as of January 22, 2009, only metro areas of São Paulo, Rio de Janeiro, Belo Horizonte, Goiânia, Curitiba, Porto Alegre, Salvador, Campinas and Cuiabá have digital terrestrial broadcasting). Analog shut-off is scheduled for June 29, 2016.
Cuba has announced recently that it will decide on the norm to use, within the current year. According to official sources of the MIC (Ministry of Computer science and Telecommunications) the Caribbean island is deciding between the European format DVB or the DSM format used by China. At the moment, Cuban specialists are performing tests in both formats but an "analogical blackout" is far away.
Uruguay has chosen the European DVB-T standard.
Colombia has chosen the European DVB-T standard on August 28,2008.
Ecuador is currently assessing which standard to use (2008-2009).
Asia
Japan
Japanese Ministry of Internal Affairs and Communications and Dpa (The Association for Promotion of Digital Broadcasting-Japan) jointly set the specification and announced the guide line of "simplified DTT tuner" with price under 5,000 Japanese yen on December 25, 2007. MIAC officially solicit manufactures to put it on the market by end of March 2010 (end of fiscal year 2009). MIAC is estimating 14 million, at maximum, set of traditional non-digital TV remains and needs the "simplified DTT tuner" to be adapted even after complete transition to DTT after July 2011, and is aiming to avoid disposal of large number of useless TV sets without such a tuner at one time.
December 20, 2007, Japan Electronics and Information Technology Industries Association set the rule (of copy control) for DTT broadcasting allows consumers up to 10 time of dubbing of entire TV program with video and audio into DVD recorder and etc. by naming "Dubbing 10"(:ja:????10) (actually up to 9 times of copy then 1 time or last time of move) and is supposed to start the broadcasting with "Dubbing 10" at about 4:00 a.m. on June 2, 2008, but postponed, that settled after long talks with Japanese Society for Rights of Authors, Composers and Publishers, then confirmed to start about 4:00 a.m. on July 4, 2008. The manufacture for DVD recorder and associated DTT recorder will make unit conforming "Dubbing 10" rule and some manufacture shall release the down loading subprogram to up date recorder's internal software for existing user.
April 3, 2008, Dpa (The Association for Promotion of Digital Broadcasting-Japan) announced that total 32.71 million of DTT (ISDB-T) receiving TV sets (except 1seg receiver) are installed in Japan as of end of March 2008. Dpa also announced the guide line documentation to manufacture who make the DTT receive, recod and replay unit to operate with Personal computer on April 8, 2008 . This add-on unit operates on USB or PCI BUS, and started to sell on reservation basis from late April and put on retail store in mid. May 2008.
May 8, 2008, the Ministry of Internal Affairs and Communications announced that 43.7% of homes have DTT (ISDB-T) receiving TV and/or Tuner with DVD recorder by end of March 2008, which was 27.8% in one year before, and expecting 100% by April 2011.
Analogue to digital transition
The broadcasting of digital terrestrial transmissions has led to many countries planning to phase out existing analogue broadcasts. This table shows the launches of DTT and the closing down of analogue television in several countries.
- Official launch: The official launch date of digital terrestrial television in the country, not the start for trial broadcasts.
- Start of closedown: The date for the first major closedown of analogue transmitters.
- End of closedown: The date when analogue television is definitely closed down.
- System: Transmission system, e. g. DVB-T, ATSC or ISDB-T.
- Interactive: System used for interactive services, such as MHP and MHEG-5.
- Compression: Video compression standard used. Most systems use MPEG-2, but the more efficient H.264/MPEG-4 AVC has become increasingly popular among networks launching later on. Some countries use both MPEG-2 and H.264, for example France which uses MPEG-2 for standard definition free content but MPEG-4 for HD broadcasts and pay services.
Country
| Official launch
| Start of
closedown
| End of
closedown
| System
| Interactive
| Compression
| References
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| Albania | 2004-07-15 | | 2012 | DVB-T | | MPEG-2 | | | Andorra | | | 2007-09-25 | DVB-T | MHP | MPEG-2 | | | Australia | 2001-01-01 | The new government has formed a Digital Switchover Taskforce | 2013-12-31 | DVB-T (7MHz channels 6~12 VHF
and 29~69 UHF) | MHP | MPEG-2, H.264 | | | Austria | 2006-10-26 | 2007-03-05 | | DVB-T | MHP | | | | Belgium | 2002/2003 | 2008-11-03 (Flemish Community) | 2011 (Francophone Community) | DVB-T | None | MPEG-2 | | | Brazil | 2007-12-03 | — | 2016-06-29 | ISDB-T | Ginga | H.264/MPEG-4 AVC | | | Bulgaria | 2004-11 | 2009-03 | end 2012 | DVB-T | MHP | MPEG-4 | | Canada | | | 2011-08-31 | ATSC | | MPEG-2,H.264(ATSC 2.0) | | | China | 2007-2008 | | | DMB-T/H | | MPEG-2 | | | Croatia | 2002-05-13 | 2008-09-01 | 2011-01-01 | DVB-T | | | | | Czech Republic | 2004 | 2007-08 | 2010-10 | DVB-T | MHP | MPEG-2 | | | Denmark | 2006-03-31 | 2009-11-01 | | DVB-T | MHP | MPEG-2, H.264 | | | Estonia | 2006-12-15 | 2008-03-31 (Ruhnu island) | 2010-07-01 | DVB-T | MHP planned | H.264/MPEG-4 AVC | | | Faroe Islands | 2002-12 | 2002-12 | | DVB-T | | | | | Finland | 2001-08-27 | 2007-09-01 | 2007-09-01 | DVB-T | MHP (abandoned) | MPEG-2 | | | France | 2005-03-31 | 2008-03 | 2011-11-30 | DVB-T | | MPEG-2, H.264 | | | Germany | 2002-11 | 2003-08 | 2008-11-25 | DVB-T | | MPEG-2 | | | Greece | 2006 | | | DVB-T | | | | | Hong Kong | 2007-12-31 | | 2012 | DMB-T/H | MHEG-5 (TVB) | MPEG-2, H.264 | | | Hungary | 2008-12-01 | | 2011-12-31 | DVB-T | | H.264/MPEG-4 AVC | | | Ireland | 1999-2002 attempt abandoned;
2006-2008 Technical Trial;
09-2009 public launch planned with FTA and pay DTT launch covering 75% of the country by launch-time | 2012-09-30 | 2013-TBD | DVB-T | RCT abandoned, MHEG5, | H.264/MPEG-4 AVC |
| | Israel | July 2009 | January 2011 (planned) | | DVB-T | | MPEG-4 | | | Italy | 2004-01-01 | | 2012-12-31 | DVB-T | MHP | MPEG-2, H.264 | | | Japan | 2003-12-01 | | 2011-07-24 (planned) | ISDB-T | BML | MPEG-2 | | | Lithuania | 2006 | | | DVB-T | | MPEG-4 | | | Luxembourg | 2006-04-04 | 2006-04-04 | 2006-09-01 | DVB-T | None | MPEG-2 | | | Malaysia | 2006-09 (trials) | | 2015 | DVB-T | MHEG-5 | H.264 | | | Mexico | 2004-07-05 | | 2022-01-01 | ATSC | | MPEG-2,H.264(ATSC 2.0) | | | Morocco | 2007-06-01 | | | DVB-T | | | | | Netherlands | 2003 | | 2006-12-11 | DVB-T | | | | | New Zealand | April 2008 | 75% digital penetration or 2012, whichever comes first. | 1 year after start | DVB-T | MHEG-5 | H.264/MPEG-4 AVC | | | Norway | 2007-09 | 2008-03 | 2009-12 | DVB-T | | H.264/MPEG-4 AVC | | | Philippines | 2006(trials)
2010 | 2010/2012 | 2015-12-31 | DVB-T | | MPEG-2, H.264 | | | Poland | 2004 (trials)
2009-01-01 | | 2012-12-12 | DVB-T | | H.264/MPEG-4 AVC | | | Portugal | 2009-04-29 | 2011 | 2012-04-26 | DVB-T | | H.264/MPEG-4 AVC | | | Romania | 2005-12-01 | | 2012-12-31 (planned) | DVB-T | | MPEG-4 | | | Russia | 2010 | 2015 | | DVB-T | | MPEG-4 | | | Slovenia | 2007 | 2010 | 2011 | DVB-T | | H.264/MPEG-4 AVC | | | South Africa | 2006-03 | 2008-11-01 | 2011-11-01 | DVB-T | | H.264/MPEG-4 AVC | | | South Korea | 2001 | | 2012-12-31 | ATSC | | MPEG-2,H.264(ATSC 2.0) | | | Spain | 2000-2005 | 2009 | 2010-04-03 | DVB-T | MHP | MPEG-2, H.264 | | | Sweden | 1999-04-01 | 2005-09-19 | 2007-10-15 | DVB-T | MHP | MPEG-2/H.264 | | | Switzerland | 2001 | 2002-03 | 2009-10 | DVB-T | | | | | Taiwan | 2006-07 | 2008 | 2010 | DVB-T | | MPEG-2, H.264 | | | Turkey | 2006-02 (trial services) | | | DVB-T | | | | | Ukraine | 2008 | 2012 | 2015 | DVB-T | none | MPEG-4 | | | United Kingdom | 1998-11-15 | 2007 (Whitehaven) | 2012 | DVB-T | MHEG-5 | MPEG-2, H.264 | | | United States | 1998-10-29 | 2007 | 2009-06-12 | ATSC | | MPEG-2,H.264(ATSC 2.0) | |
See also
External links
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- - including data on DTT deployments worldwide
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- Digital Broadcasting Experts Group (DiBEG)
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