On 16 June 2006, a treaty agreement was signed at the ITU Regional Radiocommunication Conference (RRC-06) in Geneva, setting a target date of 17 June 2015 for the digitalization of broadcasting in Europe, Africa, Middle East and Central Asia (known as Region 1 in ITU).
The change from analogue to digital television broadcasting brings opportunities and challenges for all stakeholders, from manufacturers to broadcasters and end-users. The decision not only brings possibilities for structured development of digital terrestrial broadcasting but also sufficient flexibilities for adaptation to the changing telecommunication environment. As such, it represents a major milestone in the effort to connect underserved and remote communities and close the digital divide.
A former Chair of the World Broadcasting Unions Technical Committee, and Chair of ITU-R Working Party 6C and several groups of the DVB Project, David Wood is an expert in the field of digital broadcasting. ITU asked him about the switch from analogue to digital television broadcasting and what impact this process will have on the future of television.
The term ‘digital broadcasting’ is a catch-all term for the use of electrical signals for broadcasting that are a sequence of ‘discrete numbers’. Analogue broadcasting uses electrical signals that vary in a ‘continuous way’. The shift from analogue to digital is an inevitable one that has taken place in virtually all electronic systems over the past decades. Digital signals are much more flexible, can be squeezed into smaller spaces, and open up many more opportunities than analogue signals. The case for making the transition is as self-evident and beneficial as was changing transport from horses to motor cars. The change could bring a great deal more channels for viewers, the option of higher quality images, multimedia, and more involving and inclusive television.
The technology for digital television was developed in the nineties, but this is not all you need to introduce digital television. You need a ‘radio frequency spectrum’ plan, which is like a giant jigsaw puzzle. You have to allocate the transmitter locations and coverage areas to meet each nation’s needs, and to be sure that when the digital services are on air they don’t interfere with viewers in neighbouring countries. Such a plan needs to be agreed at an international frequency planning conference, and such a conference was organized in Geneva in 2006. Over 1000 delegates from 104 nations took part from what is called ITU Region 1: Europe, Africa, the Middle East and Central Asia. They set a target date for completing the transition in the UHF bands – the digital switchover – for the signatory nations by 17 June 2015. This has largely been met, though there are some exceptions.
The benefit begins with a greater number of broadcast television channels being possible. In the analogue days, viewers were limited to four or five television channels. With digital broadcasting, the number of channels of the same technical quality that can be offered is multiplied by at least four. One of the benefits of digital broadcasting is that the image quality and the number of channels can be traded off. It’s also possible to provide electronic programme guides to help viewers find what they want. More recently, digital broadcasting allows the TV set to link programmes to Internet content.
We should also note that there are nations that plan to use part of what was previously the television broadcast radio spectrum for wireless Internet services in future after switchover, and for this part of the spectrum to be sold by auction, so part of the ‘digital dividend’ may also be cash for the government.
What direction digital TV can take in future may depend, among other things, on the results of an ITU conference later this year, the World Radiocommunication Conference 2015 (WRC-15). The conference will consider to what degree the radio spectrum currently allocated to television broadcasting should be used for other things after the digital switchover.
There are several schools of thought. One is that the efficiency gains of digital broadcasting should be used to develop digital broadcasting with new services such as ultra-high definition television. Such systems are being developed internationally with four times and sixteen times the image detail of high definition television. Another school of thought is that at least part of the spectrum would be better used for wireless broadband, which would bring cash for governments by the sale of spectrum, and easier access to the Internet for the public. The Internet itself could provide television programmes as a substitute for broadcasting.
Whatever the outcome, an exciting future lies ahead, made possible by the ITU conference in 2006.