Digital Dividend

The introduction of digital terrestrial broadcasting, which is underway in many parts of the world, provides many benefits, among which is the professed ‘digital dividend’. Digital compression technology and coding systems allow for several television programme channels to be carried within the same bandwidth that is used by an analogue television channel. Digital terrestrial television (DTT) delivers an increasing number of quality television programmes within the same amount of spectrum that is used by an analogue channel and uses spectrum more efficiently.

So as television broadcasting migrates from analogue to digital, it is clear that all existing analogue television channels can be accommodated in less spectrum than used previously and many additional television channels can be introduced in the available broadcasting spectrum. One might say that some spectrum may be released after the analogue TV services have closed down. This release of spectrum is referred to as the ‘digital dividend’. This released spectrum could be used for many purposes, such as:

• providing many more digital television broadcasting services
  of conventional quality and resolution;
   

• providing a new service concept (partially or totally) that allows for indoor, portable and mobile reception including digital TV services for reception on hand-held receivers;
   

• providing enhanced sound and picture quality, like High Definition TV, Three-Dimensional TV;
   

• providing non-broadcasting services, like IMT, WiMAX, Wifi, etc.

It is anticipated that this 'digital dividend' is likely be used by the Member States for various purposes reflecting their political, social, and cultural considerations. Already, the digital dividend has resulted in the availability of some of the broadcasting spectrum in the UHF band in Region 1 - specifically from 790- 862 MHz, for mobile broadcasting on a primary basis from 17 June 2015. Furthermore, Agenda item 1.17 of the 2012 World Radiocommunication Conference (WRC-12) tasks the ITU-R Sector to consider results of sharing studies between the mobile service and other services in the band 790-862 MHz in Regions 1 and 3, in accordance with Resolution 749 (WRC-07) - to ensure the adequate protection of services to which this frequency band is allocated, and to take appropriate action to assure this.

ITU-R Joint Task Group 5-6 (JTG 5-6) - 'Studies on the use of the band 790-862 MHz by mobile applications and by other services' was established by the first session of the Conference Preparatory Meeting (CPM 11-1) in order to carry out these studies and to develop the text for the 'Draft CPM Report on Agenda item 1.17 (WRC-12)'. The JTG 5-6 completed its work at the meeting held from 30 April – 7 May 2010.


White spaces

Another aspect of the switch-over to digital terrestrial television broadcasting is the thorough review of the UHF broadcasting spectrum that is taking place in Administrations undertaking this transition. The terrestrial TV networks in the UHF bands have been traditionally planned as Multi-Frequency Networks (MFNs), in order to support regional TV planning and to facilitate international frequency coordination. In this type of planning, there are locations within a country where particular UHF channels are not used in order to avoid interference to TV services in adjacent regions. These channels are known as UHF white space and have been used by the broadcasters for low-power applications like radio microphones and wireless in-ear monitors, known as Programme Making and Special Events (PMSE) applications. This sharing of the broadcasting spectrum is the subject of many ITU-R Recommendations (ITU-R BT.1368 - 'Planning criteria for digital terrestrial television services in the VHF/UHF bands' and ITU-R BS.1786 - 'Criterion to assess the impact of interference to the terrestrial broadcasting service (BS)', etc.) which provide the necessary criteria for the interference-free operation of such equipment.