Radio Spectrum

Digital Terrestrial Television (DTT)

Digital Video Broadcasting – Terrestrial (DVB-T / DVB-T2)

DTT is transmitted using the radio spectrum, as is the current analogue television system. DTT utilises digital technology to broadcast a greater number of channels with potentially better video and sound quality than current analogue transmissions. DTT is an alternative to using MMDS, cable or a satellite dish connection.
Digital Video Broadcasting – Terrestrial (DVB-T) is a European standard (EN 300 744) commonly used to transmit digital TV on terrestrial DTT networks. DVB-T is the transmission standard used in Ireland. Test transmissions of DVB-T started in 2006. International developments in 2009 have seen DVB-T2, a more robust and more efficient coding standard also becoming available (EN 302 755). There are currently no plans to use the DVB –T2 standard for DTT in Ireland.

Digital Sound Broadcasting

Digital Audio Broadcasting (DAB/DAB+)

DAB/DAB+ are digital technologies used by broadcasters to transmit sound broadcasting services such as traditional radio services in the digital era. DAB/DAB+ offer many advantages to broadcasters and listeners. The principal advantages include the following:

• It is developed with multimedia applications in mind and therefore, not only audio but also text, graphics and data can be broadcast simultaneously, enhancing the listener experience. For example, this could allow a broadcaster to include pictures/album sleeve of an artist’s discography while his/her music plays, or could allow other graphics such as a stock ‘ticker’ to be transmitted during a financial or news programme etc; and
• It is considered to be more robust to interference than the traditional analogue radio systems. Analogue radio signals such as those on the ‘FM’ band (i.e. the VHF Band II) or ‘MW’ band (i.e. the MF Band) is more susceptible to interference if the listener is on the move. Also other factors including terrain (e.g. mountains), high-rise buildings, electrical equipment and weather conditions can contribute to less than perfect reception of a radio station.

DAB is standardised by the European Telecommunications Standards Institute (ETSI) as standard ETSI 300 401. DAB utilises MPEG Audio layer II.

DAB+ was standardised as ETSI TS 102 563 “Digital Audio Broadcasting (DAB) Transport of Advanced Audio Coding (AAC) Audio”. DAB+ utilises the MPEG-4 HE-AAC v2 audio codec which is more spectrally efficient than MPEG Audio layer II.

Foundations of DAB/DAB+
A project was setup in 1985 to develop a new digital transmission system for radio, which would overcome the shortcomings of the traditional analogue radio networks (see above). As a result, DAB was first developed in the late 1980s, based on MPEG Audio Layer II coding, which was state of the art at the time. Known also as “Eureka 147” DAB gets its name from the one hundred and forty-seventh project of the European framework for technical research and development projects (Eureka). DAB+ is an addition to the Eureka 147 family of technologies (added in February 2007).

Digital Radio Mondiale, DRM (Mode A-D), DRM+ (Mode E)

Digital Radio Mondiale (DRM) is a digital broadcasting system for broadcasting in bands below 30MHz and includes DRM (Modes A-D). DRM is mooted as the digital replacement for the analogue transmissions in the ‘LW’, ‘MW’ and ‘SW’ bands.
DRM is standardised as ETSI ES 201 980 and has been adopted by the International Telecommunications Union (ITU).
There is also an extension of the DRM technologies to operate in the broadcasting bands up to 120MHz, this is known as DRM+ (also known as DRM Mode E) and is standardised as ETSI ES 201 980 V3.1.1 (2009-02-16). This technology has the potential to operate in the ‘FM’ band (i.e between the frequency range of 87.5MHz – 108.0MHz).
Technical studies are underway at an international level to determine whether digital technologies could be utilised to make more efficient use of the spectrum available (87.5MHz – 108MHz). The ‘FM’ band is limited in capacity and in some countries further ‘FM’ radio stations cannot be accommodated. Due to its greater spectrum efficiency DRM+ is a candidate system to replace analogue FM services as it can provide up to 186kbps using only 96 kHz bandwidth. Further information may be obtained on the DRM.org website. www.drm.org

HD Radio

iBiquity Digital’s proprietary HD Radio (HD Radio) technology is another technology which can offer a spectrum efficient upgrade path to Digital in the ‘FM’ band. HD Radio uses an In Band On Channel (IBOC) approach to transmit analogue and digital signals using 400kHz bandwidth. This approach facilitates a transitional process where analogue and digital transmission use the same channel; however a potential disadvantage is that the channel requires a larger bandwidth than a traditional FM broadcast. Further information may be obtained on the HD radio’s website www.hdradio.com.

Mobile TV

Digital Video Broadcast – to Handheld (DVB-H)

DVB-H is largely based on the DVB-T specification for digital terrestrial television, adding to it a number of features designed to take account of the limited battery life of small handheld devices, and the particular environments in which such receivers operate. The use of a technique called time-slicing, where bursts of data are received periodically, allows the receiver to power off when it is inactive leading to significant power savings. DVB-H also employs additional forward error correction (FEC) to further improve the already excellent mobile performance of DVB-T. See section on DTT previously.

Source www.dvb-h.org

A trial operated in Dublin in 2007 and 2008, which experimented with the use of DVB-H in providing mobile TV to 400 trial participants. Up to 13 TV channels were broadcast on a single UHF channel of 8MHz bandwidth using a single DVB-H Multiplex. These included Irish, UK and dedicated sports channels. The trial was deemed to be successful and ComReg commenced a process to provide for the authorisation of a Mobile TV service using spectrum it identified in five urban areas, further information is available on our consultations page. 

Digital Multimedia Broadcasting (DMB)

DMB is largely based on the DAB specification (see above, which makes it another member of the so called Eureka 147 family of technologies). DMB is designed to deliver video/multimedia services operating on the same technical basis as DAB. The only change is that the broadcaster needs to add a DMB video encoder to an existing DAB system. Therefore the three technologies DAB, DAB+ and DMB can be used alongside each other on one multiplex and basically use the same infrastructure. Further information on DMB, DAB and DAB+ can be obtained on the World DMB website.

Test & Trial

ComReg operates a special licensing regime to encourage innovation and development involving new radio technologies or services. Two licence types are available, one covering technology tests and the other covering service trials involving third parties or the public. For further information please see www.Testandtrial.ie