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Preparing for the Digital Dividend

Steps taken prior to 2012 towards the Digital Dividend

The ITU World Radiocommunications Conference 2007 (WRC07) decided to make part of the UHF TV band available to mobile telephony. 

In 2008 the Commission for Communications Regulation (ComReg) began discussions with their counterpart Ofcom in the UK in order to prepare a digital television plan which would fit within the reduced spectrum available for TV in the UHF band. 

ComReg are responsible for international negotiations with neighbouring countries regarding the detail of spectrum use in Ireland and for issuing Wireless Telegraphy licences. ComReg undertook a number of consultations (ComReg 10/59) regarding this work.

The Broadcasting Act of 2009 requires ComReg to make spectrum available for Digital Television multiplex transmissions. Digital Television services started in May 2010. RTE kept the Department informed on the Saorview network roll out process.

Terrestrial television broadcasting completed migration from the traditional analogue transmission to digital transmission in October 2012. TV services stopped using the frequencies 790-862MHz (800MHz band),  in November 2012.  This spectrum is sometimes called the first Digital Dividend,
   
ComReg manage Ireland's spectrum resource. ComReg bundled the digital dividend 800MHz band spectrum with the existing 900MHz band and 1800MHz band cellular telephony spectrum in an auction in autumn 2012. The first digital dividend enabled cellular telephony systems to be use 60MHz of the 800MHz band.

Filters may need to be fitted in some households.  

Since 2013 "Long Term Evolution (LTE)" 4G systems operate on the frequencies previously used by TV. Some viewers may have to have a filter installed at their TV or Set Top Box in order to reduce the strength of the cellular signal. Such filters improve the  compatibility (see EBU article) between LTE 4G mobile telephony systems and the Digital Terrestrial Television (DTT) system.

Viewers will most likely need to use filters where channel 58 (770MHz) or 59 (778MHz) are used by DTT. Also, due to potential so called image channel "N+9" sensitivity of some receivers, viewers may need to fit filters where their TV or set-top-box receives DTT operating above channel 51. Thus installations using the "group C/D" type aerial may need a filter. The Department wishes to advise viewers that experts expect more difficulties could arise at locations close to LTE base stations than at locations farther from the LTE base stations.  A number of suppliers offer such filters. Both  indoor filters   and outdoor filters  are available. For reception of channel 59 the filter will need to provide signal reductions above 790MHz whilst having a low loss in ch 59 (778MHz). The Broadcasting Act of 2009 requires ComReg to make spectrum available for two PSB mulitplexes and four other multiplexes. ComReg has planned that these DTT services will not use ch 60 (786MHz). ComReg have addressed this matter in Annex 9 of their document Multi-band Spectrum Release - Annexes to 12/25 (Response to Consultation and Decision on Multi-band Spectrum Release [D04/12]) (ComReg 12/25a).


Viewers should use the Saorview coverage checker to indicate whether the DTT transmissions serving an area are in channel 51 or higher.

Consumers should fit filters when they have also installed a mast head amplifiers.

Installations which use a mast head amplifier for TV reception (irrespective of the DTT frequencies) will most likely need a filter. This is because mast head amplifiers are prone to overloading. An "overload" condition can occur if the signal level from either DTT or other sources (on frequencies either above or below the TV signal) is very strong.. In these overload conditions unintended signals called "intermodulation products" can be radiated causing interference to other users of the spectrum.

Viewers should only use mast head amplifiers for reception of DTT where there is a clear need to do so. Excessive amplification of a DTT signal can cause set top boxes not to work properly. The set top box appears not to be able to decode the DTT service even though there a stong signal. 

 

Similar steps will be taken prior to the second digital dividend around 2021.

 The ITU World Radiocommunications Conference 2012 (WRC12) decided to make more UHF spectrum (694-790 MHz) available to mobile telephony. This is a second digital dividend.  ITU groups and CEPT groups decided that the mobile telephony band plan used in Asia would be adopted for Europe. This band plan allows cellular telephony to use 60MHz. Experts think that security and emergency service radio systems and radio microphones could also use part of the second digital dividend spectrum.

 Ofcom UK are already in discussions with ComReg about a new TV channel plan. this replanning process includes 2rn (formerly RTE Networks Ltd) and Arquiva, the transmission network operator in the UK. ComReg is expect to complete this replanning before the end of 2017.

TV manufacturers might install adequate filters in TV receivers; otherwise households may need to fit new filters after the second digital dividend.